1 /******************************************************************************
3 * Back-end of the driver for virtual block devices. This portion of the
4 * driver exports a 'unified' block-device interface that can be accessed
5 * by any operating system that implements a compatible front end. A
6 * reference front-end implementation can be found in:
7 * drivers/block/xen-blkfront.c
9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
10 * Copyright (c) 2005, Christopher Clark
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License version 2
14 * as published by the Free Software Foundation; or, when distributed
15 * separately from the Linux kernel or incorporated into other
16 * software packages, subject to the following license:
18 * Permission is hereby granted, free of charge, to any person obtaining a copy
19 * of this source file (the "Software"), to deal in the Software without
20 * restriction, including without limitation the rights to use, copy, modify,
21 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
22 * and to permit persons to whom the Software is furnished to do so, subject to
23 * the following conditions:
25 * The above copyright notice and this permission notice shall be included in
26 * all copies or substantial portions of the Software.
28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
29 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
31 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
32 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
33 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
37 #include <linux/spinlock.h>
38 #include <linux/kthread.h>
39 #include <linux/list.h>
40 #include <linux/delay.h>
41 #include <linux/freezer.h>
43 #include <xen/events.h>
46 #include <asm/xen/hypervisor.h>
47 #include <asm/xen/hypercall.h>
51 * These are rather arbitrary. They are fairly large because adjacent requests
52 * pulled from a communication ring are quite likely to end up being part of
53 * the same scatter/gather request at the disc.
55 * ** TRY INCREASING 'xen_blkif_reqs' IF WRITE SPEEDS SEEM TOO LOW **
57 * This will increase the chances of being able to write whole tracks.
58 * 64 should be enough to keep us competitive with Linux.
60 static int xen_blkif_reqs = 64;
61 module_param_named(reqs, xen_blkif_reqs, int, 0);
62 MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate");
64 /* Run-time switchable: /sys/module/blkback/parameters/ */
65 static unsigned int log_stats;
66 module_param(log_stats, int, 0644);
69 * Each outstanding request that we've passed to the lower device layers has a
70 * 'pending_req' allocated to it. Each buffer_head that completes decrements
71 * the pendcnt towards zero. When it hits zero, the specified domain has a
72 * response queued for it, with the saved 'id' passed back.
75 struct xen_blkif *blkif;
79 unsigned short operation;
81 struct list_head free_list;
84 #define BLKBACK_INVALID_HANDLE (~0)
87 struct pending_req *pending_reqs;
88 /* List of all 'pending_req' available */
89 struct list_head pending_free;
90 /* And its spinlock. */
91 spinlock_t pending_free_lock;
92 wait_queue_head_t pending_free_wq;
93 /* The list of all pages that are available. */
94 struct page **pending_pages;
95 /* And the grant handles that are available. */
96 grant_handle_t *pending_grant_handles;
99 static struct xen_blkbk *blkbk;
102 * Little helpful macro to figure out the index and virtual address of the
103 * pending_pages[..]. For each 'pending_req' we have have up to
104 * BLKIF_MAX_SEGMENTS_PER_REQUEST (11) pages. The seg would be from 0 through
105 * 10 and would index in the pending_pages[..].
107 static inline int vaddr_pagenr(struct pending_req *req, int seg)
109 return (req - blkbk->pending_reqs) *
110 BLKIF_MAX_SEGMENTS_PER_REQUEST + seg;
113 #define pending_page(req, seg) pending_pages[vaddr_pagenr(req, seg)]
115 static inline unsigned long vaddr(struct pending_req *req, int seg)
117 unsigned long pfn = page_to_pfn(blkbk->pending_page(req, seg));
118 return (unsigned long)pfn_to_kaddr(pfn);
121 #define pending_handle(_req, _seg) \
122 (blkbk->pending_grant_handles[vaddr_pagenr(_req, _seg)])
125 static int do_block_io_op(struct xen_blkif *blkif);
126 static int dispatch_rw_block_io(struct xen_blkif *blkif,
127 struct blkif_request *req,
128 struct pending_req *pending_req);
129 static void make_response(struct xen_blkif *blkif, u64 id,
130 unsigned short op, int st);
133 * Retrieve from the 'pending_reqs' a free pending_req structure to be used.
135 static struct pending_req *alloc_req(void)
137 struct pending_req *req = NULL;
140 spin_lock_irqsave(&blkbk->pending_free_lock, flags);
141 if (!list_empty(&blkbk->pending_free)) {
142 req = list_entry(blkbk->pending_free.next, struct pending_req,
144 list_del(&req->free_list);
146 spin_unlock_irqrestore(&blkbk->pending_free_lock, flags);
151 * Return the 'pending_req' structure back to the freepool. We also
152 * wake up the thread if it was waiting for a free page.
154 static void free_req(struct pending_req *req)
159 spin_lock_irqsave(&blkbk->pending_free_lock, flags);
160 was_empty = list_empty(&blkbk->pending_free);
161 list_add(&req->free_list, &blkbk->pending_free);
162 spin_unlock_irqrestore(&blkbk->pending_free_lock, flags);
164 wake_up(&blkbk->pending_free_wq);
168 * Routines for managing virtual block devices (vbds).
170 static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif,
173 struct xen_vbd *vbd = &blkif->vbd;
176 if ((operation != READ) && vbd->readonly)
179 if (likely(req->nr_sects)) {
180 blkif_sector_t end = req->sector_number + req->nr_sects;
182 if (unlikely(end < req->sector_number))
184 if (unlikely(end > vbd_sz(vbd)))
188 req->dev = vbd->pdevice;
189 req->bdev = vbd->bdev;
196 static void xen_vbd_resize(struct xen_blkif *blkif)
198 struct xen_vbd *vbd = &blkif->vbd;
199 struct xenbus_transaction xbt;
201 struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be);
202 unsigned long long new_size = vbd_sz(vbd);
204 pr_info(DRV_PFX "VBD Resize: Domid: %d, Device: (%d, %d)\n",
205 blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
206 pr_info(DRV_PFX "VBD Resize: new size %llu\n", new_size);
207 vbd->size = new_size;
209 err = xenbus_transaction_start(&xbt);
211 pr_warn(DRV_PFX "Error starting transaction");
214 err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
215 (unsigned long long)vbd_sz(vbd));
217 pr_warn(DRV_PFX "Error writing new size");
221 * Write the current state; we will use this to synchronize
222 * the front-end. If the current state is "connected" the
223 * front-end will get the new size information online.
225 err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
227 pr_warn(DRV_PFX "Error writing the state");
231 err = xenbus_transaction_end(xbt, 0);
235 pr_warn(DRV_PFX "Error ending transaction");
238 xenbus_transaction_end(xbt, 1);
242 * Notification from the guest OS.
244 static void blkif_notify_work(struct xen_blkif *blkif)
246 blkif->waiting_reqs = 1;
250 irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
252 blkif_notify_work(dev_id);
257 * SCHEDULER FUNCTIONS
260 static void print_stats(struct xen_blkif *blkif)
262 pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d"
264 current->comm, blkif->st_oo_req,
265 blkif->st_rd_req, blkif->st_wr_req,
266 blkif->st_f_req, blkif->st_ds_req);
267 blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000);
268 blkif->st_rd_req = 0;
269 blkif->st_wr_req = 0;
270 blkif->st_oo_req = 0;
271 blkif->st_ds_req = 0;
274 int xen_blkif_schedule(void *arg)
276 struct xen_blkif *blkif = arg;
277 struct xen_vbd *vbd = &blkif->vbd;
279 xen_blkif_get(blkif);
281 while (!kthread_should_stop()) {
284 if (unlikely(vbd->size != vbd_sz(vbd)))
285 xen_vbd_resize(blkif);
287 wait_event_interruptible(
289 blkif->waiting_reqs || kthread_should_stop());
290 wait_event_interruptible(
291 blkbk->pending_free_wq,
292 !list_empty(&blkbk->pending_free) ||
293 kthread_should_stop());
295 blkif->waiting_reqs = 0;
296 smp_mb(); /* clear flag *before* checking for work */
298 if (do_block_io_op(blkif))
299 blkif->waiting_reqs = 1;
301 if (log_stats && time_after(jiffies, blkif->st_print))
308 blkif->xenblkd = NULL;
309 xen_blkif_put(blkif);
319 * Unmap the grant references, and also remove the M2P over-rides
320 * used in the 'pending_req'.
322 static void xen_blkbk_unmap(struct pending_req *req)
324 struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
325 struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
326 unsigned int i, invcount = 0;
327 grant_handle_t handle;
330 for (i = 0; i < req->nr_pages; i++) {
331 handle = pending_handle(req, i);
332 if (handle == BLKBACK_INVALID_HANDLE)
334 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
335 GNTMAP_host_map, handle);
336 pending_handle(req, i) = BLKBACK_INVALID_HANDLE;
337 pages[invcount] = virt_to_page(vaddr(req, i));
341 ret = gnttab_unmap_refs(unmap, NULL, pages, invcount);
345 static int xen_blkbk_map(struct blkif_request *req,
346 struct pending_req *pending_req,
347 struct seg_buf seg[])
349 struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
351 int nseg = req->u.rw.nr_segments;
355 * Fill out preq.nr_sects with proper amount of sectors, and setup
356 * assign map[..] with the PFN of the page in our domain with the
357 * corresponding grant reference for each page.
359 for (i = 0; i < nseg; i++) {
362 flags = GNTMAP_host_map;
363 if (pending_req->operation != BLKIF_OP_READ)
364 flags |= GNTMAP_readonly;
365 gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
366 req->u.rw.seg[i].gref,
367 pending_req->blkif->domid);
370 ret = gnttab_map_refs(map, NULL, &blkbk->pending_page(pending_req, 0), nseg);
374 * Now swizzle the MFN in our domain with the MFN from the other domain
375 * so that when we access vaddr(pending_req,i) it has the contents of
376 * the page from the other domain.
378 for (i = 0; i < nseg; i++) {
379 if (unlikely(map[i].status != 0)) {
380 pr_debug(DRV_PFX "invalid buffer -- could not remap it\n");
381 map[i].handle = BLKBACK_INVALID_HANDLE;
385 pending_handle(pending_req, i) = map[i].handle;
390 seg[i].buf = map[i].dev_bus_addr |
391 (req->u.rw.seg[i].first_sect << 9);
396 static int dispatch_discard_io(struct xen_blkif *blkif,
397 struct blkif_request *req)
400 int status = BLKIF_RSP_OKAY;
401 struct block_device *bdev = blkif->vbd.bdev;
402 unsigned long secure;
406 xen_blkif_get(blkif);
407 secure = (blkif->vbd.discard_secure &&
408 (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
409 BLKDEV_DISCARD_SECURE : 0;
411 err = blkdev_issue_discard(bdev, req->u.discard.sector_number,
412 req->u.discard.nr_sectors,
415 if (err == -EOPNOTSUPP) {
416 pr_debug(DRV_PFX "discard op failed, not supported\n");
417 status = BLKIF_RSP_EOPNOTSUPP;
419 status = BLKIF_RSP_ERROR;
421 make_response(blkif, req->u.discard.id, req->operation, status);
422 xen_blkif_put(blkif);
426 static void xen_blk_drain_io(struct xen_blkif *blkif)
428 atomic_set(&blkif->drain, 1);
430 /* The initial value is one, and one refcnt taken at the
431 * start of the xen_blkif_schedule thread. */
432 if (atomic_read(&blkif->refcnt) <= 2)
434 wait_for_completion_interruptible_timeout(
435 &blkif->drain_complete, HZ);
437 if (!atomic_read(&blkif->drain))
439 } while (!kthread_should_stop());
440 atomic_set(&blkif->drain, 0);
444 * Completion callback on the bio's. Called as bh->b_end_io()
447 static void __end_block_io_op(struct pending_req *pending_req, int error)
449 /* An error fails the entire request. */
450 if ((pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE) &&
451 (error == -EOPNOTSUPP)) {
452 pr_debug(DRV_PFX "flush diskcache op failed, not supported\n");
453 xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0);
454 pending_req->status = BLKIF_RSP_EOPNOTSUPP;
455 } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
456 (error == -EOPNOTSUPP)) {
457 pr_debug(DRV_PFX "write barrier op failed, not supported\n");
458 xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0);
459 pending_req->status = BLKIF_RSP_EOPNOTSUPP;
461 pr_debug(DRV_PFX "Buffer not up-to-date at end of operation,"
462 " error=%d\n", error);
463 pending_req->status = BLKIF_RSP_ERROR;
467 * If all of the bio's have completed it is time to unmap
468 * the grant references associated with 'request' and provide
469 * the proper response on the ring.
471 if (atomic_dec_and_test(&pending_req->pendcnt)) {
472 xen_blkbk_unmap(pending_req);
473 make_response(pending_req->blkif, pending_req->id,
474 pending_req->operation, pending_req->status);
475 xen_blkif_put(pending_req->blkif);
476 if (atomic_read(&pending_req->blkif->refcnt) <= 2) {
477 if (atomic_read(&pending_req->blkif->drain))
478 complete(&pending_req->blkif->drain_complete);
480 free_req(pending_req);
487 static void end_block_io_op(struct bio *bio, int error)
489 __end_block_io_op(bio->bi_private, error);
496 * Function to copy the from the ring buffer the 'struct blkif_request'
497 * (which has the sectors we want, number of them, grant references, etc),
498 * and transmute it to the block API to hand it over to the proper block disk.
501 __do_block_io_op(struct xen_blkif *blkif)
503 union blkif_back_rings *blk_rings = &blkif->blk_rings;
504 struct blkif_request req;
505 struct pending_req *pending_req;
509 rc = blk_rings->common.req_cons;
510 rp = blk_rings->common.sring->req_prod;
511 rmb(); /* Ensure we see queued requests up to 'rp'. */
515 if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
518 if (kthread_should_stop()) {
523 pending_req = alloc_req();
524 if (NULL == pending_req) {
530 switch (blkif->blk_protocol) {
531 case BLKIF_PROTOCOL_NATIVE:
532 memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req));
534 case BLKIF_PROTOCOL_X86_32:
535 blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc));
537 case BLKIF_PROTOCOL_X86_64:
538 blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc));
543 blk_rings->common.req_cons = ++rc; /* before make_response() */
545 /* Apply all sanity checks to /private copy/ of request. */
547 if (unlikely(req.operation == BLKIF_OP_DISCARD)) {
548 free_req(pending_req);
549 if (dispatch_discard_io(blkif, &req))
551 } else if (dispatch_rw_block_io(blkif, &req, pending_req))
554 /* Yield point for this unbounded loop. */
562 do_block_io_op(struct xen_blkif *blkif)
564 union blkif_back_rings *blk_rings = &blkif->blk_rings;
568 more_to_do = __do_block_io_op(blkif);
572 RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
573 } while (more_to_do);
578 * Transmutation of the 'struct blkif_request' to a proper 'struct bio'
579 * and call the 'submit_bio' to pass it to the underlying storage.
581 static int dispatch_rw_block_io(struct xen_blkif *blkif,
582 struct blkif_request *req,
583 struct pending_req *pending_req)
585 struct phys_req preq;
586 struct seg_buf seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
588 struct bio *bio = NULL;
589 struct bio *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST];
592 struct blk_plug plug;
595 switch (req->operation) {
602 operation = WRITE_ODIRECT;
604 case BLKIF_OP_WRITE_BARRIER:
606 case BLKIF_OP_FLUSH_DISKCACHE:
608 operation = WRITE_FLUSH;
611 operation = 0; /* make gcc happy */
616 /* Check that the number of segments is sane. */
617 nseg = req->u.rw.nr_segments;
619 if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
620 unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
621 pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
623 /* Haven't submitted any bio's yet. */
627 preq.dev = req->u.rw.handle;
628 preq.sector_number = req->u.rw.sector_number;
631 pending_req->blkif = blkif;
632 pending_req->id = req->u.rw.id;
633 pending_req->operation = req->operation;
634 pending_req->status = BLKIF_RSP_OKAY;
635 pending_req->nr_pages = nseg;
637 for (i = 0; i < nseg; i++) {
638 seg[i].nsec = req->u.rw.seg[i].last_sect -
639 req->u.rw.seg[i].first_sect + 1;
640 if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
641 (req->u.rw.seg[i].last_sect < req->u.rw.seg[i].first_sect))
643 preq.nr_sects += seg[i].nsec;
647 if (xen_vbd_translate(&preq, blkif, operation) != 0) {
648 pr_debug(DRV_PFX "access denied: %s of [%llu,%llu] on dev=%04x\n",
649 operation == READ ? "read" : "write",
651 preq.sector_number + preq.nr_sects, preq.dev);
656 * This check _MUST_ be done after xen_vbd_translate as the preq.bdev
659 for (i = 0; i < nseg; i++) {
660 if (((int)preq.sector_number|(int)seg[i].nsec) &
661 ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
662 pr_debug(DRV_PFX "Misaligned I/O request from domain %d",
668 /* Wait on all outstanding I/O's and once that has been completed
669 * issue the WRITE_FLUSH.
672 xen_blk_drain_io(pending_req->blkif);
675 * If we have failed at this point, we need to undo the M2P override,
676 * set gnttab_set_unmap_op on all of the grant references and perform
677 * the hypercall to unmap the grants - that is all done in
680 if (xen_blkbk_map(req, pending_req, seg))
684 * This corresponding xen_blkif_put is done in __end_block_io_op, or
685 * below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
687 xen_blkif_get(blkif);
689 for (i = 0; i < nseg; i++) {
690 while ((bio == NULL) ||
692 blkbk->pending_page(pending_req, i),
694 seg[i].buf & ~PAGE_MASK) == 0)) {
696 bio = bio_alloc(GFP_KERNEL, nseg-i);
697 if (unlikely(bio == NULL))
700 biolist[nbio++] = bio;
701 bio->bi_bdev = preq.bdev;
702 bio->bi_private = pending_req;
703 bio->bi_end_io = end_block_io_op;
704 bio->bi_sector = preq.sector_number;
707 preq.sector_number += seg[i].nsec;
710 /* This will be hit if the operation was a flush or discard. */
712 BUG_ON(operation != WRITE_FLUSH);
714 bio = bio_alloc(GFP_KERNEL, 0);
715 if (unlikely(bio == NULL))
718 biolist[nbio++] = bio;
719 bio->bi_bdev = preq.bdev;
720 bio->bi_private = pending_req;
721 bio->bi_end_io = end_block_io_op;
725 * We set it one so that the last submit_bio does not have to call
728 atomic_set(&pending_req->pendcnt, nbio);
730 /* Get a reference count for the disk queue and start sending I/O */
731 blk_start_plug(&plug);
733 for (i = 0; i < nbio; i++)
734 submit_bio(operation, biolist[i]);
736 /* Let the I/Os go.. */
737 blk_finish_plug(&plug);
739 if (operation == READ)
740 blkif->st_rd_sect += preq.nr_sects;
741 else if (operation & WRITE)
742 blkif->st_wr_sect += preq.nr_sects;
747 xen_blkbk_unmap(pending_req);
749 /* Haven't submitted any bio's yet. */
750 make_response(blkif, req->u.rw.id, req->operation, BLKIF_RSP_ERROR);
751 free_req(pending_req);
752 msleep(1); /* back off a bit */
756 for (i = 0; i < nbio; i++)
758 __end_block_io_op(pending_req, -EINVAL);
759 msleep(1); /* back off a bit */
766 * Put a response on the ring on how the operation fared.
768 static void make_response(struct xen_blkif *blkif, u64 id,
769 unsigned short op, int st)
771 struct blkif_response resp;
773 union blkif_back_rings *blk_rings = &blkif->blk_rings;
780 spin_lock_irqsave(&blkif->blk_ring_lock, flags);
781 /* Place on the response ring for the relevant domain. */
782 switch (blkif->blk_protocol) {
783 case BLKIF_PROTOCOL_NATIVE:
784 memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt),
785 &resp, sizeof(resp));
787 case BLKIF_PROTOCOL_X86_32:
788 memcpy(RING_GET_RESPONSE(&blk_rings->x86_32, blk_rings->x86_32.rsp_prod_pvt),
789 &resp, sizeof(resp));
791 case BLKIF_PROTOCOL_X86_64:
792 memcpy(RING_GET_RESPONSE(&blk_rings->x86_64, blk_rings->x86_64.rsp_prod_pvt),
793 &resp, sizeof(resp));
798 blk_rings->common.rsp_prod_pvt++;
799 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
800 spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
802 notify_remote_via_irq(blkif->irq);
805 static int __init xen_blkif_init(void)
813 blkbk = kzalloc(sizeof(struct xen_blkbk), GFP_KERNEL);
815 pr_alert(DRV_PFX "%s: out of memory!\n", __func__);
819 mmap_pages = xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST;
821 blkbk->pending_reqs = kzalloc(sizeof(blkbk->pending_reqs[0]) *
822 xen_blkif_reqs, GFP_KERNEL);
823 blkbk->pending_grant_handles = kmalloc(sizeof(blkbk->pending_grant_handles[0]) *
824 mmap_pages, GFP_KERNEL);
825 blkbk->pending_pages = kzalloc(sizeof(blkbk->pending_pages[0]) *
826 mmap_pages, GFP_KERNEL);
828 if (!blkbk->pending_reqs || !blkbk->pending_grant_handles ||
829 !blkbk->pending_pages) {
834 for (i = 0; i < mmap_pages; i++) {
835 blkbk->pending_grant_handles[i] = BLKBACK_INVALID_HANDLE;
836 blkbk->pending_pages[i] = alloc_page(GFP_KERNEL);
837 if (blkbk->pending_pages[i] == NULL) {
842 rc = xen_blkif_interface_init();
846 INIT_LIST_HEAD(&blkbk->pending_free);
847 spin_lock_init(&blkbk->pending_free_lock);
848 init_waitqueue_head(&blkbk->pending_free_wq);
850 for (i = 0; i < xen_blkif_reqs; i++)
851 list_add_tail(&blkbk->pending_reqs[i].free_list,
852 &blkbk->pending_free);
854 rc = xen_blkif_xenbus_init();
861 pr_alert(DRV_PFX "%s: out of memory\n", __func__);
863 kfree(blkbk->pending_reqs);
864 kfree(blkbk->pending_grant_handles);
865 if (blkbk->pending_pages) {
866 for (i = 0; i < mmap_pages; i++) {
867 if (blkbk->pending_pages[i])
868 __free_page(blkbk->pending_pages[i]);
870 kfree(blkbk->pending_pages);
877 module_init(xen_blkif_init);
879 MODULE_LICENSE("Dual BSD/GPL");
880 MODULE_ALIAS("xen-backend:vbd");