drivers/scsi/scsi_tgt_if.c

   1 /*
   2  * SCSI target kernel/user interface functions
   3  *
   4  * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
   5  * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  20  * 02110-1301 USA
  21  */
  22 #include <linux/miscdevice.h>
  23 #include <linux/file.h>
  24 #include <net/tcp.h>
  25 #include <scsi/scsi.h>
  26 #include <scsi/scsi_cmnd.h>
  27 #include <scsi/scsi_device.h>
  28 #include <scsi/scsi_host.h>
  29 #include <scsi/scsi_tgt.h>
  30 #include <scsi/scsi_tgt_if.h>
  31
  32 #include <asm/cacheflush.h>
  33
  34 #include "scsi_tgt_priv.h"
  35
  36 #if TGT_RING_SIZE < PAGE_SIZE
  37 #  define TGT_RING_SIZE PAGE_SIZE
  38 #endif
  39
  40 #define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
  41 #define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
  42 #define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
  43
  44 struct tgt_ring {
  45         u32 tr_idx;
  46         unsigned long tr_pages[TGT_RING_PAGES];
  47         spinlock_t tr_lock;
  48 };
  49
  50 /* tx_ring : kernel->user, rx_ring : user->kernel */
  51 static struct tgt_ring tx_ring, rx_ring;
  52 static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);
  53
  54 static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
  55 {
  56         if (ring->tr_idx == TGT_MAX_EVENTS - 1)
  57                 ring->tr_idx = 0;
  58         else
  59                 ring->tr_idx++;
  60 }
  61
  62 static struct tgt_event *tgt_head_event(struct tgt_ring *ring, u32 idx)
  63 {
  64         u32 pidx, off;
  65
  66         pidx = idx / TGT_EVENT_PER_PAGE;
  67         off = idx % TGT_EVENT_PER_PAGE;
  68
  69         return (struct tgt_event *)
  70                 (ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
  71 }
  72
  73 static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
  74 {
  75         struct tgt_event *ev;
  76         struct tgt_ring *ring = &tx_ring;
  77         unsigned long flags;
  78         int err = 0;
  79
  80         spin_lock_irqsave(&ring->tr_lock, flags);
  81
  82         ev = tgt_head_event(ring, ring->tr_idx);
  83         if (!ev->hdr.status)
  84                 tgt_ring_idx_inc(ring);
  85         else
  86                 err = -BUSY;
  87
  88         spin_unlock_irqrestore(&ring->tr_lock, flags);
  89
  90         if (err)
  91                 return err;
  92
  93         memcpy(ev, p, sizeof(*ev));
  94         ev->hdr.type = type;
  95         mb();
  96         ev->hdr.status = 1;
  97
  98         flush_dcache_page(virt_to_page(ev));
  99
 100         wake_up_interruptible(&tgt_poll_wait);
 101
 102         return 0;
 103 }
 104
 105 int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 tag)
 106 {
 107         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 108         struct tgt_event ev;
 109         int err;
 110
 111         memset(&ev, 0, sizeof(ev));
 112         ev.p.cmd_req.host_no = shost->host_no;
 113         ev.p.cmd_req.data_len = cmd->request_bufflen;
 114         memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
 115         memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
 116         ev.p.cmd_req.attribute = cmd->tag;
 117         ev.p.cmd_req.tag = tag;
 118
 119         dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
 120                 ev.p.cmd_req.data_len, cmd->tag,
 121                 (unsigned long long) ev.p.cmd_req.tag);
 122
 123         err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
 124         if (err)
 125                 eprintk("tx buf is full, could not send\n");
 126
 127         return err;
 128 }
 129
 130 int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
 131 {
 132         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 133         struct tgt_event ev;
 134         int err;
 135
 136         memset(&ev, 0, sizeof(ev));
 137         ev.p.cmd_done.host_no = shost->host_no;
 138         ev.p.cmd_done.tag = tag;
 139         ev.p.cmd_done.result = cmd->result;
 140
 141         dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
 142                 (unsigned long long) ev.p.cmd_req.tag,
 143                 ev.p.cmd_req.data_len, cmd->tag);
 144
 145         err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
 146         if (err)
 147                 eprintk("tx buf is full, could not send\n");
 148
 149         return err;
 150 }
 151
 152 int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
 153                                   struct scsi_lun *scsilun, void *data)
 154 {
 155         struct tgt_event ev;
 156         int err;
 157
 158         memset(&ev, 0, sizeof(ev));
 159         ev.p.tsk_mgmt_req.host_no = host_no;
 160         ev.p.tsk_mgmt_req.function = function;
 161         ev.p.tsk_mgmt_req.tag = tag;
 162         memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
 163         ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;
 164
 165         dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
 166                 (unsigned long long) ev.p.tsk_mgmt_req.mid);
 167
 168         err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
 169         if (err)
 170                 eprintk("tx buf is full, could not send\n");
 171
 172         return err;
 173 }
 174
 175 static int event_recv_msg(struct tgt_event *ev)
 176 {
 177         int err = 0;
 178
 179         switch (ev->hdr.type) {
 180         case TGT_UEVENT_CMD_RSP:
 181                 err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
 182                                            ev->p.cmd_rsp.result,
 183                                            ev->p.cmd_rsp.tag,
 184                                            ev->p.cmd_rsp.uaddr,
 185                                            ev->p.cmd_rsp.len,
 186                                            ev->p.cmd_rsp.sense_uaddr,
 187                                            ev->p.cmd_rsp.sense_len,
 188                                            ev->p.cmd_rsp.rw);
 189                 break;
 190         case TGT_UEVENT_TSK_MGMT_RSP:
 191                 err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
 192                                                ev->p.tsk_mgmt_rsp.mid,
 193                                                ev->p.tsk_mgmt_rsp.result);
 194                 break;
 195         default:
 196                 eprintk("unknown type %d\n", ev->hdr.type);
 197                 err = -EINVAL;
 198         }
 199
 200         return err;
 201 }
 202
 203 static ssize_t tgt_write(struct file *file, const char __user * buffer,
 204                          size_t count, loff_t * ppos)
 205 {
 206         struct tgt_event *ev;
 207         struct tgt_ring *ring = &rx_ring;
 208
 209         while (1) {
 210                 ev = tgt_head_event(ring, ring->tr_idx);
 211                 /* do we need this? */
 212                 flush_dcache_page(virt_to_page(ev));
 213
 214                 if (!ev->hdr.status)
 215                         break;
 216
 217                 tgt_ring_idx_inc(ring);
 218                 event_recv_msg(ev);
 219                 ev->hdr.status = 0;
 220         };
 221
 222         return count;
 223 }
 224
 225 static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
 226 {
 227         struct tgt_event *ev;
 228         struct tgt_ring *ring = &tx_ring;
 229         unsigned long flags;
 230         unsigned int mask = 0;
 231         u32 idx;
 232
 233         poll_wait(file, &tgt_poll_wait, wait);
 234
 235         spin_lock_irqsave(&ring->tr_lock, flags);
 236
 237         idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
 238         ev = tgt_head_event(ring, idx);
 239         if (ev->hdr.status)
 240                 mask |= POLLIN | POLLRDNORM;
 241
 242         spin_unlock_irqrestore(&ring->tr_lock, flags);
 243
 244         return mask;
 245 }
 246
 247 static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
 248                            struct tgt_ring *ring)
 249 {
 250         int i, err;
 251
 252         for (i = 0; i < TGT_RING_PAGES; i++) {
 253                 struct page *page = virt_to_page(ring->tr_pages[i]);
 254                 err = vm_insert_page(vma, addr, page);
 255                 if (err)
 256                         return err;
 257                 addr += PAGE_SIZE;
 258         }
 259
 260         return 0;
 261 }
 262
 263 static int tgt_mmap(struct file *filp, struct vm_area_struct *vma)
 264 {
 265         unsigned long addr;
 266         int err;
 267
 268         if (vma->vm_pgoff)
 269                 return -EINVAL;
 270
 271         if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
 272                 eprintk("mmap size must be %lu, not %lu \n",
 273                         TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
 274                 return -EINVAL;
 275         }
 276
 277         addr = vma->vm_start;
 278         err = uspace_ring_map(vma, addr, &tx_ring);
 279         if (err)
 280                 return err;
 281         err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);
 282
 283         return err;
 284 }
 285
 286 static int tgt_open(struct inode *inode, struct file *file)
 287 {
 288         tx_ring.tr_idx = rx_ring.tr_idx = 0;
 289
 290         return 0;
 291 }
 292
 293 static const struct file_operations tgt_fops = {
 294         .owner          = THIS_MODULE,
 295         .open           = tgt_open,
 296         .poll           = tgt_poll,
 297         .write          = tgt_write,
 298         .mmap           = tgt_mmap,
 299 };
 300
 301 static struct miscdevice tgt_miscdev = {
 302         .minor = MISC_DYNAMIC_MINOR,
 303         .name = "tgt",
 304         .fops = &tgt_fops,
 305 };
 306
 307 static void tgt_ring_exit(struct tgt_ring *ring)
 308 {
 309         int i;
 310
 311         for (i = 0; i < TGT_RING_PAGES; i++)
 312                 free_page(ring->tr_pages[i]);
 313 }
 314
 315 static int tgt_ring_init(struct tgt_ring *ring)
 316 {
 317         int i;
 318
 319         spin_lock_init(&ring->tr_lock);
 320
 321         for (i = 0; i < TGT_RING_PAGES; i++) {
 322                 ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
 323                 if (!ring->tr_pages[i]) {
 324                         eprintk("out of memory\n");
 325                         return -ENOMEM;
 326                 }
 327         }
 328
 329         return 0;
 330 }
 331
 332 void scsi_tgt_if_exit(void)
 333 {
 334         tgt_ring_exit(&tx_ring);
 335         tgt_ring_exit(&rx_ring);
 336         misc_deregister(&tgt_miscdev);
 337 }
 338
 339 int scsi_tgt_if_init(void)
 340 {
 341         int err;
 342
 343         err = tgt_ring_init(&tx_ring);
 344         if (err)
 345                 return err;
 346
 347         err = tgt_ring_init(&rx_ring);
 348         if (err)
 349                 goto free_tx_ring;
 350
 351         err = misc_register(&tgt_miscdev);
 352         if (err)
 353                 goto free_rx_ring;
 354
 355         return 0;
 356 free_rx_ring:
 357         tgt_ring_exit(&rx_ring);
 358 free_tx_ring:
 359         tgt_ring_exit(&tx_ring);
 360
 361         return err;
 362 }