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[Qemu-devel] [PATCH 09/22] block: Introduce bdrv_aligned_preadv()
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 09/22] block: Introduce bdrv_aligned_preadv() |
Date: |
Wed, 11 Dec 2013 22:08:16 +0100 |
This separates the part of bdrv_co_do_readv() that needs to happen
before the request is modified to match the backend alignment, and a
part that needs to be executed afterwards and passes the request to the
BlockDriver.
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 61 +++++++++++++++++++++++++++++++++++++++++++------------------
1 file changed, 43 insertions(+), 18 deletions(-)
diff --git a/block.c b/block.c
index b86e754..cbc9f6d 100644
--- a/block.c
+++ b/block.c
@@ -2700,26 +2700,24 @@ err:
}
/*
- * Handle a read request in coroutine context
+ * Forwards an already correctly aligned request to the BlockDriver. This
+ * handles copy on read and zeroing after EOF; any other features must be
+ * implemented by the caller.
*/
-static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
- BdrvRequestFlags flags)
+static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)
{
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
int ret;
- if (!drv) {
- return -ENOMEDIUM;
- }
- if (bdrv_check_request(bs, sector_num, nb_sectors)) {
- return -EIO;
- }
+ int64_t sector_num = offset >> BDRV_SECTOR_BITS;
+ unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
- if (bs->copy_on_read) {
- flags |= BDRV_REQ_COPY_ON_READ;
- }
+ assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
+ assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
+
+ /* Handle Copy on Read and associated serialisation */
if (flags & BDRV_REQ_COPY_ON_READ) {
bs->copy_on_read_in_flight++;
}
@@ -2728,11 +2726,6 @@ static int coroutine_fn
bdrv_co_do_readv(BlockDriverState *bs,
wait_for_overlapping_requests(bs, sector_num, nb_sectors);
}
- /* throttling disk I/O */
- if (bs->io_limits_enabled) {
- bdrv_io_limits_intercept(bs, nb_sectors, false);
- }
-
tracked_request_begin(&req, bs, sector_num, nb_sectors, false);
if (flags & BDRV_REQ_COPY_ON_READ) {
@@ -2749,6 +2742,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState
*bs,
}
}
+ /* Forward the request to the BlockDriver */
if (!(bs->zero_beyond_eof && bs->growable)) {
ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
} else {
@@ -2789,6 +2783,37 @@ out:
return ret;
}
+/*
+ * Handle a read request in coroutine context
+ */
+static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
+ BdrvRequestFlags flags)
+{
+ BlockDriver *drv = bs->drv;
+ int ret;
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+ if (bdrv_check_request(bs, sector_num, nb_sectors)) {
+ return -EIO;
+ }
+
+ if (bs->copy_on_read) {
+ flags |= BDRV_REQ_COPY_ON_READ;
+ }
+
+ /* throttling disk I/O */
+ if (bs->io_limits_enabled) {
+ bdrv_io_limits_intercept(bs, nb_sectors, false);
+ }
+
+ ret = bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS,
+ nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
+ return ret;
+}
+
int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
--
1.8.1.4
- Re: [Qemu-devel] [PATCH 04/22] qemu_memalign: Allow small alignments, (continued)
- [Qemu-devel] [PATCH 06/22] block: Don't use guest sector size for qemu_blockalign(), Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 01/22] block: Move initialisation of BlockLimits to bdrv_refresh_limits(), Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 03/22] block: Update BlockLimits when they might have changed, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 08/22] raw: Probe required direct I/O alignment, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 09/22] block: Introduce bdrv_aligned_preadv(),
Kevin Wolf <=
- [Qemu-devel] [PATCH 07/22] block: rename buffer_alignment to guest_block_size, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 10/22] block: Introduce bdrv_co_do_preadv(), Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 11/22] block: Introduce bdrv_aligned_pwritev(), Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 12/22] block: write: Handle COR dependency after I/O throttling, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 13/22] block: Introduce bdrv_co_do_pwritev(), Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 14/22] block: Switch BdrvTrackedRequest to byte granularity, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 16/22] block: Make zero-after-EOF work with larger alignment, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 15/22] block: Allow waiting for overlapping requests between begin/end, Kevin Wolf, 2013/12/11
- [Qemu-devel] [PATCH 17/22] block: Generalise and optimise COR serialisation, Kevin Wolf, 2013/12/11