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>
45 #include <asm/xen/hypervisor.h>
46 #include <asm/xen/hypercall.h>
50 * These are rather arbitrary. They are fairly large because adjacent requests
51 * pulled from a communication ring are quite likely to end up being part of
52 * the same scatter/gather request at the disc.
54 * ** TRY INCREASING 'xen_blkif_reqs' IF WRITE SPEEDS SEEM TOO LOW **
56 * This will increase the chances of being able to write whole tracks.
57 * 64 should be enough to keep us competitive with Linux.
59 static int xen_blkif_reqs = 64;
60 module_param_named(reqs, xen_blkif_reqs, int, 0);
61 MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate");
63 /* Run-time switchable: /sys/module/blkback/parameters/ */
64 static unsigned int log_stats;
65 module_param(log_stats, int, 0644);
68 * Each outstanding request that we've passed to the lower device layers has a
69 * 'pending_req' allocated to it. Each buffer_head that completes decrements
70 * the pendcnt towards zero. When it hits zero, the specified domain has a
71 * response queued for it, with the saved 'id' passed back.
74 struct xen_blkif *blkif;
78 unsigned short operation;
80 struct list_head free_list;
83 #define BLKBACK_INVALID_HANDLE (~0)
86 struct pending_req *pending_reqs;
87 /* List of all 'pending_req' available */
88 struct list_head pending_free;
89 /* And its spinlock. */
90 spinlock_t pending_free_lock;
91 wait_queue_head_t pending_free_wq;
92 /* The list of all pages that are available. */
93 struct page **pending_pages;
94 /* And the grant handles that are available. */
95 grant_handle_t *pending_grant_handles;
98 static struct xen_blkbk *blkbk;
101 * Little helpful macro to figure out the index and virtual address of the
102 * pending_pages[..]. For each 'pending_req' we have have up to
103 * BLKIF_MAX_SEGMENTS_PER_REQUEST (11) pages. The seg would be from 0 through
104 * 10 and would index in the pending_pages[..].
106 static inline int vaddr_pagenr(struct pending_req *req, int seg)
108 return (req - blkbk->pending_reqs) *
109 BLKIF_MAX_SEGMENTS_PER_REQUEST + seg;
112 #define pending_page(req, seg) pending_pages[vaddr_pagenr(req, seg)]
114 static inline unsigned long vaddr(struct pending_req *req, int seg)
116 unsigned long pfn = page_to_pfn(blkbk->pending_page(req, seg));
117 return (unsigned long)pfn_to_kaddr(pfn);
120 #define pending_handle(_req, _seg) \
121 (blkbk->pending_grant_handles[vaddr_pagenr(_req, _seg)])
124 static int do_block_io_op(struct xen_blkif *blkif);
125 static int dispatch_rw_block_io(struct xen_blkif *blkif,
126 struct blkif_request *req,
127 struct pending_req *pending_req);
128 static void make_response(struct xen_blkif *blkif, u64 id,
129 unsigned short op, int st);
132 * Retrieve from the 'pending_reqs' a free pending_req structure to be used.
134 static struct pending_req *alloc_req(void)
136 struct pending_req *req = NULL;
139 spin_lock_irqsave(&blkbk->pending_free_lock, flags);
140 if (!list_empty(&blkbk->pending_free)) {
141 req = list_entry(blkbk->pending_free.next, struct pending_req,
143 list_del(&req->free_list);
145 spin_unlock_irqrestore(&blkbk->pending_free_lock, flags);
150 * Return the 'pending_req' structure back to the freepool. We also
151 * wake up the thread if it was waiting for a free page.
153 static void free_req(struct pending_req *req)
158 spin_lock_irqsave(&blkbk->pending_free_lock, flags);
159 was_empty = list_empty(&blkbk->pending_free);
160 list_add(&req->free_list, &blkbk->pending_free);
161 spin_unlock_irqrestore(&blkbk->pending_free_lock, flags);
163 wake_up(&blkbk->pending_free_wq);
167 * Routines for managing virtual block devices (vbds).
169 static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif,
172 struct xen_vbd *vbd = &blkif->vbd;
175 if ((operation != READ) && vbd->readonly)
178 if (likely(req->nr_sects)) {
179 blkif_sector_t end = req->sector_number + req->nr_sects;
181 if (unlikely(end < req->sector_number))
183 if (unlikely(end > vbd_sz(vbd)))
187 req->dev = vbd->pdevice;
188 req->bdev = vbd->bdev;
195 static void xen_vbd_resize(struct xen_blkif *blkif)
197 struct xen_vbd *vbd = &blkif->vbd;
198 struct xenbus_transaction xbt;
200 struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be);
201 unsigned long long new_size = vbd_sz(vbd);
203 pr_info(DRV_PFX "VBD Resize: Domid: %d, Device: (%d, %d)\n",
204 blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
205 pr_info(DRV_PFX "VBD Resize: new size %llu\n", new_size);
206 vbd->size = new_size;
208 err = xenbus_transaction_start(&xbt);
210 pr_warn(DRV_PFX "Error starting transaction");
213 err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
214 (unsigned long long)vbd_sz(vbd));
216 pr_warn(DRV_PFX "Error writing new size");
220 * Write the current state; we will use this to synchronize
221 * the front-end. If the current state is "connected" the
222 * front-end will get the new size information online.
224 err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
226 pr_warn(DRV_PFX "Error writing the state");
230 err = xenbus_transaction_end(xbt, 0);
234 pr_warn(DRV_PFX "Error ending transaction");
237 xenbus_transaction_end(xbt, 1);
241 * Notification from the guest OS.
243 static void blkif_notify_work(struct xen_blkif *blkif)
245 blkif->waiting_reqs = 1;
249 irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
251 blkif_notify_work(dev_id);
256 * SCHEDULER FUNCTIONS
259 static void print_stats(struct xen_blkif *blkif)
261 pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d"
263 current->comm, blkif->st_oo_req,
264 blkif->st_rd_req, blkif->st_wr_req,
265 blkif->st_f_req, blkif->st_ds_req);
266 blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000);
267 blkif->st_rd_req = 0;
268 blkif->st_wr_req = 0;
269 blkif->st_oo_req = 0;
270 blkif->st_ds_req = 0;
273 int xen_blkif_schedule(void *arg)
275 struct xen_blkif *blkif = arg;
276 struct xen_vbd *vbd = &blkif->vbd;
278 xen_blkif_get(blkif);
280 while (!kthread_should_stop()) {
283 if (unlikely(vbd->size != vbd_sz(vbd)))
284 xen_vbd_resize(blkif);
286 wait_event_interruptible(
288 blkif->waiting_reqs || kthread_should_stop());
289 wait_event_interruptible(
290 blkbk->pending_free_wq,
291 !list_empty(&blkbk->pending_free) ||
292 kthread_should_stop());
294 blkif->waiting_reqs = 0;
295 smp_mb(); /* clear flag *before* checking for work */
297 if (do_block_io_op(blkif))
298 blkif->waiting_reqs = 1;
300 if (log_stats && time_after(jiffies, blkif->st_print))
307 blkif->xenblkd = NULL;
308 xen_blkif_put(blkif);
318 * Unmap the grant references, and also remove the M2P over-rides
319 * used in the 'pending_req'.
321 static void xen_blkbk_unmap(struct pending_req *req)
323 struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
324 unsigned int i, invcount = 0;
325 grant_handle_t handle;
328 for (i = 0; i < req->nr_pages; i++) {
329 handle = pending_handle(req, i);
330 if (handle == BLKBACK_INVALID_HANDLE)
332 gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
333 GNTMAP_host_map, handle);
334 pending_handle(req, i) = BLKBACK_INVALID_HANDLE;
338 ret = HYPERVISOR_grant_table_op(
339 GNTTABOP_unmap_grant_ref, unmap, invcount);
342 * Note, we use invcount, so nr->pages, so we can't index
343 * using vaddr(req, i).
345 for (i = 0; i < invcount; i++) {
346 ret = m2p_remove_override(
347 virt_to_page(unmap[i].host_addr), false);
349 pr_alert(DRV_PFX "Failed to remove M2P override for %lx\n",
350 (unsigned long)unmap[i].host_addr);
356 static int xen_blkbk_map(struct blkif_request *req,
357 struct pending_req *pending_req,
358 struct seg_buf seg[])
360 struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
362 int nseg = req->u.rw.nr_segments;
366 * Fill out preq.nr_sects with proper amount of sectors, and setup
367 * assign map[..] with the PFN of the page in our domain with the
368 * corresponding grant reference for each page.
370 for (i = 0; i < nseg; i++) {
373 flags = GNTMAP_host_map;
374 if (pending_req->operation != BLKIF_OP_READ)
375 flags |= GNTMAP_readonly;
376 gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
377 req->u.rw.seg[i].gref,
378 pending_req->blkif->domid);
381 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
385 * Now swizzle the MFN in our domain with the MFN from the other domain
386 * so that when we access vaddr(pending_req,i) it has the contents of
387 * the page from the other domain.
389 for (i = 0; i < nseg; i++) {
390 if (unlikely(map[i].status != 0)) {
391 pr_debug(DRV_PFX "invalid buffer -- could not remap it\n");
392 map[i].handle = BLKBACK_INVALID_HANDLE;
396 pending_handle(pending_req, i) = map[i].handle;
401 ret = m2p_add_override(PFN_DOWN(map[i].dev_bus_addr),
402 blkbk->pending_page(pending_req, i), NULL);
404 pr_alert(DRV_PFX "Failed to install M2P override for %lx (ret: %d)\n",
405 (unsigned long)map[i].dev_bus_addr, ret);
406 /* We could switch over to GNTTABOP_copy */
410 seg[i].buf = map[i].dev_bus_addr |
411 (req->u.rw.seg[i].first_sect << 9);
416 static int dispatch_discard_io(struct xen_blkif *blkif,
417 struct blkif_request *req)
420 int status = BLKIF_RSP_OKAY;
421 struct block_device *bdev = blkif->vbd.bdev;
425 xen_blkif_get(blkif);
426 if (blkif->blk_backend_type == BLKIF_BACKEND_PHY ||
427 blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
428 unsigned long secure = (blkif->vbd.discard_secure &&
429 (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
430 BLKDEV_DISCARD_SECURE : 0;
431 err = blkdev_issue_discard(bdev,
432 req->u.discard.sector_number,
433 req->u.discard.nr_sectors,
438 if (err == -EOPNOTSUPP) {
439 pr_debug(DRV_PFX "discard op failed, not supported\n");
440 status = BLKIF_RSP_EOPNOTSUPP;
442 status = BLKIF_RSP_ERROR;
444 make_response(blkif, req->u.discard.id, req->operation, status);
445 xen_blkif_put(blkif);
449 static void xen_blk_drain_io(struct xen_blkif *blkif)
451 atomic_set(&blkif->drain, 1);
453 /* The initial value is one, and one refcnt taken at the
454 * start of the xen_blkif_schedule thread. */
455 if (atomic_read(&blkif->refcnt) <= 2)
457 wait_for_completion_interruptible_timeout(
458 &blkif->drain_complete, HZ);
460 if (!atomic_read(&blkif->drain))
462 } while (!kthread_should_stop());
463 atomic_set(&blkif->drain, 0);
467 * Completion callback on the bio's. Called as bh->b_end_io()
470 static void __end_block_io_op(struct pending_req *pending_req, int error)
472 /* An error fails the entire request. */
473 if ((pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE) &&
474 (error == -EOPNOTSUPP)) {
475 pr_debug(DRV_PFX "flush diskcache op failed, not supported\n");
476 xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0);
477 pending_req->status = BLKIF_RSP_EOPNOTSUPP;
478 } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
479 (error == -EOPNOTSUPP)) {
480 pr_debug(DRV_PFX "write barrier op failed, not supported\n");
481 xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0);
482 pending_req->status = BLKIF_RSP_EOPNOTSUPP;
484 pr_debug(DRV_PFX "Buffer not up-to-date at end of operation,"
485 " error=%d\n", error);
486 pending_req->status = BLKIF_RSP_ERROR;
490 * If all of the bio's have completed it is time to unmap
491 * the grant references associated with 'request' and provide
492 * the proper response on the ring.
494 if (atomic_dec_and_test(&pending_req->pendcnt)) {
495 xen_blkbk_unmap(pending_req);
496 make_response(pending_req->blkif, pending_req->id,
497 pending_req->operation, pending_req->status);
498 xen_blkif_put(pending_req->blkif);
499 if (atomic_read(&pending_req->blkif->refcnt) <= 2) {
500 if (atomic_read(&pending_req->blkif->drain))
501 complete(&pending_req->blkif->drain_complete);
503 free_req(pending_req);
510 static void end_block_io_op(struct bio *bio, int error)
512 __end_block_io_op(bio->bi_private, error);
519 * Function to copy the from the ring buffer the 'struct blkif_request'
520 * (which has the sectors we want, number of them, grant references, etc),
521 * and transmute it to the block API to hand it over to the proper block disk.
524 __do_block_io_op(struct xen_blkif *blkif)
526 union blkif_back_rings *blk_rings = &blkif->blk_rings;
527 struct blkif_request req;
528 struct pending_req *pending_req;
532 rc = blk_rings->common.req_cons;
533 rp = blk_rings->common.sring->req_prod;
534 rmb(); /* Ensure we see queued requests up to 'rp'. */
538 if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
541 if (kthread_should_stop()) {
546 pending_req = alloc_req();
547 if (NULL == pending_req) {
553 switch (blkif->blk_protocol) {
554 case BLKIF_PROTOCOL_NATIVE:
555 memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req));
557 case BLKIF_PROTOCOL_X86_32:
558 blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc));
560 case BLKIF_PROTOCOL_X86_64:
561 blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc));
566 blk_rings->common.req_cons = ++rc; /* before make_response() */
568 /* Apply all sanity checks to /private copy/ of request. */
570 if (unlikely(req.operation == BLKIF_OP_DISCARD)) {
571 free_req(pending_req);
572 if (dispatch_discard_io(blkif, &req))
574 } else if (dispatch_rw_block_io(blkif, &req, pending_req))
577 /* Yield point for this unbounded loop. */
585 do_block_io_op(struct xen_blkif *blkif)
587 union blkif_back_rings *blk_rings = &blkif->blk_rings;
591 more_to_do = __do_block_io_op(blkif);
595 RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
596 } while (more_to_do);
601 * Transmutation of the 'struct blkif_request' to a proper 'struct bio'
602 * and call the 'submit_bio' to pass it to the underlying storage.
604 static int dispatch_rw_block_io(struct xen_blkif *blkif,
605 struct blkif_request *req,
606 struct pending_req *pending_req)
608 struct phys_req preq;
609 struct seg_buf seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
611 struct bio *bio = NULL;
612 struct bio *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST];
615 struct blk_plug plug;
618 switch (req->operation) {
625 operation = WRITE_ODIRECT;
627 case BLKIF_OP_WRITE_BARRIER:
629 case BLKIF_OP_FLUSH_DISKCACHE:
631 operation = WRITE_FLUSH;
634 operation = 0; /* make gcc happy */
639 /* Check that the number of segments is sane. */
640 nseg = req->u.rw.nr_segments;
642 if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
643 unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
644 pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
646 /* Haven't submitted any bio's yet. */
650 preq.dev = req->u.rw.handle;
651 preq.sector_number = req->u.rw.sector_number;
654 pending_req->blkif = blkif;
655 pending_req->id = req->u.rw.id;
656 pending_req->operation = req->operation;
657 pending_req->status = BLKIF_RSP_OKAY;
658 pending_req->nr_pages = nseg;
660 for (i = 0; i < nseg; i++) {
661 seg[i].nsec = req->u.rw.seg[i].last_sect -
662 req->u.rw.seg[i].first_sect + 1;
663 if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
664 (req->u.rw.seg[i].last_sect < req->u.rw.seg[i].first_sect))
666 preq.nr_sects += seg[i].nsec;
670 if (xen_vbd_translate(&preq, blkif, operation) != 0) {
671 pr_debug(DRV_PFX "access denied: %s of [%llu,%llu] on dev=%04x\n",
672 operation == READ ? "read" : "write",
674 preq.sector_number + preq.nr_sects, preq.dev);
679 * This check _MUST_ be done after xen_vbd_translate as the preq.bdev
682 for (i = 0; i < nseg; i++) {
683 if (((int)preq.sector_number|(int)seg[i].nsec) &
684 ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
685 pr_debug(DRV_PFX "Misaligned I/O request from domain %d",
691 /* Wait on all outstanding I/O's and once that has been completed
692 * issue the WRITE_FLUSH.
695 xen_blk_drain_io(pending_req->blkif);
698 * If we have failed at this point, we need to undo the M2P override,
699 * set gnttab_set_unmap_op on all of the grant references and perform
700 * the hypercall to unmap the grants - that is all done in
703 if (xen_blkbk_map(req, pending_req, seg))
707 * This corresponding xen_blkif_put is done in __end_block_io_op, or
708 * below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
710 xen_blkif_get(blkif);
712 for (i = 0; i < nseg; i++) {
713 while ((bio == NULL) ||
715 blkbk->pending_page(pending_req, i),
717 seg[i].buf & ~PAGE_MASK) == 0)) {
719 bio = bio_alloc(GFP_KERNEL, nseg-i);
720 if (unlikely(bio == NULL))
723 biolist[nbio++] = bio;
724 bio->bi_bdev = preq.bdev;
725 bio->bi_private = pending_req;
726 bio->bi_end_io = end_block_io_op;
727 bio->bi_sector = preq.sector_number;
730 preq.sector_number += seg[i].nsec;
733 /* This will be hit if the operation was a flush or discard. */
735 BUG_ON(operation != WRITE_FLUSH);
737 bio = bio_alloc(GFP_KERNEL, 0);
738 if (unlikely(bio == NULL))
741 biolist[nbio++] = bio;
742 bio->bi_bdev = preq.bdev;
743 bio->bi_private = pending_req;
744 bio->bi_end_io = end_block_io_op;
748 * We set it one so that the last submit_bio does not have to call
751 atomic_set(&pending_req->pendcnt, nbio);
753 /* Get a reference count for the disk queue and start sending I/O */
754 blk_start_plug(&plug);
756 for (i = 0; i < nbio; i++)
757 submit_bio(operation, biolist[i]);
759 /* Let the I/Os go.. */
760 blk_finish_plug(&plug);
762 if (operation == READ)
763 blkif->st_rd_sect += preq.nr_sects;
764 else if (operation & WRITE)
765 blkif->st_wr_sect += preq.nr_sects;
770 xen_blkbk_unmap(pending_req);
772 /* Haven't submitted any bio's yet. */
773 make_response(blkif, req->u.rw.id, req->operation, BLKIF_RSP_ERROR);
774 free_req(pending_req);
775 msleep(1); /* back off a bit */
779 for (i = 0; i < nbio; i++)
781 __end_block_io_op(pending_req, -EINVAL);
782 msleep(1); /* back off a bit */
789 * Put a response on the ring on how the operation fared.
791 static void make_response(struct xen_blkif *blkif, u64 id,
792 unsigned short op, int st)
794 struct blkif_response resp;
796 union blkif_back_rings *blk_rings = &blkif->blk_rings;
803 spin_lock_irqsave(&blkif->blk_ring_lock, flags);
804 /* Place on the response ring for the relevant domain. */
805 switch (blkif->blk_protocol) {
806 case BLKIF_PROTOCOL_NATIVE:
807 memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt),
808 &resp, sizeof(resp));
810 case BLKIF_PROTOCOL_X86_32:
811 memcpy(RING_GET_RESPONSE(&blk_rings->x86_32, blk_rings->x86_32.rsp_prod_pvt),
812 &resp, sizeof(resp));
814 case BLKIF_PROTOCOL_X86_64:
815 memcpy(RING_GET_RESPONSE(&blk_rings->x86_64, blk_rings->x86_64.rsp_prod_pvt),
816 &resp, sizeof(resp));
821 blk_rings->common.rsp_prod_pvt++;
822 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
823 spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
825 notify_remote_via_irq(blkif->irq);
828 static int __init xen_blkif_init(void)
833 if (!xen_pv_domain())
836 blkbk = kzalloc(sizeof(struct xen_blkbk), GFP_KERNEL);
838 pr_alert(DRV_PFX "%s: out of memory!\n", __func__);
842 mmap_pages = xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST;
844 blkbk->pending_reqs = kzalloc(sizeof(blkbk->pending_reqs[0]) *
845 xen_blkif_reqs, GFP_KERNEL);
846 blkbk->pending_grant_handles = kmalloc(sizeof(blkbk->pending_grant_handles[0]) *
847 mmap_pages, GFP_KERNEL);
848 blkbk->pending_pages = kzalloc(sizeof(blkbk->pending_pages[0]) *
849 mmap_pages, GFP_KERNEL);
851 if (!blkbk->pending_reqs || !blkbk->pending_grant_handles ||
852 !blkbk->pending_pages) {
857 for (i = 0; i < mmap_pages; i++) {
858 blkbk->pending_grant_handles[i] = BLKBACK_INVALID_HANDLE;
859 blkbk->pending_pages[i] = alloc_page(GFP_KERNEL);
860 if (blkbk->pending_pages[i] == NULL) {
865 rc = xen_blkif_interface_init();
869 INIT_LIST_HEAD(&blkbk->pending_free);
870 spin_lock_init(&blkbk->pending_free_lock);
871 init_waitqueue_head(&blkbk->pending_free_wq);
873 for (i = 0; i < xen_blkif_reqs; i++)
874 list_add_tail(&blkbk->pending_reqs[i].free_list,
875 &blkbk->pending_free);
877 rc = xen_blkif_xenbus_init();
884 pr_alert(DRV_PFX "%s: out of memory\n", __func__);
886 kfree(blkbk->pending_reqs);
887 kfree(blkbk->pending_grant_handles);
888 if (blkbk->pending_pages) {
889 for (i = 0; i < mmap_pages; i++) {
890 if (blkbk->pending_pages[i])
891 __free_page(blkbk->pending_pages[i]);
893 kfree(blkbk->pending_pages);
900 module_init(xen_blkif_init);
902 MODULE_LICENSE("Dual BSD/GPL");
903 MODULE_ALIAS("xen-backend:vbd");