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nfs: Run co BH CB in the coroutine’s AioContext

Browse source 
Like in “rbd: Run co BH CB in the coroutine’s AioContext”, drop the
completion flag, yield exactly once, and run the BH in the coroutine’s
AioContext.

(Can be reproduced with multiqueue by adding a usleep(100000) before the
`while (!task.complete)` loops.)

Like in “iscsi: Run co BH CB in the coroutine’s AioContext”, this makes
nfs_co_generic_bh_cb() trivial, so we can drop it in favor of just
calling aio_co_wake() directly.

Cc: qemu-stable@nongnu.org
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20251110154854.151484-5-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Hanna Czenczek 2025-11-10 16:48:39 +01:00 • committed by Kevin Wolf
parent a9500527db
commit deb35c129b
1 changed files with 16 additions and 25 deletions
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33
block/nfs.c
View file

@ -69,7 +69,6 @@ typedef struct NFSClient {
typedef struct NFSRPC {
BlockDriverState *bs;
int ret;
int complete;
QEMUIOVector *iov;
struct stat *st;
Coroutine *co;
@ -230,14 +229,6 @@ static void coroutine_fn nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
};
}
static void nfs_co_generic_bh_cb(void *opaque)
{
NFSRPC *task = opaque;
task->complete = 1;
aio_co_wake(task->co);
}
/* Called (via nfs_service) with QemuMutex held. */
static void
nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
@ -256,8 +247,16 @@ nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
if (task->ret < 0) {
error_report("NFS Error: %s", nfs_get_error(nfs));
}
replay_bh_schedule_oneshot_event(task->client->aio_context,
nfs_co_generic_bh_cb, task);
/*
* Safe to call: nfs_service(), which called us, is only run from the FD
* handlers, never from the request coroutine. The request coroutine in
* turn will yield unconditionally.
* No need to release the lock, even if we directly enter the coroutine, as
* the lock is never re-taken after yielding. (Note: If we do enter the
* coroutine, @task will probably be dangling once aio_co_wake() returns.)
*/
aio_co_wake(task->co);
}
static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset,
@ -278,9 +277,7 @@ static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset,
nfs_set_events(client);
}
while (!task.complete) {
qemu_coroutine_yield();
}
if (task.ret < 0) {
return task.ret;
@ -328,9 +325,7 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, int64_t offset,
nfs_set_events(client);
}
while (!task.complete) {
qemu_coroutine_yield();
}
if (my_buffer) {
g_free(buf);
@ -358,9 +353,7 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
nfs_set_events(client);
}
while (!task.complete) {
qemu_coroutine_yield();
}
return task.ret;
}
@ -723,8 +716,8 @@ nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
if (task->ret < 0) {
error_report("NFS Error: %s", nfs_get_error(nfs));
}
replay_bh_schedule_oneshot_event(task->client->aio_context,
nfs_co_generic_bh_cb, task);
/* Safe to call, see nfs_co_generic_cb() */
aio_co_wake(task->co);
}
static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs)
@ -748,9 +741,7 @@ static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs)
nfs_set_events(client);
}
while (!task.complete) {
qemu_coroutine_yield();
}
return (task.ret < 0 ? task.ret : st.st_blocks * 512);
}