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 struct page
*pages
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
325 unsigned int i
, invcount
= 0;
326 grant_handle_t handle
;
329 for (i
= 0; i
< req
->nr_pages
; i
++) {
330 handle
= pending_handle(req
, i
);
331 if (handle
== BLKBACK_INVALID_HANDLE
)
333 gnttab_set_unmap_op(&unmap
[invcount
], vaddr(req
, i
),
334 GNTMAP_host_map
, handle
);
335 pending_handle(req
, i
) = BLKBACK_INVALID_HANDLE
;
336 pages
[invcount
] = virt_to_page(vaddr(req
, i
));
340 ret
= gnttab_unmap_refs(unmap
, pages
, invcount
, false);
344 static int xen_blkbk_map(struct blkif_request
*req
,
345 struct pending_req
*pending_req
,
346 struct seg_buf seg
[])
348 struct gnttab_map_grant_ref map
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
350 int nseg
= req
->u
.rw
.nr_segments
;
354 * Fill out preq.nr_sects with proper amount of sectors, and setup
355 * assign map[..] with the PFN of the page in our domain with the
356 * corresponding grant reference for each page.
358 for (i
= 0; i
< nseg
; i
++) {
361 flags
= GNTMAP_host_map
;
362 if (pending_req
->operation
!= BLKIF_OP_READ
)
363 flags
|= GNTMAP_readonly
;
364 gnttab_set_map_op(&map
[i
], vaddr(pending_req
, i
), flags
,
365 req
->u
.rw
.seg
[i
].gref
,
366 pending_req
->blkif
->domid
);
369 ret
= gnttab_map_refs(map
, NULL
, &blkbk
->pending_page(pending_req
, 0), nseg
);
373 * Now swizzle the MFN in our domain with the MFN from the other domain
374 * so that when we access vaddr(pending_req,i) it has the contents of
375 * the page from the other domain.
377 for (i
= 0; i
< nseg
; i
++) {
378 if (unlikely(map
[i
].status
!= 0)) {
379 pr_debug(DRV_PFX
"invalid buffer -- could not remap it\n");
380 map
[i
].handle
= BLKBACK_INVALID_HANDLE
;
384 pending_handle(pending_req
, i
) = map
[i
].handle
;
389 seg
[i
].buf
= map
[i
].dev_bus_addr
|
390 (req
->u
.rw
.seg
[i
].first_sect
<< 9);
395 static int dispatch_discard_io(struct xen_blkif
*blkif
,
396 struct blkif_request
*req
)
399 int status
= BLKIF_RSP_OKAY
;
400 struct block_device
*bdev
= blkif
->vbd
.bdev
;
401 unsigned long secure
;
405 xen_blkif_get(blkif
);
406 secure
= (blkif
->vbd
.discard_secure
&&
407 (req
->u
.discard
.flag
& BLKIF_DISCARD_SECURE
)) ?
408 BLKDEV_DISCARD_SECURE
: 0;
410 err
= blkdev_issue_discard(bdev
, req
->u
.discard
.sector_number
,
411 req
->u
.discard
.nr_sectors
,
414 if (err
== -EOPNOTSUPP
) {
415 pr_debug(DRV_PFX
"discard op failed, not supported\n");
416 status
= BLKIF_RSP_EOPNOTSUPP
;
418 status
= BLKIF_RSP_ERROR
;
420 make_response(blkif
, req
->u
.discard
.id
, req
->operation
, status
);
421 xen_blkif_put(blkif
);
425 static void xen_blk_drain_io(struct xen_blkif
*blkif
)
427 atomic_set(&blkif
->drain
, 1);
429 /* The initial value is one, and one refcnt taken at the
430 * start of the xen_blkif_schedule thread. */
431 if (atomic_read(&blkif
->refcnt
) <= 2)
433 wait_for_completion_interruptible_timeout(
434 &blkif
->drain_complete
, HZ
);
436 if (!atomic_read(&blkif
->drain
))
438 } while (!kthread_should_stop());
439 atomic_set(&blkif
->drain
, 0);
443 * Completion callback on the bio's. Called as bh->b_end_io()
446 static void __end_block_io_op(struct pending_req
*pending_req
, int error
)
448 /* An error fails the entire request. */
449 if ((pending_req
->operation
== BLKIF_OP_FLUSH_DISKCACHE
) &&
450 (error
== -EOPNOTSUPP
)) {
451 pr_debug(DRV_PFX
"flush diskcache op failed, not supported\n");
452 xen_blkbk_flush_diskcache(XBT_NIL
, pending_req
->blkif
->be
, 0);
453 pending_req
->status
= BLKIF_RSP_EOPNOTSUPP
;
454 } else if ((pending_req
->operation
== BLKIF_OP_WRITE_BARRIER
) &&
455 (error
== -EOPNOTSUPP
)) {
456 pr_debug(DRV_PFX
"write barrier op failed, not supported\n");
457 xen_blkbk_barrier(XBT_NIL
, pending_req
->blkif
->be
, 0);
458 pending_req
->status
= BLKIF_RSP_EOPNOTSUPP
;
460 pr_debug(DRV_PFX
"Buffer not up-to-date at end of operation,"
461 " error=%d\n", error
);
462 pending_req
->status
= BLKIF_RSP_ERROR
;
466 * If all of the bio's have completed it is time to unmap
467 * the grant references associated with 'request' and provide
468 * the proper response on the ring.
470 if (atomic_dec_and_test(&pending_req
->pendcnt
)) {
471 xen_blkbk_unmap(pending_req
);
472 make_response(pending_req
->blkif
, pending_req
->id
,
473 pending_req
->operation
, pending_req
->status
);
474 xen_blkif_put(pending_req
->blkif
);
475 if (atomic_read(&pending_req
->blkif
->refcnt
) <= 2) {
476 if (atomic_read(&pending_req
->blkif
->drain
))
477 complete(&pending_req
->blkif
->drain_complete
);
479 free_req(pending_req
);
486 static void end_block_io_op(struct bio
*bio
, int error
)
488 __end_block_io_op(bio
->bi_private
, error
);
495 * Function to copy the from the ring buffer the 'struct blkif_request'
496 * (which has the sectors we want, number of them, grant references, etc),
497 * and transmute it to the block API to hand it over to the proper block disk.
500 __do_block_io_op(struct xen_blkif
*blkif
)
502 union blkif_back_rings
*blk_rings
= &blkif
->blk_rings
;
503 struct blkif_request req
;
504 struct pending_req
*pending_req
;
508 rc
= blk_rings
->common
.req_cons
;
509 rp
= blk_rings
->common
.sring
->req_prod
;
510 rmb(); /* Ensure we see queued requests up to 'rp'. */
514 if (RING_REQUEST_CONS_OVERFLOW(&blk_rings
->common
, rc
))
517 if (kthread_should_stop()) {
522 pending_req
= alloc_req();
523 if (NULL
== pending_req
) {
529 switch (blkif
->blk_protocol
) {
530 case BLKIF_PROTOCOL_NATIVE
:
531 memcpy(&req
, RING_GET_REQUEST(&blk_rings
->native
, rc
), sizeof(req
));
533 case BLKIF_PROTOCOL_X86_32
:
534 blkif_get_x86_32_req(&req
, RING_GET_REQUEST(&blk_rings
->x86_32
, rc
));
536 case BLKIF_PROTOCOL_X86_64
:
537 blkif_get_x86_64_req(&req
, RING_GET_REQUEST(&blk_rings
->x86_64
, rc
));
542 blk_rings
->common
.req_cons
= ++rc
; /* before make_response() */
544 /* Apply all sanity checks to /private copy/ of request. */
546 if (unlikely(req
.operation
== BLKIF_OP_DISCARD
)) {
547 free_req(pending_req
);
548 if (dispatch_discard_io(blkif
, &req
))
550 } else if (dispatch_rw_block_io(blkif
, &req
, pending_req
))
553 /* Yield point for this unbounded loop. */
561 do_block_io_op(struct xen_blkif
*blkif
)
563 union blkif_back_rings
*blk_rings
= &blkif
->blk_rings
;
567 more_to_do
= __do_block_io_op(blkif
);
571 RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings
->common
, more_to_do
);
572 } while (more_to_do
);
577 * Transmutation of the 'struct blkif_request' to a proper 'struct bio'
578 * and call the 'submit_bio' to pass it to the underlying storage.
580 static int dispatch_rw_block_io(struct xen_blkif
*blkif
,
581 struct blkif_request
*req
,
582 struct pending_req
*pending_req
)
584 struct phys_req preq
;
585 struct seg_buf seg
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
587 struct bio
*bio
= NULL
;
588 struct bio
*biolist
[BLKIF_MAX_SEGMENTS_PER_REQUEST
];
591 struct blk_plug plug
;
594 switch (req
->operation
) {
601 operation
= WRITE_ODIRECT
;
603 case BLKIF_OP_WRITE_BARRIER
:
605 case BLKIF_OP_FLUSH_DISKCACHE
:
607 operation
= WRITE_FLUSH
;
610 operation
= 0; /* make gcc happy */
615 /* Check that the number of segments is sane. */
616 nseg
= req
->u
.rw
.nr_segments
;
618 if (unlikely(nseg
== 0 && operation
!= WRITE_FLUSH
) ||
619 unlikely(nseg
> BLKIF_MAX_SEGMENTS_PER_REQUEST
)) {
620 pr_debug(DRV_PFX
"Bad number of segments in request (%d)\n",
622 /* Haven't submitted any bio's yet. */
626 preq
.dev
= req
->u
.rw
.handle
;
627 preq
.sector_number
= req
->u
.rw
.sector_number
;
630 pending_req
->blkif
= blkif
;
631 pending_req
->id
= req
->u
.rw
.id
;
632 pending_req
->operation
= req
->operation
;
633 pending_req
->status
= BLKIF_RSP_OKAY
;
634 pending_req
->nr_pages
= nseg
;
636 for (i
= 0; i
< nseg
; i
++) {
637 seg
[i
].nsec
= req
->u
.rw
.seg
[i
].last_sect
-
638 req
->u
.rw
.seg
[i
].first_sect
+ 1;
639 if ((req
->u
.rw
.seg
[i
].last_sect
>= (PAGE_SIZE
>> 9)) ||
640 (req
->u
.rw
.seg
[i
].last_sect
< req
->u
.rw
.seg
[i
].first_sect
))
642 preq
.nr_sects
+= seg
[i
].nsec
;
646 if (xen_vbd_translate(&preq
, blkif
, operation
) != 0) {
647 pr_debug(DRV_PFX
"access denied: %s of [%llu,%llu] on dev=%04x\n",
648 operation
== READ
? "read" : "write",
650 preq
.sector_number
+ preq
.nr_sects
, preq
.dev
);
655 * This check _MUST_ be done after xen_vbd_translate as the preq.bdev
658 for (i
= 0; i
< nseg
; i
++) {
659 if (((int)preq
.sector_number
|(int)seg
[i
].nsec
) &
660 ((bdev_logical_block_size(preq
.bdev
) >> 9) - 1)) {
661 pr_debug(DRV_PFX
"Misaligned I/O request from domain %d",
667 /* Wait on all outstanding I/O's and once that has been completed
668 * issue the WRITE_FLUSH.
671 xen_blk_drain_io(pending_req
->blkif
);
674 * If we have failed at this point, we need to undo the M2P override,
675 * set gnttab_set_unmap_op on all of the grant references and perform
676 * the hypercall to unmap the grants - that is all done in
679 if (xen_blkbk_map(req
, pending_req
, seg
))
683 * This corresponding xen_blkif_put is done in __end_block_io_op, or
684 * below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
686 xen_blkif_get(blkif
);
688 for (i
= 0; i
< nseg
; i
++) {
689 while ((bio
== NULL
) ||
691 blkbk
->pending_page(pending_req
, i
),
693 seg
[i
].buf
& ~PAGE_MASK
) == 0)) {
695 bio
= bio_alloc(GFP_KERNEL
, nseg
-i
);
696 if (unlikely(bio
== NULL
))
699 biolist
[nbio
++] = bio
;
700 bio
->bi_bdev
= preq
.bdev
;
701 bio
->bi_private
= pending_req
;
702 bio
->bi_end_io
= end_block_io_op
;
703 bio
->bi_sector
= preq
.sector_number
;
706 preq
.sector_number
+= seg
[i
].nsec
;
709 /* This will be hit if the operation was a flush or discard. */
711 BUG_ON(operation
!= WRITE_FLUSH
);
713 bio
= bio_alloc(GFP_KERNEL
, 0);
714 if (unlikely(bio
== NULL
))
717 biolist
[nbio
++] = bio
;
718 bio
->bi_bdev
= preq
.bdev
;
719 bio
->bi_private
= pending_req
;
720 bio
->bi_end_io
= end_block_io_op
;
724 * We set it one so that the last submit_bio does not have to call
727 atomic_set(&pending_req
->pendcnt
, nbio
);
729 /* Get a reference count for the disk queue and start sending I/O */
730 blk_start_plug(&plug
);
732 for (i
= 0; i
< nbio
; i
++)
733 submit_bio(operation
, biolist
[i
]);
735 /* Let the I/Os go.. */
736 blk_finish_plug(&plug
);
738 if (operation
== READ
)
739 blkif
->st_rd_sect
+= preq
.nr_sects
;
740 else if (operation
& WRITE
)
741 blkif
->st_wr_sect
+= preq
.nr_sects
;
746 xen_blkbk_unmap(pending_req
);
748 /* Haven't submitted any bio's yet. */
749 make_response(blkif
, req
->u
.rw
.id
, req
->operation
, BLKIF_RSP_ERROR
);
750 free_req(pending_req
);
751 msleep(1); /* back off a bit */
755 for (i
= 0; i
< nbio
; i
++)
757 __end_block_io_op(pending_req
, -EINVAL
);
758 msleep(1); /* back off a bit */
765 * Put a response on the ring on how the operation fared.
767 static void make_response(struct xen_blkif
*blkif
, u64 id
,
768 unsigned short op
, int st
)
770 struct blkif_response resp
;
772 union blkif_back_rings
*blk_rings
= &blkif
->blk_rings
;
779 spin_lock_irqsave(&blkif
->blk_ring_lock
, flags
);
780 /* Place on the response ring for the relevant domain. */
781 switch (blkif
->blk_protocol
) {
782 case BLKIF_PROTOCOL_NATIVE
:
783 memcpy(RING_GET_RESPONSE(&blk_rings
->native
, blk_rings
->native
.rsp_prod_pvt
),
784 &resp
, sizeof(resp
));
786 case BLKIF_PROTOCOL_X86_32
:
787 memcpy(RING_GET_RESPONSE(&blk_rings
->x86_32
, blk_rings
->x86_32
.rsp_prod_pvt
),
788 &resp
, sizeof(resp
));
790 case BLKIF_PROTOCOL_X86_64
:
791 memcpy(RING_GET_RESPONSE(&blk_rings
->x86_64
, blk_rings
->x86_64
.rsp_prod_pvt
),
792 &resp
, sizeof(resp
));
797 blk_rings
->common
.rsp_prod_pvt
++;
798 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings
->common
, notify
);
799 spin_unlock_irqrestore(&blkif
->blk_ring_lock
, flags
);
801 notify_remote_via_irq(blkif
->irq
);
804 static int __init
xen_blkif_init(void)
812 blkbk
= kzalloc(sizeof(struct xen_blkbk
), GFP_KERNEL
);
814 pr_alert(DRV_PFX
"%s: out of memory!\n", __func__
);
818 mmap_pages
= xen_blkif_reqs
* BLKIF_MAX_SEGMENTS_PER_REQUEST
;
820 blkbk
->pending_reqs
= kzalloc(sizeof(blkbk
->pending_reqs
[0]) *
821 xen_blkif_reqs
, GFP_KERNEL
);
822 blkbk
->pending_grant_handles
= kmalloc(sizeof(blkbk
->pending_grant_handles
[0]) *
823 mmap_pages
, GFP_KERNEL
);
824 blkbk
->pending_pages
= kzalloc(sizeof(blkbk
->pending_pages
[0]) *
825 mmap_pages
, GFP_KERNEL
);
827 if (!blkbk
->pending_reqs
|| !blkbk
->pending_grant_handles
||
828 !blkbk
->pending_pages
) {
833 for (i
= 0; i
< mmap_pages
; i
++) {
834 blkbk
->pending_grant_handles
[i
] = BLKBACK_INVALID_HANDLE
;
835 blkbk
->pending_pages
[i
] = alloc_page(GFP_KERNEL
);
836 if (blkbk
->pending_pages
[i
] == NULL
) {
841 rc
= xen_blkif_interface_init();
845 INIT_LIST_HEAD(&blkbk
->pending_free
);
846 spin_lock_init(&blkbk
->pending_free_lock
);
847 init_waitqueue_head(&blkbk
->pending_free_wq
);
849 for (i
= 0; i
< xen_blkif_reqs
; i
++)
850 list_add_tail(&blkbk
->pending_reqs
[i
].free_list
,
851 &blkbk
->pending_free
);
853 rc
= xen_blkif_xenbus_init();
860 pr_alert(DRV_PFX
"%s: out of memory\n", __func__
);
862 kfree(blkbk
->pending_reqs
);
863 kfree(blkbk
->pending_grant_handles
);
864 if (blkbk
->pending_pages
) {
865 for (i
= 0; i
< mmap_pages
; i
++) {
866 if (blkbk
->pending_pages
[i
])
867 __free_page(blkbk
->pending_pages
[i
]);
869 kfree(blkbk
->pending_pages
);
876 module_init(xen_blkif_init
);
878 MODULE_LICENSE("Dual BSD/GPL");
879 MODULE_ALIAS("xen-backend:vbd");