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[Qemu-devel] [RFC][PATCH 3/9] block: Add bdrv_co_readv/writev emulation
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [RFC][PATCH 3/9] block: Add bdrv_co_readv/writev emulation |
Date: |
Fri, 15 Jul 2011 18:47:33 +0200 |
In order to be able to call bdrv_co_readv/writev for drivers that don't
implement the functions natively, add an emulation that uses the AIO functions
to implement them.
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++------
trace-events | 1 +
2 files changed, 78 insertions(+), 9 deletions(-)
diff --git a/block.c b/block.c
index 79a5008..fc1712f 100644
--- a/block.c
+++ b/block.c
@@ -64,6 +64,12 @@ static BlockDriverAIOCB
*bdrv_co_aio_readv_em(BlockDriverState *bs,
static BlockDriverAIOCB *bdrv_co_aio_writev_em(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
+static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov);
+static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov);
static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
QTAILQ_HEAD_INITIALIZER(bdrv_states);
@@ -182,14 +188,19 @@ void bdrv_register(BlockDriver *bdrv)
bdrv->bdrv_aio_writev = bdrv_co_aio_writev_em;
bdrv->bdrv_read = bdrv_read_em;
bdrv->bdrv_write = bdrv_write_em;
- } else if (!bdrv->bdrv_aio_readv) {
- /* add AIO emulation layer */
- bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
- bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
- } else if (!bdrv->bdrv_read) {
- /* add synchronous IO emulation layer */
- bdrv->bdrv_read = bdrv_read_em;
- bdrv->bdrv_write = bdrv_write_em;
+ } else {
+ bdrv->bdrv_co_readv = bdrv_co_readv_em;
+ bdrv->bdrv_co_writev = bdrv_co_writev_em;
+
+ if (!bdrv->bdrv_aio_readv) {
+ /* add AIO emulation layer */
+ bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
+ bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
+ } else if (!bdrv->bdrv_read) {
+ /* add synchronous IO emulation layer */
+ bdrv->bdrv_read = bdrv_read_em;
+ bdrv->bdrv_write = bdrv_write_em;
+ }
}
if (!bdrv->bdrv_aio_flush)
@@ -2652,7 +2663,7 @@ static void coroutine_fn bdrv_co_rw(void *opaque)
BlockDriverAIOCBCoroutine *acb = opaque;
BlockDriverState *bs = acb->common.bs;
- if (acb->is_write) {
+ if (!acb->is_write) {
acb->req.error = bs->drv->bdrv_co_readv(bs, acb->req.sector,
acb->req.nb_sectors, acb->req.qiov);
} else {
@@ -2849,6 +2860,63 @@ void qemu_aio_release(void *p)
}
/**************************************************************/
+/* Coroutine block device emulation */
+
+typedef struct CoroutineIOCompletion {
+ Coroutine *coroutine;
+ int ret;
+} CoroutineIOCompletion;
+
+static void bdrv_co_io_em_complete(void *opaque, int ret)
+{
+ CoroutineIOCompletion *co = opaque;
+
+ co->ret = ret;
+ qemu_coroutine_enter(co->coroutine, NULL);
+}
+
+static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *iov,
+ bool is_write)
+{
+ CoroutineIOCompletion co = {
+ .coroutine = qemu_coroutine_self(),
+ .ret = -EINPROGRESS,
+ };
+ BlockDriverAIOCB *acb;
+
+ if (is_write) {
+ acb = bdrv_aio_writev(bs, sector_num, iov, nb_sectors,
+ bdrv_co_io_em_complete, &co);
+ } else {
+ acb = bdrv_aio_readv(bs, sector_num, iov, nb_sectors,
+ bdrv_co_io_em_complete, &co);
+ }
+
+ trace_bdrv_co_io(is_write, acb);
+ if (!acb) {
+ return -EIO;
+ }
+ qemu_coroutine_yield();
+
+ return co.ret;
+}
+
+static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov)
+{
+ return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false);
+}
+
+static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors,
+ QEMUIOVector *iov)
+{
+ return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);
+}
+
+/**************************************************************/
/* removable device support */
/**
diff --git a/trace-events b/trace-events
index 3cd9118..b835c61 100644
--- a/trace-events
+++ b/trace-events
@@ -57,6 +57,7 @@ disable bdrv_aio_writev(void *bs, int64_t sector_num, int
nb_sectors, void *opaq
disable bdrv_set_locked(void *bs, int locked) "bs %p locked %d"
disable bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p
sector_num %"PRId64" nb_sectors %d"
disable bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p
sector_num %"PRId64" nb_sectors %d"
+disable bdrv_co_io(int is_write, void *acb) "is_write %d acb %p"
# hw/virtio-blk.c
disable virtio_blk_req_complete(void *req, int status) "req %p status %d"
--
1.7.6
- [Qemu-devel] [RFC][PATCH 0/9] Use coroutines in the block layer, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 1/9] block: Add bdrv_co_readv/writev, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 2/9] block: Emulate AIO functions with bdrv_co_readv/writev, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 3/9] block: Add bdrv_co_readv/writev emulation,
Kevin Wolf <=
- [Qemu-devel] [RFC][PATCH 4/9] coroutines: Locks, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 5/9] qcow2: Use coroutines, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 6/9] qcow: Use coroutines, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 8/9] coroutines: Use one global bottom half for CoQueue, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 7/9] async: Remove AsyncContext, Kevin Wolf, 2011/07/15
- [Qemu-devel] [RFC][PATCH 9/9] block: Use bdrv_co_* instead of synchronous versions in coroutines, Kevin Wolf, 2011/07/15