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block: Support AIO drivers in bdrv_driver_preadv/pwritev()

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Instead of registering emulation functions as .bdrv_co_writev, just
directly check whether the function is there or not, and use the AIO
interface if it isn't. This makes the read/write functions more
consistent with how things are done in other places (flush, discard,
etc.)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-04-25 14:13:12 +02:00
parent 78a07294d5
commit 0884447382
2 changed files with 52 additions and 75 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

126
block/io.c
View File

@ -40,12 +40,6 @@ static BlockAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
static BlockAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockCompletionFunc *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 BlockAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
@ -112,19 +106,13 @@ void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group)
void bdrv_setup_io_funcs(BlockDriver *bdrv)
{
/* Block drivers without coroutine functions need emulation */
if (!bdrv->bdrv_co_readv) {
bdrv->bdrv_co_readv = bdrv_co_readv_em;
bdrv->bdrv_co_writev = bdrv_co_writev_em;
/* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
* the block driver lacks aio we need to emulate that too.
*/
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;
}
/* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
* the block driver lacks aio we need to emulate that.
*/
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;
}
}
@ -797,6 +785,19 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
return 0;
}
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_driver_preadv(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
@ -809,7 +810,23 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS);
return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
if (drv->bdrv_co_readv) {
return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
} else {
BlockAIOCB *acb;
CoroutineIOCompletion co = {
.coroutine = qemu_coroutine_self(),
};
acb = bs->drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
bdrv_co_io_em_complete, &co);
if (acb == NULL) {
return -EIO;
} else {
qemu_coroutine_yield();
return co.ret;
}
}
}
static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
@ -828,9 +845,23 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
if (drv->bdrv_co_writev_flags) {
ret = drv->bdrv_co_writev_flags(bs, sector_num, nb_sectors, qiov,
flags);
} else {
} else if (drv->bdrv_co_writev) {
assert(drv->supported_write_flags == 0);
ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
} else {
BlockAIOCB *acb;
CoroutineIOCompletion co = {
.coroutine = qemu_coroutine_self(),
};
acb = bs->drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors,
bdrv_co_io_em_complete, &co);
if (acb == NULL) {
return -EIO;
} else {
qemu_coroutine_yield();
return co.ret;
}
}
if (ret == 0 && (flags & BDRV_REQ_FUA) &&
@ -2348,59 +2379,6 @@ void qemu_aio_unref(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(),
};
BlockAIOCB *acb;
if (is_write) {
acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors,
bdrv_co_io_em_complete, &co);
} else {
acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors,
bdrv_co_io_em_complete, &co);
}
trace_bdrv_co_io_em(bs, sector_num, nb_sectors, 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);
}
static void coroutine_fn bdrv_flush_co_entry(void *opaque)
{
RwCo *rwco = opaque;

1
trace-events
View File

@ -74,7 +74,6 @@ bdrv_co_copy_on_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector
bdrv_co_readv_no_serialising(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_write_zeroes(void *bs, int64_t sector_num, int nb_sector, int flags) "bs %p sector_num %"PRId64" nb_sectors %d flags %#x"
bdrv_co_io_em(void *bs, int64_t sector_num, int nb_sectors, int is_write, void *acb) "bs %p sector_num %"PRId64" nb_sectors %d is_write %d acb %p"
bdrv_co_do_copy_on_readv(void *bs, int64_t sector_num, int nb_sectors, int64_t cluster_sector_num, int cluster_nb_sectors) "bs %p sector_num %"PRId64" nb_sectors %d cluster_sector_num %"PRId64" cluster_nb_sectors %d"
# block/stream.c