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/gfp.h>
  24 #include <linux/file.h>
  25 #include <net/tcp.h>
  26 #include <scsi/scsi.h>
  27 #include <scsi/scsi_cmnd.h>
  28 #include <scsi/scsi_device.h>
  29 #include <scsi/scsi_host.h>
  30 #include <scsi/scsi_tgt.h>
  31 #include <scsi/scsi_tgt_if.h>
  32
  33 #include <asm/cacheflush.h>
  34
  35 #include "scsi_tgt_priv.h"
  36
  37 #if TGT_RING_SIZE < PAGE_SIZE
  38 #  define TGT_RING_SIZE PAGE_SIZE
  39 #endif
  40
  41 #define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
  42 #define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
  43 #define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
  44
  45 struct tgt_ring {
  46         u32 tr_idx;
  47         unsigned long tr_pages[TGT_RING_PAGES];
  48         spinlock_t tr_lock;
  49 };
  50
  51 /* tx_ring : kernel->user, rx_ring : user->kernel */
  52 static struct tgt_ring tx_ring, rx_ring;
  53 static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);
  54
  55 static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
  56 {
  57         if (ring->tr_idx == TGT_MAX_EVENTS - 1)
  58                 ring->tr_idx = 0;
  59         else
  60                 ring->tr_idx++;
  61 }
  62
  63 static struct tgt_event *tgt_head_event(struct tgt_ring *ring, u32 idx)
  64 {
  65         u32 pidx, off;
  66
  67         pidx = idx / TGT_EVENT_PER_PAGE;
  68         off = idx % TGT_EVENT_PER_PAGE;
  69
  70         return (struct tgt_event *)
  71                 (ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
  72 }
  73
  74 static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
  75 {
  76         struct tgt_event *ev;
  77         struct tgt_ring *ring = &tx_ring;
  78         unsigned long flags;
  79         int err = 0;
  80
  81         spin_lock_irqsave(&ring->tr_lock, flags);
  82
  83         ev = tgt_head_event(ring, ring->tr_idx);
  84         if (!ev->hdr.status)
  85                 tgt_ring_idx_inc(ring);
  86         else
  87                 err = -BUSY;
  88
  89         spin_unlock_irqrestore(&ring->tr_lock, flags);
  90
  91         if (err)
  92                 return err;
  93
  94         memcpy(ev, p, sizeof(*ev));
  95         ev->hdr.type = type;
  96         mb();
  97         ev->hdr.status = 1;
  98
  99         flush_dcache_page(virt_to_page(ev));
 100
 101         wake_up_interruptible(&tgt_poll_wait);
 102
 103         return 0;
 104 }
 105
 106 int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 itn_id,
 107                              struct scsi_lun *lun, u64 tag)
 108 {
 109         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 110         struct tgt_event ev;
 111         int err;
 112
 113         memset(&ev, 0, sizeof(ev));
 114         ev.p.cmd_req.host_no = shost->host_no;
 115         ev.p.cmd_req.itn_id = itn_id;
 116         ev.p.cmd_req.data_len = scsi_bufflen(cmd);
 117         memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
 118         memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
 119         ev.p.cmd_req.attribute = cmd->tag;
 120         ev.p.cmd_req.tag = tag;
 121
 122         dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
 123                 ev.p.cmd_req.data_len, cmd->tag,
 124                 (unsigned long long) ev.p.cmd_req.tag);
 125
 126         err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
 127         if (err)
 128                 eprintk("tx buf is full, could not send\n");
 129
 130         return err;
 131 }
 132
 133 int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 itn_id, u64 tag)
 134 {
 135         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
 136         struct tgt_event ev;
 137         int err;
 138
 139         memset(&ev, 0, sizeof(ev));
 140         ev.p.cmd_done.host_no = shost->host_no;
 141         ev.p.cmd_done.itn_id = itn_id;
 142         ev.p.cmd_done.tag = tag;
 143         ev.p.cmd_done.result = cmd->result;
 144
 145         dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
 146                 (unsigned long long) ev.p.cmd_req.tag,
 147                 ev.p.cmd_req.data_len, cmd->tag);
 148
 149         err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
 150         if (err)
 151                 eprintk("tx buf is full, could not send\n");
 152
 153         return err;
 154 }
 155
 156 int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 itn_id, int function,
 157                                   u64 tag, struct scsi_lun *scsilun, void *data)
 158 {
 159         struct tgt_event ev;
 160         int err;
 161
 162         memset(&ev, 0, sizeof(ev));
 163         ev.p.tsk_mgmt_req.host_no = host_no;
 164         ev.p.tsk_mgmt_req.itn_id = itn_id;
 165         ev.p.tsk_mgmt_req.function = function;
 166         ev.p.tsk_mgmt_req.tag = tag;
 167         memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
 168         ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;
 169
 170         dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
 171                 (unsigned long long) ev.p.tsk_mgmt_req.mid);
 172
 173         err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
 174         if (err)
 175                 eprintk("tx buf is full, could not send\n");
 176
 177         return err;
 178 }
 179
 180 int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 itn_id,
 181                                           int function, char *initiator_id)
 182 {
 183         struct tgt_event ev;
 184         int err;
 185
 186         memset(&ev, 0, sizeof(ev));
 187         ev.p.it_nexus_req.host_no = host_no;
 188         ev.p.it_nexus_req.function = function;
 189         ev.p.it_nexus_req.itn_id = itn_id;
 190         if (initiator_id)
 191                 strncpy(ev.p.it_nexus_req.initiator_id, initiator_id,
 192                         sizeof(ev.p.it_nexus_req.initiator_id));
 193
 194         dprintk("%d %x %llx\n", host_no, function, (unsigned long long)itn_id);
 195
 196         err = tgt_uspace_send_event(TGT_KEVENT_IT_NEXUS_REQ, &ev);
 197         if (err)
 198                 eprintk("tx buf is full, could not send\n");
 199
 200         return err;
 201 }
 202
 203 static int event_recv_msg(struct tgt_event *ev)
 204 {
 205         int err = 0;
 206
 207         switch (ev->hdr.type) {
 208         case TGT_UEVENT_CMD_RSP:
 209                 err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
 210                                            ev->p.cmd_rsp.itn_id,
 211                                            ev->p.cmd_rsp.result,
 212                                            ev->p.cmd_rsp.tag,
 213                                            ev->p.cmd_rsp.uaddr,
 214                                            ev->p.cmd_rsp.len,
 215                                            ev->p.cmd_rsp.sense_uaddr,
 216                                            ev->p.cmd_rsp.sense_len,
 217                                            ev->p.cmd_rsp.rw);
 218                 break;
 219         case TGT_UEVENT_TSK_MGMT_RSP:
 220                 err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
 221                                                ev->p.tsk_mgmt_rsp.itn_id,
 222                                                ev->p.tsk_mgmt_rsp.mid,
 223                                                ev->p.tsk_mgmt_rsp.result);
 224                 break;
 225         case TGT_UEVENT_IT_NEXUS_RSP:
 226                 err = scsi_tgt_kspace_it_nexus_rsp(ev->p.it_nexus_rsp.host_no,
 227                                                    ev->p.it_nexus_rsp.itn_id,
 228                                                    ev->p.it_nexus_rsp.result);
 229                 break;
 230         default:
 231                 eprintk("unknown type %d\n", ev->hdr.type);
 232                 err = -EINVAL;
 233         }
 234
 235         return err;
 236 }
 237
 238 static ssize_t tgt_write(struct file *file, const char __user * buffer,
 239                          size_t count, loff_t * ppos)
 240 {
 241         struct tgt_event *ev;
 242         struct tgt_ring *ring = &rx_ring;
 243
 244         while (1) {
 245                 ev = tgt_head_event(ring, ring->tr_idx);
 246                 /* do we need this? */
 247                 flush_dcache_page(virt_to_page(ev));
 248
 249                 if (!ev->hdr.status)
 250                         break;
 251
 252                 tgt_ring_idx_inc(ring);
 253                 event_recv_msg(ev);
 254                 ev->hdr.status = 0;
 255         };
 256
 257         return count;
 258 }
 259
 260 static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
 261 {
 262         struct tgt_event *ev;
 263         struct tgt_ring *ring = &tx_ring;
 264         unsigned long flags;
 265         unsigned int mask = 0;
 266         u32 idx;
 267
 268         poll_wait(file, &tgt_poll_wait, wait);
 269
 270         spin_lock_irqsave(&ring->tr_lock, flags);
 271
 272         idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
 273         ev = tgt_head_event(ring, idx);
 274         if (ev->hdr.status)
 275                 mask |= POLLIN | POLLRDNORM;
 276
 277         spin_unlock_irqrestore(&ring->tr_lock, flags);
 278
 279         return mask;
 280 }
 281
 282 static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
 283                            struct tgt_ring *ring)
 284 {
 285         int i, err;
 286
 287         for (i = 0; i < TGT_RING_PAGES; i++) {
 288                 struct page *page = virt_to_page(ring->tr_pages[i]);
 289                 err = vm_insert_page(vma, addr, page);
 290                 if (err)
 291                         return err;
 292                 addr += PAGE_SIZE;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int tgt_mmap(struct file *filp, struct vm_area_struct *vma)
 299 {
 300         unsigned long addr;
 301         int err;
 302
 303         if (vma->vm_pgoff)
 304                 return -EINVAL;
 305
 306         if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
 307                 eprintk("mmap size must be %lu, not %lu \n",
 308                         TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
 309                 return -EINVAL;
 310         }
 311
 312         addr = vma->vm_start;
 313         err = uspace_ring_map(vma, addr, &tx_ring);
 314         if (err)
 315                 return err;
 316         err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);
 317
 318         return err;
 319 }
 320
 321 static int tgt_open(struct inode *inode, struct file *file)
 322 {
 323         tx_ring.tr_idx = rx_ring.tr_idx = 0;
 324
 325         return 0;
 326 }
 327
 328 static const struct file_operations tgt_fops = {
 329         .owner          = THIS_MODULE,
 330         .open           = tgt_open,
 331         .poll           = tgt_poll,
 332         .write          = tgt_write,
 333         .mmap           = tgt_mmap,
 334         .llseek         = noop_llseek,
 335 };
 336
 337 static struct miscdevice tgt_miscdev = {
 338         .minor = MISC_DYNAMIC_MINOR,
 339         .name = "tgt",
 340         .fops = &tgt_fops,
 341 };
 342
 343 static void tgt_ring_exit(struct tgt_ring *ring)
 344 {
 345         int i;
 346
 347         for (i = 0; i < TGT_RING_PAGES; i++)
 348                 free_page(ring->tr_pages[i]);
 349 }
 350
 351 static int tgt_ring_init(struct tgt_ring *ring)
 352 {
 353         int i;
 354
 355         spin_lock_init(&ring->tr_lock);
 356
 357         for (i = 0; i < TGT_RING_PAGES; i++) {
 358                 ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
 359                 if (!ring->tr_pages[i]) {
 360                         eprintk("out of memory\n");
 361                         return -ENOMEM;
 362                 }
 363         }
 364
 365         return 0;
 366 }
 367
 368 void scsi_tgt_if_exit(void)
 369 {
 370         tgt_ring_exit(&tx_ring);
 371         tgt_ring_exit(&rx_ring);
 372         misc_deregister(&tgt_miscdev);
 373 }
 374
 375 int scsi_tgt_if_init(void)
 376 {
 377         int err;
 378
 379         err = tgt_ring_init(&tx_ring);
 380         if (err)
 381                 return err;
 382
 383         err = tgt_ring_init(&rx_ring);
 384         if (err)
 385                 goto free_tx_ring;
 386
 387         err = misc_register(&tgt_miscdev);
 388         if (err)
 389                 goto free_rx_ring;
 390
 391         return 0;
 392 free_rx_ring:
 393         tgt_ring_exit(&rx_ring);
 394 free_tx_ring:
 395         tgt_ring_exit(&tx_ring);
 396
 397         return err;
 398 }