On Thu, 10/13 19:34, Paolo Bonzini wrote:
> We want the BDS event loop to run exclusively in the iothread that
> owns the BDS's AioContext. This function and macro provides the
> synchronization between the two event loops.
>
> Signed-off-by: Paolo Bonzini
> ---
> block/block-backend.c | 7 +--
> block/io.c| 47
> +++
> block/qed-table.c | 16
> block/qed.c | 4 +++-
> include/block/block.h | 9 +
> include/block/block_int.h | 1 +
> 6 files changed, 29 insertions(+), 55 deletions(-)
>
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 234df1e..c5c2597 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -878,7 +878,6 @@ static int blk_prw(BlockBackend *blk, int64_t offset,
> uint8_t *buf,
> int64_t bytes, CoroutineEntry co_entry,
> BdrvRequestFlags flags)
> {
> -AioContext *aio_context;
> QEMUIOVector qiov;
> struct iovec iov;
> Coroutine *co;
> @@ -900,11 +899,7 @@ static int blk_prw(BlockBackend *blk, int64_t offset,
> uint8_t *buf,
>
> co = qemu_coroutine_create(co_entry, &rwco);
> qemu_coroutine_enter(co);
> -
> -aio_context = blk_get_aio_context(blk);
> -while (rwco.ret == NOT_DONE) {
> -aio_poll(aio_context, true);
> -}
> +bdrv_poll_while(blk_bs(blk), rwco.ret == NOT_DONE);
Can we make it "BDRV_POLL_WHILE"? With lower case the mental model of a reader
would be "evaluate rwco.ret == NOT_DONE" first before doing the poll.
>
> return rwco.ret;
> }
> diff --git a/block/io.c b/block/io.c
> index afec968..7d3dcfc 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -156,23 +156,12 @@ bool bdrv_requests_pending(BlockDriverState *bs)
> return false;
> }
>
> -static bool bdrv_drain_poll(BlockDriverState *bs)
> -{
> -bool waited = false;
> -
> -while (atomic_read(&bs->in_flight) > 0) {
> -aio_poll(bdrv_get_aio_context(bs), true);
> -waited = true;
> -}
> -return waited;
> -}
> -
> static bool bdrv_drain_recurse(BlockDriverState *bs)
> {
> BdrvChild *child;
> bool waited;
>
> -waited = bdrv_drain_poll(bs);
> +waited = bdrv_poll_while(bs, atomic_read(&bs->in_flight) > 0);
>
> if (bs->drv && bs->drv->bdrv_drain) {
> bs->drv->bdrv_drain(bs);
> @@ -485,9 +474,14 @@ void bdrv_inc_in_flight(BlockDriverState *bs)
> atomic_inc(&bs->in_flight);
> }
>
> +void bdrv_wakeup(BlockDriverState *bs)
> +{
> +}
> +
> void bdrv_dec_in_flight(BlockDriverState *bs)
> {
> atomic_dec(&bs->in_flight);
> +bdrv_wakeup(bs);
> }
>
> static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
> @@ -597,13 +591,9 @@ static int bdrv_prwv_co(BdrvChild *child, int64_t offset,
> /* Fast-path if already in coroutine context */
> bdrv_rw_co_entry(&rwco);
> } else {
> -AioContext *aio_context = bdrv_get_aio_context(child->bs);
> -
> co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco);
> qemu_coroutine_enter(co);
> -while (rwco.ret == NOT_DONE) {
> -aio_poll(aio_context, true);
> -}
> +bdrv_poll_while(child->bs, rwco.ret == NOT_DONE);
> }
> return rwco.ret;
> }
> @@ -1845,14 +1835,10 @@ int64_t bdrv_get_block_status_above(BlockDriverState
> *bs,
> /* Fast-path if already in coroutine context */
> bdrv_get_block_status_above_co_entry(&data);
> } else {
> -AioContext *aio_context = bdrv_get_aio_context(bs);
> -
> co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry,
> &data);
> qemu_coroutine_enter(co);
> -while (!data.done) {
> -aio_poll(aio_context, true);
> -}
> +bdrv_poll_while(bs, !data.done);
> }
> return data.ret;
> }
> @@ -2411,13 +2397,9 @@ int bdrv_flush(BlockDriverState *bs)
> /* Fast-path if already in coroutine context */
> bdrv_flush_co_entry(&flush_co);
> } else {
> -AioContext *aio_context = bdrv_get_aio_context(bs);
> -
> co = qemu_coroutine_create(bdrv_flush_co_entry, &flush_co);
> qemu_coroutine_enter(co);
> -while (flush_co.ret == NOT_DONE) {
> -aio_poll(aio_context, true);
> -}
> +bdrv_poll_while(bs, flush_co.ret == NOT_DONE);
> }
>
> return flush_co.ret;
> @@ -2543,13 +2525,9 @@ int bdrv_pdiscard(BlockDriverState *bs, int64_t
> offset, int count)
> /* Fast-path if already in coroutine context */
> bdrv_pdiscard_co_entry(&rwco);
> } else {
> -AioContext *aio_context = bdrv_get_aio_context(bs);
> -
> co = qemu_coroutine_create(bdrv_pdiscard_co_entry, &rwco);
> qemu_coroutine_enter(co);
> -while (rwco.ret == NOT_DONE) {
> -aio_poll(aio_context, true);
