treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / infiniband / hw / hfi1 / file_ops.c

/*
 * Copyright(c) 2015-2017 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <linux/poll.h>
#include <linux/cdev.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <linux/sched/mm.h>
#include <linux/bitmap.h>

#include <rdma/ib.h>

#include "hfi.h"
#include "pio.h"
#include "device.h"
#include "common.h"
#include "trace.h"
#include "mmu_rb.h"
#include "user_sdma.h"
#include "user_exp_rcv.h"
#include "aspm.h"

#undef pr_fmt
#define pr_fmt(fmt) DRIVER_NAME ": " fmt

#define SEND_CTXT_HALT_TIMEOUT 1000 /* msecs */

/*
 * File operation functions
 */
static int hfi1_file_open(struct inode *inode, struct file *fp);
static int hfi1_file_close(struct inode *inode, struct file *fp);
static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from);
static __poll_t hfi1_poll(struct file *fp, struct poll_table_struct *pt);
static int hfi1_file_mmap(struct file *fp, struct vm_area_struct *vma);

static u64 kvirt_to_phys(void *addr);
static int assign_ctxt(struct hfi1_filedata *fd, unsigned long arg, u32 len);
static void init_subctxts(struct hfi1_ctxtdata *uctxt,
                          const struct hfi1_user_info *uinfo);
static int init_user_ctxt(struct hfi1_filedata *fd,
                          struct hfi1_ctxtdata *uctxt);
static void user_init(struct hfi1_ctxtdata *uctxt);
static int get_ctxt_info(struct hfi1_filedata *fd, unsigned long arg, u32 len);
static int get_base_info(struct hfi1_filedata *fd, unsigned long arg, u32 len);
static int user_exp_rcv_setup(struct hfi1_filedata *fd, unsigned long arg,
                              u32 len);
static int user_exp_rcv_clear(struct hfi1_filedata *fd, unsigned long arg,
                              u32 len);
static int user_exp_rcv_invalid(struct hfi1_filedata *fd, unsigned long arg,
                                u32 len);
static int setup_base_ctxt(struct hfi1_filedata *fd,
                           struct hfi1_ctxtdata *uctxt);
static int setup_subctxt(struct hfi1_ctxtdata *uctxt);

static int find_sub_ctxt(struct hfi1_filedata *fd,
                         const struct hfi1_user_info *uinfo);
static int allocate_ctxt(struct hfi1_filedata *fd, struct hfi1_devdata *dd,
                         struct hfi1_user_info *uinfo,
                         struct hfi1_ctxtdata **cd);
static void deallocate_ctxt(struct hfi1_ctxtdata *uctxt);
static __poll_t poll_urgent(struct file *fp, struct poll_table_struct *pt);
static __poll_t poll_next(struct file *fp, struct poll_table_struct *pt);
static int user_event_ack(struct hfi1_ctxtdata *uctxt, u16 subctxt,
                          unsigned long arg);
static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, unsigned long arg);
static int ctxt_reset(struct hfi1_ctxtdata *uctxt);
static int manage_rcvq(struct hfi1_ctxtdata *uctxt, u16 subctxt,
                       unsigned long arg);
static vm_fault_t vma_fault(struct vm_fault *vmf);
static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
                            unsigned long arg);

static const struct file_operations hfi1_file_ops = {
        .owner = THIS_MODULE,
        .write_iter = hfi1_write_iter,
        .open = hfi1_file_open,
        .release = hfi1_file_close,
        .unlocked_ioctl = hfi1_file_ioctl,
        .poll = hfi1_poll,
        .mmap = hfi1_file_mmap,
        .llseek = noop_llseek,
};

static const struct vm_operations_struct vm_ops = {
        .fault = vma_fault,
};

/*
 * Types of memories mapped into user processes' space
 */
enum mmap_types {
        PIO_BUFS = 1,
        PIO_BUFS_SOP,
        PIO_CRED,
        RCV_HDRQ,
        RCV_EGRBUF,
        UREGS,
        EVENTS,
        STATUS,
        RTAIL,
        SUBCTXT_UREGS,
        SUBCTXT_RCV_HDRQ,
        SUBCTXT_EGRBUF,
        SDMA_COMP
};

/*
 * Masks and offsets defining the mmap tokens
 */
#define HFI1_MMAP_OFFSET_MASK   0xfffULL
#define HFI1_MMAP_OFFSET_SHIFT  0
#define HFI1_MMAP_SUBCTXT_MASK  0xfULL
#define HFI1_MMAP_SUBCTXT_SHIFT 12
#define HFI1_MMAP_CTXT_MASK     0xffULL
#define HFI1_MMAP_CTXT_SHIFT    16
#define HFI1_MMAP_TYPE_MASK     0xfULL
#define HFI1_MMAP_TYPE_SHIFT    24
#define HFI1_MMAP_MAGIC_MASK    0xffffffffULL
#define HFI1_MMAP_MAGIC_SHIFT   32

#define HFI1_MMAP_MAGIC         0xdabbad00

#define HFI1_MMAP_TOKEN_SET(field, val) \
        (((val) & HFI1_MMAP_##field##_MASK) << HFI1_MMAP_##field##_SHIFT)
#define HFI1_MMAP_TOKEN_GET(field, token) \
        (((token) >> HFI1_MMAP_##field##_SHIFT) & HFI1_MMAP_##field##_MASK)
#define HFI1_MMAP_TOKEN(type, ctxt, subctxt, addr)   \
        (HFI1_MMAP_TOKEN_SET(MAGIC, HFI1_MMAP_MAGIC) | \
        HFI1_MMAP_TOKEN_SET(TYPE, type) | \
        HFI1_MMAP_TOKEN_SET(CTXT, ctxt) | \
        HFI1_MMAP_TOKEN_SET(SUBCTXT, subctxt) | \
        HFI1_MMAP_TOKEN_SET(OFFSET, (offset_in_page(addr))))

#define dbg(fmt, ...)                           \
        pr_info(fmt, ##__VA_ARGS__)

static inline int is_valid_mmap(u64 token)
{
        return (HFI1_MMAP_TOKEN_GET(MAGIC, token) == HFI1_MMAP_MAGIC);
}

static int hfi1_file_open(struct inode *inode, struct file *fp)
{
        struct hfi1_filedata *fd;
        struct hfi1_devdata *dd = container_of(inode->i_cdev,
                                               struct hfi1_devdata,
                                               user_cdev);

        if (!((dd->flags & HFI1_PRESENT) && dd->kregbase1))
                return -EINVAL;

        if (!atomic_inc_not_zero(&dd->user_refcount))
                return -ENXIO;

        /* The real work is performed later in assign_ctxt() */

        fd = kzalloc(sizeof(*fd), GFP_KERNEL);

        if (fd) {
                fd->rec_cpu_num = -1; /* no cpu affinity by default */
                fd->mm = current->mm;
                mmgrab(fd->mm);
                fd->dd = dd;
                kobject_get(&fd->dd->kobj);
                fp->private_data = fd;
        } else {
                fp->private_data = NULL;

                if (atomic_dec_and_test(&dd->user_refcount))
                        complete(&dd->user_comp);

                return -ENOMEM;
        }

        return 0;
}

static long hfi1_file_ioctl(struct file *fp, unsigned int cmd,
                            unsigned long arg)
{
        struct hfi1_filedata *fd = fp->private_data;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;
        int ret = 0;
        int uval = 0;

        hfi1_cdbg(IOCTL, "IOCTL recv: 0x%x", cmd);
        if (cmd != HFI1_IOCTL_ASSIGN_CTXT &&
            cmd != HFI1_IOCTL_GET_VERS &&
            !uctxt)
                return -EINVAL;

        switch (cmd) {
        case HFI1_IOCTL_ASSIGN_CTXT:
                ret = assign_ctxt(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_CTXT_INFO:
                ret = get_ctxt_info(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_USER_INFO:
                ret = get_base_info(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_CREDIT_UPD:
                if (uctxt)
                        sc_return_credits(uctxt->sc);
                break;

        case HFI1_IOCTL_TID_UPDATE:
                ret = user_exp_rcv_setup(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_TID_FREE:
                ret = user_exp_rcv_clear(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_TID_INVAL_READ:
                ret = user_exp_rcv_invalid(fd, arg, _IOC_SIZE(cmd));
                break;

        case HFI1_IOCTL_RECV_CTRL:
                ret = manage_rcvq(uctxt, fd->subctxt, arg);
                break;

        case HFI1_IOCTL_POLL_TYPE:
                if (get_user(uval, (int __user *)arg))
                        return -EFAULT;
                uctxt->poll_type = (typeof(uctxt->poll_type))uval;
                break;

        case HFI1_IOCTL_ACK_EVENT:
                ret = user_event_ack(uctxt, fd->subctxt, arg);
                break;

        case HFI1_IOCTL_SET_PKEY:
                ret = set_ctxt_pkey(uctxt, arg);
                break;

        case HFI1_IOCTL_CTXT_RESET:
                ret = ctxt_reset(uctxt);
                break;

        case HFI1_IOCTL_GET_VERS:
                uval = HFI1_USER_SWVERSION;
                if (put_user(uval, (int __user *)arg))
                        return -EFAULT;
                break;

        default:
                return -EINVAL;
        }

        return ret;
}

static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
{
        struct hfi1_filedata *fd = kiocb->ki_filp->private_data;
        struct hfi1_user_sdma_pkt_q *pq = fd->pq;
        struct hfi1_user_sdma_comp_q *cq = fd->cq;
        int done = 0, reqs = 0;
        unsigned long dim = from->nr_segs;

        if (!cq || !pq)
                return -EIO;

        if (!iter_is_iovec(from) || !dim)
                return -EINVAL;

        trace_hfi1_sdma_request(fd->dd, fd->uctxt->ctxt, fd->subctxt, dim);

        if (atomic_read(&pq->n_reqs) == pq->n_max_reqs)
                return -ENOSPC;

        while (dim) {
                int ret;
                unsigned long count = 0;

                ret = hfi1_user_sdma_process_request(
                        fd, (struct iovec *)(from->iov + done),
                        dim, &count);
                if (ret) {
                        reqs = ret;
                        break;
                }
                dim -= count;
                done += count;
                reqs++;
        }

        return reqs;
}

static int hfi1_file_mmap(struct file *fp, struct vm_area_struct *vma)
{
        struct hfi1_filedata *fd = fp->private_data;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;
        struct hfi1_devdata *dd;
        unsigned long flags;
        u64 token = vma->vm_pgoff << PAGE_SHIFT,
                memaddr = 0;
        void *memvirt = NULL;
        u8 subctxt, mapio = 0, vmf = 0, type;
        ssize_t memlen = 0;
        int ret = 0;
        u16 ctxt;

        if (!is_valid_mmap(token) || !uctxt ||
            !(vma->vm_flags & VM_SHARED)) {
                ret = -EINVAL;
                goto done;
        }
        dd = uctxt->dd;
        ctxt = HFI1_MMAP_TOKEN_GET(CTXT, token);
        subctxt = HFI1_MMAP_TOKEN_GET(SUBCTXT, token);
        type = HFI1_MMAP_TOKEN_GET(TYPE, token);
        if (ctxt != uctxt->ctxt || subctxt != fd->subctxt) {
                ret = -EINVAL;
                goto done;
        }

        flags = vma->vm_flags;

        switch (type) {
        case PIO_BUFS:
        case PIO_BUFS_SOP:
                memaddr = ((dd->physaddr + TXE_PIO_SEND) +
                                /* chip pio base */
                           (uctxt->sc->hw_context * BIT(16))) +
                                /* 64K PIO space / ctxt */
                        (type == PIO_BUFS_SOP ?
                                (TXE_PIO_SIZE / 2) : 0); /* sop? */
                /*
                 * Map only the amount allocated to the context, not the
                 * entire available context's PIO space.
                 */
                memlen = PAGE_ALIGN(uctxt->sc->credits * PIO_BLOCK_SIZE);
                flags &= ~VM_MAYREAD;
                flags |= VM_DONTCOPY | VM_DONTEXPAND;
                vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
                mapio = 1;
                break;
        case PIO_CRED:
                if (flags & VM_WRITE) {
                        ret = -EPERM;
                        goto done;
                }
                /*
                 * The credit return location for this context could be on the
                 * second or third page allocated for credit returns (if number
                 * of enabled contexts > 64 and 128 respectively).
                 */
                memvirt = dd->cr_base[uctxt->numa_id].va;
                memaddr = virt_to_phys(memvirt) +
                        (((u64)uctxt->sc->hw_free -
                          (u64)dd->cr_base[uctxt->numa_id].va) & PAGE_MASK);
                memlen = PAGE_SIZE;
                flags &= ~VM_MAYWRITE;
                flags |= VM_DONTCOPY | VM_DONTEXPAND;
                /*
                 * The driver has already allocated memory for credit
                 * returns and programmed it into the chip. Has that
                 * memory been flagged as non-cached?
                 */
                /* vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); */
                mapio = 1;
                break;
        case RCV_HDRQ:
                memlen = rcvhdrq_size(uctxt);
                memvirt = uctxt->rcvhdrq;
                break;
        case RCV_EGRBUF: {
                unsigned long addr;
                int i;
                /*
                 * The RcvEgr buffer need to be handled differently
                 * as multiple non-contiguous pages need to be mapped
                 * into the user process.
                 */
                memlen = uctxt->egrbufs.size;
                if ((vma->vm_end - vma->vm_start) != memlen) {
                        dd_dev_err(dd, "Eager buffer map size invalid (%lu != %lu)\n",
                                   (vma->vm_end - vma->vm_start), memlen);
                        ret = -EINVAL;
                        goto done;
                }
                if (vma->vm_flags & VM_WRITE) {
                        ret = -EPERM;
                        goto done;
                }
                vma->vm_flags &= ~VM_MAYWRITE;
                addr = vma->vm_start;
                for (i = 0 ; i < uctxt->egrbufs.numbufs; i++) {
                        memlen = uctxt->egrbufs.buffers[i].len;
                        memvirt = uctxt->egrbufs.buffers[i].addr;
                        ret = remap_pfn_range(
                                vma, addr,
                                /*
                                 * virt_to_pfn() does the same, but
                                 * it's not available on x86_64
                                 * when CONFIG_MMU is enabled.
                                 */
                                PFN_DOWN(__pa(memvirt)),
                                memlen,
                                vma->vm_page_prot);
                        if (ret < 0)
                                goto done;
                        addr += memlen;
                }
                ret = 0;
                goto done;
        }
        case UREGS:
                /*
                 * Map only the page that contains this context's user
                 * registers.
                 */
                memaddr = (unsigned long)
                        (dd->physaddr + RXE_PER_CONTEXT_USER)
                        + (uctxt->ctxt * RXE_PER_CONTEXT_SIZE);
                /*
                 * TidFlow table is on the same page as the rest of the
                 * user registers.
                 */
                memlen = PAGE_SIZE;
                flags |= VM_DONTCOPY | VM_DONTEXPAND;
                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
                mapio = 1;
                break;
        case EVENTS:
                /*
                 * Use the page where this context's flags are. User level
                 * knows where it's own bitmap is within the page.
                 */
                memaddr = (unsigned long)
                        (dd->events + uctxt_offset(uctxt)) & PAGE_MASK;
                memlen = PAGE_SIZE;
                /*
                 * v3.7 removes VM_RESERVED but the effect is kept by
                 * using VM_IO.
                 */
                flags |= VM_IO | VM_DONTEXPAND;
                vmf = 1;
                break;
        case STATUS:
                if (flags & VM_WRITE) {
                        ret = -EPERM;
                        goto done;
                }
                memaddr = kvirt_to_phys((void *)dd->status);
                memlen = PAGE_SIZE;
                flags |= VM_IO | VM_DONTEXPAND;
                break;
        case RTAIL:
                if (!HFI1_CAP_IS_USET(DMA_RTAIL)) {
                        /*
                         * If the memory allocation failed, the context alloc
                         * also would have failed, so we would never get here
                         */
                        ret = -EINVAL;
                        goto done;
                }
                if ((flags & VM_WRITE) || !hfi1_rcvhdrtail_kvaddr(uctxt)) {
                        ret = -EPERM;
                        goto done;
                }
                memlen = PAGE_SIZE;
                memvirt = (void *)hfi1_rcvhdrtail_kvaddr(uctxt);
                flags &= ~VM_MAYWRITE;
                break;
        case SUBCTXT_UREGS:
                memaddr = (u64)uctxt->subctxt_uregbase;
                memlen = PAGE_SIZE;
                flags |= VM_IO | VM_DONTEXPAND;
                vmf = 1;
                break;
        case SUBCTXT_RCV_HDRQ:
                memaddr = (u64)uctxt->subctxt_rcvhdr_base;
                memlen = rcvhdrq_size(uctxt) * uctxt->subctxt_cnt;
                flags |= VM_IO | VM_DONTEXPAND;
                vmf = 1;
                break;
        case SUBCTXT_EGRBUF:
                memaddr = (u64)uctxt->subctxt_rcvegrbuf;
                memlen = uctxt->egrbufs.size * uctxt->subctxt_cnt;
                flags |= VM_IO | VM_DONTEXPAND;
                flags &= ~VM_MAYWRITE;
                vmf = 1;
                break;
        case SDMA_COMP: {
                struct hfi1_user_sdma_comp_q *cq = fd->cq;

                if (!cq) {
                        ret = -EFAULT;
                        goto done;
                }
                memaddr = (u64)cq->comps;
                memlen = PAGE_ALIGN(sizeof(*cq->comps) * cq->nentries);
                flags |= VM_IO | VM_DONTEXPAND;
                vmf = 1;
                break;
        }
        default:
                ret = -EINVAL;
                break;
        }

        if ((vma->vm_end - vma->vm_start) != memlen) {
                hfi1_cdbg(PROC, "%u:%u Memory size mismatch %lu:%lu",
                          uctxt->ctxt, fd->subctxt,
                          (vma->vm_end - vma->vm_start), memlen);
                ret = -EINVAL;
                goto done;
        }

        vma->vm_flags = flags;
        hfi1_cdbg(PROC,
                  "%u:%u type:%u io/vf:%d/%d, addr:0x%llx, len:%lu(%lu), flags:0x%lx\n",
                    ctxt, subctxt, type, mapio, vmf, memaddr, memlen,
                    vma->vm_end - vma->vm_start, vma->vm_flags);
        if (vmf) {
                vma->vm_pgoff = PFN_DOWN(memaddr);
                vma->vm_ops = &vm_ops;
                ret = 0;
        } else if (mapio) {
                ret = io_remap_pfn_range(vma, vma->vm_start,
                                         PFN_DOWN(memaddr),
                                         memlen,
                                         vma->vm_page_prot);
        } else if (memvirt) {
                ret = remap_pfn_range(vma, vma->vm_start,
                                      PFN_DOWN(__pa(memvirt)),
                                      memlen,
                                      vma->vm_page_prot);
        } else {
                ret = remap_pfn_range(vma, vma->vm_start,
                                      PFN_DOWN(memaddr),
                                      memlen,
                                      vma->vm_page_prot);
        }
done:
        return ret;
}

/*
 * Local (non-chip) user memory is not mapped right away but as it is
 * accessed by the user-level code.
 */
static vm_fault_t vma_fault(struct vm_fault *vmf)
{
        struct page *page;

        page = vmalloc_to_page((void *)(vmf->pgoff << PAGE_SHIFT));
        if (!page)
                return VM_FAULT_SIGBUS;

        get_page(page);
        vmf->page = page;

        return 0;
}

static __poll_t hfi1_poll(struct file *fp, struct poll_table_struct *pt)
{
        struct hfi1_ctxtdata *uctxt;
        __poll_t pollflag;

        uctxt = ((struct hfi1_filedata *)fp->private_data)->uctxt;
        if (!uctxt)
                pollflag = EPOLLERR;
        else if (uctxt->poll_type == HFI1_POLL_TYPE_URGENT)
                pollflag = poll_urgent(fp, pt);
        else  if (uctxt->poll_type == HFI1_POLL_TYPE_ANYRCV)
                pollflag = poll_next(fp, pt);
        else /* invalid */
                pollflag = EPOLLERR;

        return pollflag;
}

static int hfi1_file_close(struct inode *inode, struct file *fp)
{
        struct hfi1_filedata *fdata = fp->private_data;
        struct hfi1_ctxtdata *uctxt = fdata->uctxt;
        struct hfi1_devdata *dd = container_of(inode->i_cdev,
                                               struct hfi1_devdata,
                                               user_cdev);
        unsigned long flags, *ev;

        fp->private_data = NULL;

        if (!uctxt)
                goto done;

        hfi1_cdbg(PROC, "closing ctxt %u:%u", uctxt->ctxt, fdata->subctxt);

        flush_wc();
        /* drain user sdma queue */
        hfi1_user_sdma_free_queues(fdata, uctxt);

        /* release the cpu */
        hfi1_put_proc_affinity(fdata->rec_cpu_num);

        /* clean up rcv side */
        hfi1_user_exp_rcv_free(fdata);

        /*
         * fdata->uctxt is used in the above cleanup.  It is not ready to be
         * removed until here.
         */
        fdata->uctxt = NULL;
        hfi1_rcd_put(uctxt);

        /*
         * Clear any left over, unhandled events so the next process that
         * gets this context doesn't get confused.
         */
        ev = dd->events + uctxt_offset(uctxt) + fdata->subctxt;
        *ev = 0;

        spin_lock_irqsave(&dd->uctxt_lock, flags);
        __clear_bit(fdata->subctxt, uctxt->in_use_ctxts);
        if (!bitmap_empty(uctxt->in_use_ctxts, HFI1_MAX_SHARED_CTXTS)) {
                spin_unlock_irqrestore(&dd->uctxt_lock, flags);
                goto done;
        }
        spin_unlock_irqrestore(&dd->uctxt_lock, flags);

        /*
         * Disable receive context and interrupt available, reset all
         * RcvCtxtCtrl bits to default values.
         */
        hfi1_rcvctrl(dd, HFI1_RCVCTRL_CTXT_DIS |
                     HFI1_RCVCTRL_TIDFLOW_DIS |
                     HFI1_RCVCTRL_INTRAVAIL_DIS |
                     HFI1_RCVCTRL_TAILUPD_DIS |
                     HFI1_RCVCTRL_ONE_PKT_EGR_DIS |
                     HFI1_RCVCTRL_NO_RHQ_DROP_DIS |
                     HFI1_RCVCTRL_NO_EGR_DROP_DIS |
                     HFI1_RCVCTRL_URGENT_DIS, uctxt);
        /* Clear the context's J_KEY */
        hfi1_clear_ctxt_jkey(dd, uctxt);
        /*
         * If a send context is allocated, reset context integrity
         * checks to default and disable the send context.
         */
        if (uctxt->sc) {
                sc_disable(uctxt->sc);
                set_pio_integrity(uctxt->sc);
        }

        hfi1_free_ctxt_rcv_groups(uctxt);
        hfi1_clear_ctxt_pkey(dd, uctxt);

        uctxt->event_flags = 0;

        deallocate_ctxt(uctxt);
done:
        mmdrop(fdata->mm);
        kobject_put(&dd->kobj);

        if (atomic_dec_and_test(&dd->user_refcount))
                complete(&dd->user_comp);

        kfree(fdata);
        return 0;
}

/*
 * Convert kernel *virtual* addresses to physical addresses.
 * This is used to vmalloc'ed addresses.
 */
static u64 kvirt_to_phys(void *addr)
{
        struct page *page;
        u64 paddr = 0;

        page = vmalloc_to_page(addr);
        if (page)
                paddr = page_to_pfn(page) << PAGE_SHIFT;

        return paddr;
}

/**
 * complete_subctxt
 * @fd: valid filedata pointer
 *
 * Sub-context info can only be set up after the base context
 * has been completed.  This is indicated by the clearing of the
 * HFI1_CTXT_BASE_UINIT bit.
 *
 * Wait for the bit to be cleared, and then complete the subcontext
 * initialization.
 *
 */
static int complete_subctxt(struct hfi1_filedata *fd)
{
        int ret;
        unsigned long flags;

        /*
         * sub-context info can only be set up after the base context
         * has been completed.
         */
        ret = wait_event_interruptible(
                fd->uctxt->wait,
                !test_bit(HFI1_CTXT_BASE_UNINIT, &fd->uctxt->event_flags));

        if (test_bit(HFI1_CTXT_BASE_FAILED, &fd->uctxt->event_flags))
                ret = -ENOMEM;

        /* Finish the sub-context init */
        if (!ret) {
                fd->rec_cpu_num = hfi1_get_proc_affinity(fd->uctxt->numa_id);
                ret = init_user_ctxt(fd, fd->uctxt);
        }

        if (ret) {
                spin_lock_irqsave(&fd->dd->uctxt_lock, flags);
                __clear_bit(fd->subctxt, fd->uctxt->in_use_ctxts);
                spin_unlock_irqrestore(&fd->dd->uctxt_lock, flags);
                hfi1_rcd_put(fd->uctxt);
                fd->uctxt = NULL;
        }

        return ret;
}

static int assign_ctxt(struct hfi1_filedata *fd, unsigned long arg, u32 len)
{
        int ret;
        unsigned int swmajor;
        struct hfi1_ctxtdata *uctxt = NULL;
        struct hfi1_user_info uinfo;

        if (fd->uctxt)
                return -EINVAL;

        if (sizeof(uinfo) != len)
                return -EINVAL;

        if (copy_from_user(&uinfo, (void __user *)arg, sizeof(uinfo)))
                return -EFAULT;

        swmajor = uinfo.userversion >> 16;
        if (swmajor != HFI1_USER_SWMAJOR)
                return -ENODEV;

        if (uinfo.subctxt_cnt > HFI1_MAX_SHARED_CTXTS)
                return -EINVAL;

        /*
         * Acquire the mutex to protect against multiple creations of what
         * could be a shared base context.
         */
        mutex_lock(&hfi1_mutex);
        /*
         * Get a sub context if available  (fd->uctxt will be set).
         * ret < 0 error, 0 no context, 1 sub-context found
         */
        ret = find_sub_ctxt(fd, &uinfo);

        /*
         * Allocate a base context if context sharing is not required or a
         * sub context wasn't found.
         */
        if (!ret)
                ret = allocate_ctxt(fd, fd->dd, &uinfo, &uctxt);

        mutex_unlock(&hfi1_mutex);

        /* Depending on the context type, finish the appropriate init */
        switch (ret) {
        case 0:
                ret = setup_base_ctxt(fd, uctxt);
                if (ret)
                        deallocate_ctxt(uctxt);
                break;
        case 1:
                ret = complete_subctxt(fd);
                break;
        default:
                break;
        }

        return ret;
}

/**
 * match_ctxt
 * @fd: valid filedata pointer
 * @uinfo: user info to compare base context with
 * @uctxt: context to compare uinfo to.
 *
 * Compare the given context with the given information to see if it
 * can be used for a sub context.
 */
static int match_ctxt(struct hfi1_filedata *fd,
                      const struct hfi1_user_info *uinfo,
                      struct hfi1_ctxtdata *uctxt)
{
        struct hfi1_devdata *dd = fd->dd;
        unsigned long flags;
        u16 subctxt;

        /* Skip dynamically allocated kernel contexts */
        if (uctxt->sc && (uctxt->sc->type == SC_KERNEL))
                return 0;

        /* Skip ctxt if it doesn't match the requested one */
        if (memcmp(uctxt->uuid, uinfo->uuid, sizeof(uctxt->uuid)) ||
            uctxt->jkey != generate_jkey(current_uid()) ||
            uctxt->subctxt_id != uinfo->subctxt_id ||
            uctxt->subctxt_cnt != uinfo->subctxt_cnt)
                return 0;

        /* Verify the sharing process matches the base */
        if (uctxt->userversion != uinfo->userversion)
                return -EINVAL;

        /* Find an unused sub context */
        spin_lock_irqsave(&dd->uctxt_lock, flags);
        if (bitmap_empty(uctxt->in_use_ctxts, HFI1_MAX_SHARED_CTXTS)) {
                /* context is being closed, do not use */
                spin_unlock_irqrestore(&dd->uctxt_lock, flags);
                return 0;
        }

        subctxt = find_first_zero_bit(uctxt->in_use_ctxts,
                                      HFI1_MAX_SHARED_CTXTS);
        if (subctxt >= uctxt->subctxt_cnt) {
                spin_unlock_irqrestore(&dd->uctxt_lock, flags);
                return -EBUSY;
        }

        fd->subctxt = subctxt;
        __set_bit(fd->subctxt, uctxt->in_use_ctxts);
        spin_unlock_irqrestore(&dd->uctxt_lock, flags);

        fd->uctxt = uctxt;
        hfi1_rcd_get(uctxt);

        return 1;
}

/**
 * find_sub_ctxt
 * @fd: valid filedata pointer
 * @uinfo: matching info to use to find a possible context to share.
 *
 * The hfi1_mutex must be held when this function is called.  It is
 * necessary to ensure serialized creation of shared contexts.
 *
 * Return:
 *    0      No sub-context found
 *    1      Subcontext found and allocated
 *    errno  EINVAL (incorrect parameters)
 *           EBUSY (all sub contexts in use)
 */
static int find_sub_ctxt(struct hfi1_filedata *fd,
                         const struct hfi1_user_info *uinfo)
{
        struct hfi1_ctxtdata *uctxt;
        struct hfi1_devdata *dd = fd->dd;
        u16 i;
        int ret;

        if (!uinfo->subctxt_cnt)
                return 0;

        for (i = dd->first_dyn_alloc_ctxt; i < dd->num_rcv_contexts; i++) {
                uctxt = hfi1_rcd_get_by_index(dd, i);
                if (uctxt) {
                        ret = match_ctxt(fd, uinfo, uctxt);
                        hfi1_rcd_put(uctxt);
                        /* value of != 0 will return */
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

static int allocate_ctxt(struct hfi1_filedata *fd, struct hfi1_devdata *dd,
                         struct hfi1_user_info *uinfo,
                         struct hfi1_ctxtdata **rcd)
{
        struct hfi1_ctxtdata *uctxt;
        int ret, numa;

        if (dd->flags & HFI1_FROZEN) {
                /*
                 * Pick an error that is unique from all other errors
                 * that are returned so the user process knows that
                 * it tried to allocate while the SPC was frozen.  It
                 * it should be able to retry with success in a short
                 * while.
                 */
                return -EIO;
        }

        if (!dd->freectxts)
                return -EBUSY;

        /*
         * If we don't have a NUMA node requested, preference is towards
         * device NUMA node.
         */
        fd->rec_cpu_num = hfi1_get_proc_affinity(dd->node);
        if (fd->rec_cpu_num != -1)
                numa = cpu_to_node(fd->rec_cpu_num);
        else
                numa = numa_node_id();
        ret = hfi1_create_ctxtdata(dd->pport, numa, &uctxt);
        if (ret < 0) {
                dd_dev_err(dd, "user ctxtdata allocation failed\n");
                return ret;
        }
        hfi1_cdbg(PROC, "[%u:%u] pid %u assigned to CPU %d (NUMA %u)",
                  uctxt->ctxt, fd->subctxt, current->pid, fd->rec_cpu_num,
                  uctxt->numa_id);

        /*
         * Allocate and enable a PIO send context.
         */
        uctxt->sc = sc_alloc(dd, SC_USER, uctxt->rcvhdrqentsize, dd->node);
        if (!uctxt->sc) {
                ret = -ENOMEM;
                goto ctxdata_free;
        }
        hfi1_cdbg(PROC, "allocated send context %u(%u)\n", uctxt->sc->sw_index,
                  uctxt->sc->hw_context);
        ret = sc_enable(uctxt->sc);
        if (ret)
                goto ctxdata_free;

        /*
         * Setup sub context information if the user-level has requested
         * sub contexts.
         * This has to be done here so the rest of the sub-contexts find the
         * proper base context.
         * NOTE: _set_bit() can be used here because the context creation is
         * protected by the mutex (rather than the spin_lock), and will be the
         * very first instance of this context.
         */
        __set_bit(0, uctxt->in_use_ctxts);
        if (uinfo->subctxt_cnt)
                init_subctxts(uctxt, uinfo);
        uctxt->userversion = uinfo->userversion;
        uctxt->flags = hfi1_cap_mask; /* save current flag state */
        init_waitqueue_head(&uctxt->wait);
        strlcpy(uctxt->comm, current->comm, sizeof(uctxt->comm));
        memcpy(uctxt->uuid, uinfo->uuid, sizeof(uctxt->uuid));
        uctxt->jkey = generate_jkey(current_uid());
        hfi1_stats.sps_ctxts++;
        /*
         * Disable ASPM when there are open user/PSM contexts to avoid
         * issues with ASPM L1 exit latency
         */
        if (dd->freectxts-- == dd->num_user_contexts)
                aspm_disable_all(dd);

        *rcd = uctxt;

        return 0;

ctxdata_free:
        hfi1_free_ctxt(uctxt);
        return ret;
}

static void deallocate_ctxt(struct hfi1_ctxtdata *uctxt)
{
        mutex_lock(&hfi1_mutex);
        hfi1_stats.sps_ctxts--;
        if (++uctxt->dd->freectxts == uctxt->dd->num_user_contexts)
                aspm_enable_all(uctxt->dd);
        mutex_unlock(&hfi1_mutex);

        hfi1_free_ctxt(uctxt);
}

static void init_subctxts(struct hfi1_ctxtdata *uctxt,
                          const struct hfi1_user_info *uinfo)
{
        uctxt->subctxt_cnt = uinfo->subctxt_cnt;
        uctxt->subctxt_id = uinfo->subctxt_id;
        set_bit(HFI1_CTXT_BASE_UNINIT, &uctxt->event_flags);
}

static int setup_subctxt(struct hfi1_ctxtdata *uctxt)
{
        int ret = 0;
        u16 num_subctxts = uctxt->subctxt_cnt;

        uctxt->subctxt_uregbase = vmalloc_user(PAGE_SIZE);
        if (!uctxt->subctxt_uregbase)
                return -ENOMEM;

        /* We can take the size of the RcvHdr Queue from the master */
        uctxt->subctxt_rcvhdr_base = vmalloc_user(rcvhdrq_size(uctxt) *
                                                  num_subctxts);
        if (!uctxt->subctxt_rcvhdr_base) {
                ret = -ENOMEM;
                goto bail_ureg;
        }

        uctxt->subctxt_rcvegrbuf = vmalloc_user(uctxt->egrbufs.size *
                                                num_subctxts);
        if (!uctxt->subctxt_rcvegrbuf) {
                ret = -ENOMEM;
                goto bail_rhdr;
        }

        return 0;

bail_rhdr:
        vfree(uctxt->subctxt_rcvhdr_base);
        uctxt->subctxt_rcvhdr_base = NULL;
bail_ureg:
        vfree(uctxt->subctxt_uregbase);
        uctxt->subctxt_uregbase = NULL;

        return ret;
}

static void user_init(struct hfi1_ctxtdata *uctxt)
{
        unsigned int rcvctrl_ops = 0;

        /* initialize poll variables... */
        uctxt->urgent = 0;
        uctxt->urgent_poll = 0;

        /*
         * Now enable the ctxt for receive.
         * For chips that are set to DMA the tail register to memory
         * when they change (and when the update bit transitions from
         * 0 to 1.  So for those chips, we turn it off and then back on.
         * This will (very briefly) affect any other open ctxts, but the
         * duration is very short, and therefore isn't an issue.  We
         * explicitly set the in-memory tail copy to 0 beforehand, so we
         * don't have to wait to be sure the DMA update has happened
         * (chip resets head/tail to 0 on transition to enable).
         */
        if (hfi1_rcvhdrtail_kvaddr(uctxt))
                clear_rcvhdrtail(uctxt);

        /* Setup J_KEY before enabling the context */
        hfi1_set_ctxt_jkey(uctxt->dd, uctxt, uctxt->jkey);

        rcvctrl_ops = HFI1_RCVCTRL_CTXT_ENB;
        rcvctrl_ops |= HFI1_RCVCTRL_URGENT_ENB;
        if (HFI1_CAP_UGET_MASK(uctxt->flags, HDRSUPP))
                rcvctrl_ops |= HFI1_RCVCTRL_TIDFLOW_ENB;
        /*
         * Ignore the bit in the flags for now until proper
         * support for multiple packet per rcv array entry is
         * added.
         */
        if (!HFI1_CAP_UGET_MASK(uctxt->flags, MULTI_PKT_EGR))
                rcvctrl_ops |= HFI1_RCVCTRL_ONE_PKT_EGR_ENB;
        if (HFI1_CAP_UGET_MASK(uctxt->flags, NODROP_EGR_FULL))
                rcvctrl_ops |= HFI1_RCVCTRL_NO_EGR_DROP_ENB;
        if (HFI1_CAP_UGET_MASK(uctxt->flags, NODROP_RHQ_FULL))
                rcvctrl_ops |= HFI1_RCVCTRL_NO_RHQ_DROP_ENB;
        /*
         * The RcvCtxtCtrl.TailUpd bit has to be explicitly written.
         * We can't rely on the correct value to be set from prior
         * uses of the chip or ctxt. Therefore, add the rcvctrl op
         * for both cases.
         */
        if (HFI1_CAP_UGET_MASK(uctxt->flags, DMA_RTAIL))
                rcvctrl_ops |= HFI1_RCVCTRL_TAILUPD_ENB;
        else
                rcvctrl_ops |= HFI1_RCVCTRL_TAILUPD_DIS;
        hfi1_rcvctrl(uctxt->dd, rcvctrl_ops, uctxt);
}

static int get_ctxt_info(struct hfi1_filedata *fd, unsigned long arg, u32 len)
{
        struct hfi1_ctxt_info cinfo;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;

        if (sizeof(cinfo) != len)
                return -EINVAL;

        memset(&cinfo, 0, sizeof(cinfo));
        cinfo.runtime_flags = (((uctxt->flags >> HFI1_CAP_MISC_SHIFT) &
                                HFI1_CAP_MISC_MASK) << HFI1_CAP_USER_SHIFT) |
                        HFI1_CAP_UGET_MASK(uctxt->flags, MASK) |
                        HFI1_CAP_KGET_MASK(uctxt->flags, K2U);
        /* adjust flag if this fd is not able to cache */
        if (!fd->use_mn)
                cinfo.runtime_flags |= HFI1_CAP_TID_UNMAP; /* no caching */

        cinfo.num_active = hfi1_count_active_units();
        cinfo.unit = uctxt->dd->unit;
        cinfo.ctxt = uctxt->ctxt;
        cinfo.subctxt = fd->subctxt;
        cinfo.rcvtids = roundup(uctxt->egrbufs.alloced,
                                uctxt->dd->rcv_entries.group_size) +
                uctxt->expected_count;
        cinfo.credits = uctxt->sc->credits;
        cinfo.numa_node = uctxt->numa_id;
        cinfo.rec_cpu = fd->rec_cpu_num;
        cinfo.send_ctxt = uctxt->sc->hw_context;

        cinfo.egrtids = uctxt->egrbufs.alloced;
        cinfo.rcvhdrq_cnt = get_hdrq_cnt(uctxt);
        cinfo.rcvhdrq_entsize = get_hdrqentsize(uctxt) << 2;
        cinfo.sdma_ring_size = fd->cq->nentries;
        cinfo.rcvegr_size = uctxt->egrbufs.rcvtid_size;

        trace_hfi1_ctxt_info(uctxt->dd, uctxt->ctxt, fd->subctxt, &cinfo);
        if (copy_to_user((void __user *)arg, &cinfo, len))
                return -EFAULT;

        return 0;
}

static int init_user_ctxt(struct hfi1_filedata *fd,
                          struct hfi1_ctxtdata *uctxt)
{
        int ret;

        ret = hfi1_user_sdma_alloc_queues(uctxt, fd);
        if (ret)
                return ret;

        ret = hfi1_user_exp_rcv_init(fd, uctxt);
        if (ret)
                hfi1_user_sdma_free_queues(fd, uctxt);

        return ret;
}

static int setup_base_ctxt(struct hfi1_filedata *fd,
                           struct hfi1_ctxtdata *uctxt)
{
        struct hfi1_devdata *dd = uctxt->dd;
        int ret = 0;

        hfi1_init_ctxt(uctxt->sc);

        /* Now allocate the RcvHdr queue and eager buffers. */
        ret = hfi1_create_rcvhdrq(dd, uctxt);
        if (ret)
                goto done;

        ret = hfi1_setup_eagerbufs(uctxt);
        if (ret)
                goto done;

        /* If sub-contexts are enabled, do the appropriate setup */
        if (uctxt->subctxt_cnt)
                ret = setup_subctxt(uctxt);
        if (ret)
                goto done;

        ret = hfi1_alloc_ctxt_rcv_groups(uctxt);
        if (ret)
                goto done;

        ret = init_user_ctxt(fd, uctxt);
        if (ret)
                goto done;

        user_init(uctxt);

        /* Now that the context is set up, the fd can get a reference. */
        fd->uctxt = uctxt;
        hfi1_rcd_get(uctxt);

done:
        if (uctxt->subctxt_cnt) {
                /*
                 * On error, set the failed bit so sub-contexts will clean up
                 * correctly.
                 */
                if (ret)
                        set_bit(HFI1_CTXT_BASE_FAILED, &uctxt->event_flags);

                /*
                 * Base context is done (successfully or not), notify anybody
                 * using a sub-context that is waiting for this completion.
                 */
                clear_bit(HFI1_CTXT_BASE_UNINIT, &uctxt->event_flags);
                wake_up(&uctxt->wait);
        }

        return ret;
}

static int get_base_info(struct hfi1_filedata *fd, unsigned long arg, u32 len)
{
        struct hfi1_base_info binfo;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;
        struct hfi1_devdata *dd = uctxt->dd;
        unsigned offset;

        trace_hfi1_uctxtdata(uctxt->dd, uctxt, fd->subctxt);

        if (sizeof(binfo) != len)
                return -EINVAL;

        memset(&binfo, 0, sizeof(binfo));
        binfo.hw_version = dd->revision;
        binfo.sw_version = HFI1_KERN_SWVERSION;
        binfo.bthqp = kdeth_qp;
        binfo.jkey = uctxt->jkey;
        /*
         * If more than 64 contexts are enabled the allocated credit
         * return will span two or three contiguous pages. Since we only
         * map the page containing the context's credit return address,
         * we need to calculate the offset in the proper page.
         */
        offset = ((u64)uctxt->sc->hw_free -
                  (u64)dd->cr_base[uctxt->numa_id].va) % PAGE_SIZE;
        binfo.sc_credits_addr = HFI1_MMAP_TOKEN(PIO_CRED, uctxt->ctxt,
                                                fd->subctxt, offset);
        binfo.pio_bufbase = HFI1_MMAP_TOKEN(PIO_BUFS, uctxt->ctxt,
                                            fd->subctxt,
                                            uctxt->sc->base_addr);
        binfo.pio_bufbase_sop = HFI1_MMAP_TOKEN(PIO_BUFS_SOP,
                                                uctxt->ctxt,
                                                fd->subctxt,
                                                uctxt->sc->base_addr);
        binfo.rcvhdr_bufbase = HFI1_MMAP_TOKEN(RCV_HDRQ, uctxt->ctxt,
                                               fd->subctxt,
                                               uctxt->rcvhdrq);
        binfo.rcvegr_bufbase = HFI1_MMAP_TOKEN(RCV_EGRBUF, uctxt->ctxt,
                                               fd->subctxt,
                                               uctxt->egrbufs.rcvtids[0].dma);
        binfo.sdma_comp_bufbase = HFI1_MMAP_TOKEN(SDMA_COMP, uctxt->ctxt,
                                                  fd->subctxt, 0);
        /*
         * user regs are at
         * (RXE_PER_CONTEXT_USER + (ctxt * RXE_PER_CONTEXT_SIZE))
         */
        binfo.user_regbase = HFI1_MMAP_TOKEN(UREGS, uctxt->ctxt,
                                             fd->subctxt, 0);
        offset = offset_in_page((uctxt_offset(uctxt) + fd->subctxt) *
                                sizeof(*dd->events));
        binfo.events_bufbase = HFI1_MMAP_TOKEN(EVENTS, uctxt->ctxt,
                                               fd->subctxt,
                                               offset);
        binfo.status_bufbase = HFI1_MMAP_TOKEN(STATUS, uctxt->ctxt,
                                               fd->subctxt,
                                               dd->status);
        if (HFI1_CAP_IS_USET(DMA_RTAIL))
                binfo.rcvhdrtail_base = HFI1_MMAP_TOKEN(RTAIL, uctxt->ctxt,
                                                        fd->subctxt, 0);
        if (uctxt->subctxt_cnt) {
                binfo.subctxt_uregbase = HFI1_MMAP_TOKEN(SUBCTXT_UREGS,
                                                         uctxt->ctxt,
                                                         fd->subctxt, 0);
                binfo.subctxt_rcvhdrbuf = HFI1_MMAP_TOKEN(SUBCTXT_RCV_HDRQ,
                                                          uctxt->ctxt,
                                                          fd->subctxt, 0);
                binfo.subctxt_rcvegrbuf = HFI1_MMAP_TOKEN(SUBCTXT_EGRBUF,
                                                          uctxt->ctxt,
                                                          fd->subctxt, 0);
        }

        if (copy_to_user((void __user *)arg, &binfo, len))
                return -EFAULT;

        return 0;
}

/**
 * user_exp_rcv_setup - Set up the given tid rcv list
 * @fd: file data of the current driver instance
 * @arg: ioctl argumnent for user space information
 * @len: length of data structure associated with ioctl command
 *
 * Wrapper to validate ioctl information before doing _rcv_setup.
 *
 */
static int user_exp_rcv_setup(struct hfi1_filedata *fd, unsigned long arg,
                              u32 len)
{
        int ret;
        unsigned long addr;
        struct hfi1_tid_info tinfo;

        if (sizeof(tinfo) != len)
                return -EINVAL;

        if (copy_from_user(&tinfo, (void __user *)arg, (sizeof(tinfo))))
                return -EFAULT;

        ret = hfi1_user_exp_rcv_setup(fd, &tinfo);
        if (!ret) {
                /*
                 * Copy the number of tidlist entries we used
                 * and the length of the buffer we registered.
                 */
                addr = arg + offsetof(struct hfi1_tid_info, tidcnt);
                if (copy_to_user((void __user *)addr, &tinfo.tidcnt,
                                 sizeof(tinfo.tidcnt)))
                        return -EFAULT;

                addr = arg + offsetof(struct hfi1_tid_info, length);
                if (copy_to_user((void __user *)addr, &tinfo.length,
                                 sizeof(tinfo.length)))
                        ret = -EFAULT;
        }

        return ret;
}

/**
 * user_exp_rcv_clear - Clear the given tid rcv list
 * @fd: file data of the current driver instance
 * @arg: ioctl argumnent for user space information
 * @len: length of data structure associated with ioctl command
 *
 * The hfi1_user_exp_rcv_clear() can be called from the error path.  Because
 * of this, we need to use this wrapper to copy the user space information
 * before doing the clear.
 */
static int user_exp_rcv_clear(struct hfi1_filedata *fd, unsigned long arg,
                              u32 len)
{
        int ret;
        unsigned long addr;
        struct hfi1_tid_info tinfo;

        if (sizeof(tinfo) != len)
                return -EINVAL;

        if (copy_from_user(&tinfo, (void __user *)arg, (sizeof(tinfo))))
                return -EFAULT;

        ret = hfi1_user_exp_rcv_clear(fd, &tinfo);
        if (!ret) {
                addr = arg + offsetof(struct hfi1_tid_info, tidcnt);
                if (copy_to_user((void __user *)addr, &tinfo.tidcnt,
                                 sizeof(tinfo.tidcnt)))
                        return -EFAULT;
        }

        return ret;
}

/**
 * user_exp_rcv_invalid - Invalidate the given tid rcv list
 * @fd: file data of the current driver instance
 * @arg: ioctl argumnent for user space information
 * @len: length of data structure associated with ioctl command
 *
 * Wrapper to validate ioctl information before doing _rcv_invalid.
 *
 */
static int user_exp_rcv_invalid(struct hfi1_filedata *fd, unsigned long arg,
                                u32 len)
{
        int ret;
        unsigned long addr;
        struct hfi1_tid_info tinfo;

        if (sizeof(tinfo) != len)
                return -EINVAL;

        if (!fd->invalid_tids)
                return -EINVAL;

        if (copy_from_user(&tinfo, (void __user *)arg, (sizeof(tinfo))))
                return -EFAULT;

        ret = hfi1_user_exp_rcv_invalid(fd, &tinfo);
        if (ret)
                return ret;

        addr = arg + offsetof(struct hfi1_tid_info, tidcnt);
        if (copy_to_user((void __user *)addr, &tinfo.tidcnt,
                         sizeof(tinfo.tidcnt)))
                ret = -EFAULT;

        return ret;
}

static __poll_t poll_urgent(struct file *fp,
                                struct poll_table_struct *pt)
{
        struct hfi1_filedata *fd = fp->private_data;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;
        struct hfi1_devdata *dd = uctxt->dd;
        __poll_t pollflag;

        poll_wait(fp, &uctxt->wait, pt);

        spin_lock_irq(&dd->uctxt_lock);
        if (uctxt->urgent != uctxt->urgent_poll) {
                pollflag = EPOLLIN | EPOLLRDNORM;
                uctxt->urgent_poll = uctxt->urgent;
        } else {
                pollflag = 0;
                set_bit(HFI1_CTXT_WAITING_URG, &uctxt->event_flags);
        }
        spin_unlock_irq(&dd->uctxt_lock);

        return pollflag;
}

static __poll_t poll_next(struct file *fp,
                              struct poll_table_struct *pt)
{
        struct hfi1_filedata *fd = fp->private_data;
        struct hfi1_ctxtdata *uctxt = fd->uctxt;
        struct hfi1_devdata *dd = uctxt->dd;
        __poll_t pollflag;

        poll_wait(fp, &uctxt->wait, pt);

        spin_lock_irq(&dd->uctxt_lock);
        if (hdrqempty(uctxt)) {
                set_bit(HFI1_CTXT_WAITING_RCV, &uctxt->event_flags);
                hfi1_rcvctrl(dd, HFI1_RCVCTRL_INTRAVAIL_ENB, uctxt);
                pollflag = 0;
        } else {
                pollflag = EPOLLIN | EPOLLRDNORM;
        }
        spin_unlock_irq(&dd->uctxt_lock);

        return pollflag;
}

/*
 * Find all user contexts in use, and set the specified bit in their
 * event mask.
 * See also find_ctxt() for a similar use, that is specific to send buffers.
 */
int hfi1_set_uevent_bits(struct hfi1_pportdata *ppd, const int evtbit)
{
        struct hfi1_ctxtdata *uctxt;
        struct hfi1_devdata *dd = ppd->dd;
        u16 ctxt;

        if (!dd->events)
                return -EINVAL;

        for (ctxt = dd->first_dyn_alloc_ctxt; ctxt < dd->num_rcv_contexts;
             ctxt++) {
                uctxt = hfi1_rcd_get_by_index(dd, ctxt);
                if (uctxt) {
                        unsigned long *evs;
                        int i;
                        /*
                         * subctxt_cnt is 0 if not shared, so do base
                         * separately, first, then remaining subctxt, if any
                         */
                        evs = dd->events + uctxt_offset(uctxt);
                        set_bit(evtbit, evs);
                        for (i = 1; i < uctxt->subctxt_cnt; i++)
                                set_bit(evtbit, evs + i);
                        hfi1_rcd_put(uctxt);
                }
        }

        return 0;
}

/**
 * manage_rcvq - manage a context's receive queue
 * @uctxt: the context
 * @subctxt: the sub-context
 * @start_stop: action to carry out
 *
 * start_stop == 0 disables receive on the context, for use in queue
 * overflow conditions.  start_stop==1 re-enables, to be used to
 * re-init the software copy of the head register
 */
static int manage_rcvq(struct hfi1_ctxtdata *uctxt, u16 subctxt,
                       unsigned long arg)
{
        struct hfi1_devdata *dd = uctxt->dd;
        unsigned int rcvctrl_op;
        int start_stop;

        if (subctxt)
                return 0;

        if (get_user(start_stop, (int __user *)arg))
                return -EFAULT;

        /* atomically clear receive enable ctxt. */
        if (start_stop) {
                /*
                 * On enable, force in-memory copy of the tail register to
                 * 0, so that protocol code doesn't have to worry about
                 * whether or not the chip has yet updated the in-memory
                 * copy or not on return from the system call. The chip
                 * always resets it's tail register back to 0 on a
                 * transition from disabled to enabled.
                 */
                if (hfi1_rcvhdrtail_kvaddr(uctxt))
                        clear_rcvhdrtail(uctxt);
                rcvctrl_op = HFI1_RCVCTRL_CTXT_ENB;
        } else {
                rcvctrl_op = HFI1_RCVCTRL_CTXT_DIS;
        }
        hfi1_rcvctrl(dd, rcvctrl_op, uctxt);
        /* always; new head should be equal to new tail; see above */

        return 0;
}

/*
 * clear the event notifier events for this context.
 * User process then performs actions appropriate to bit having been
 * set, if desired, and checks again in future.
 */
static int user_event_ack(struct hfi1_ctxtdata *uctxt, u16 subctxt,
                          unsigned long arg)
{
        int i;
        struct hfi1_devdata *dd = uctxt->dd;
        unsigned long *evs;
        unsigned long events;

        if (!dd->events)
                return 0;

        if (get_user(events, (unsigned long __user *)arg))
                return -EFAULT;

        evs = dd->events + uctxt_offset(uctxt) + subctxt;

        for (i = 0; i <= _HFI1_MAX_EVENT_BIT; i++) {
                if (!test_bit(i, &events))
                        continue;
                clear_bit(i, evs);
        }
        return 0;
}

static int set_ctxt_pkey(struct hfi1_ctxtdata *uctxt, unsigned long arg)
{
        int i;
        struct hfi1_pportdata *ppd = uctxt->ppd;
        struct hfi1_devdata *dd = uctxt->dd;
        u16 pkey;

        if (!HFI1_CAP_IS_USET(PKEY_CHECK))
                return -EPERM;

        if (get_user(pkey, (u16 __user *)arg))
                return -EFAULT;

        if (pkey == LIM_MGMT_P_KEY || pkey == FULL_MGMT_P_KEY)
                return -EINVAL;

        for (i = 0; i < ARRAY_SIZE(ppd->pkeys); i++)
                if (pkey == ppd->pkeys[i])
                        return hfi1_set_ctxt_pkey(dd, uctxt, pkey);

        return -ENOENT;
}

/**
 * ctxt_reset - Reset the user context
 * @uctxt: valid user context
 */
static int ctxt_reset(struct hfi1_ctxtdata *uctxt)
{
        struct send_context *sc;
        struct hfi1_devdata *dd;
        int ret = 0;

        if (!uctxt || !uctxt->dd || !uctxt->sc)
                return -EINVAL;

        /*
         * There is no protection here. User level has to guarantee that
         * no one will be writing to the send context while it is being
         * re-initialized.  If user level breaks that guarantee, it will
         * break it's own context and no one else's.
         */
        dd = uctxt->dd;
        sc = uctxt->sc;

        /*
         * Wait until the interrupt handler has marked the context as
         * halted or frozen. Report error if we time out.
         */
        wait_event_interruptible_timeout(
                sc->halt_wait, (sc->flags & SCF_HALTED),
                msecs_to_jiffies(SEND_CTXT_HALT_TIMEOUT));
        if (!(sc->flags & SCF_HALTED))
                return -ENOLCK;

        /*
         * If the send context was halted due to a Freeze, wait until the
         * device has been "unfrozen" before resetting the context.
         */
        if (sc->flags & SCF_FROZEN) {
                wait_event_interruptible_timeout(
                        dd->event_queue,
                        !(READ_ONCE(dd->flags) & HFI1_FROZEN),
                        msecs_to_jiffies(SEND_CTXT_HALT_TIMEOUT));
                if (dd->flags & HFI1_FROZEN)
                        return -ENOLCK;

                if (dd->flags & HFI1_FORCED_FREEZE)
                        /*
                         * Don't allow context reset if we are into
                         * forced freeze
                         */
                        return -ENODEV;

                sc_disable(sc);
                ret = sc_enable(sc);
                hfi1_rcvctrl(dd, HFI1_RCVCTRL_CTXT_ENB, uctxt);
        } else {
                ret = sc_restart(sc);
        }
        if (!ret)
                sc_return_credits(sc);

        return ret;
}

static void user_remove(struct hfi1_devdata *dd)
{

        hfi1_cdev_cleanup(&dd->user_cdev, &dd->user_device);
}

static int user_add(struct hfi1_devdata *dd)
{
        char name[10];
        int ret;

        snprintf(name, sizeof(name), "%s_%d", class_name(), dd->unit);
        ret = hfi1_cdev_init(dd->unit, name, &hfi1_file_ops,
                             &dd->user_cdev, &dd->user_device,
                             true, &dd->kobj);
        if (ret)
                user_remove(dd);

        return ret;
}

/*
 * Create per-unit files in /dev
 */
int hfi1_device_create(struct hfi1_devdata *dd)
{
        return user_add(dd);
}

/*
 * Remove per-unit files in /dev
 * void, core kernel returns no errors for this stuff
 */
void hfi1_device_remove(struct hfi1_devdata *dd)
{
        user_remove(dd);
}