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