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author | Paolo Bonzini <pbonzini@redhat.com> | 2022-04-14 19:57:55 +0200 |
---|---|---|
committer | Eric Blake <eblake@redhat.com> | 2022-04-26 13:16:41 -0500 |
commit | a80a9a1c7397382fc4c4e6feaa8242b25cadb519 (patch) | |
tree | 2f717189fe6409c22cdf0f9599c6ba10a3000032 /block/nbd.c | |
parent | dba5156c0e9c0362b7c6121f9e1c89bb9be1f227 (diff) | |
download | qemu-a80a9a1c7397382fc4c4e6feaa8242b25cadb519.zip qemu-a80a9a1c7397382fc4c4e6feaa8242b25cadb519.tar.gz qemu-a80a9a1c7397382fc4c4e6feaa8242b25cadb519.tar.bz2 |
nbd: take receive_mutex when reading requests[].receiving
requests[].receiving is set by nbd_receive_replies() under the receive_mutex;
Read it under the same mutex as well. Waking up receivers on errors happens
after each reply finishes processing, in nbd_co_receive_one_chunk().
If there is no currently-active reply, there are two cases:
* either there is no active request at all, in which case no
element of request[] can have .receiving = true
* or nbd_receive_replies() must be running and owns receive_mutex;
in that case it will get back to nbd_co_receive_one_chunk() because
the socket has been shutdown, and all waiting coroutines will wake up
in turn.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220414175756.671165-9-pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'block/nbd.c')
-rw-r--r-- | block/nbd.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/block/nbd.c b/block/nbd.c index a5c690c..3bfcf4d 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -131,6 +131,7 @@ static void nbd_clear_bdrvstate(BlockDriverState *bs) s->x_dirty_bitmap = NULL; } +/* Called with s->receive_mutex taken. */ static bool coroutine_fn nbd_recv_coroutine_wake_one(NBDClientRequest *req) { if (req->receiving) { @@ -142,12 +143,13 @@ static bool coroutine_fn nbd_recv_coroutine_wake_one(NBDClientRequest *req) return false; } -static void coroutine_fn nbd_recv_coroutines_wake(BDRVNBDState *s, bool all) +static void coroutine_fn nbd_recv_coroutines_wake(BDRVNBDState *s) { int i; + QEMU_LOCK_GUARD(&s->receive_mutex); for (i = 0; i < MAX_NBD_REQUESTS; i++) { - if (nbd_recv_coroutine_wake_one(&s->requests[i]) && !all) { + if (nbd_recv_coroutine_wake_one(&s->requests[i])) { return; } } @@ -168,8 +170,6 @@ static void coroutine_fn nbd_channel_error_locked(BDRVNBDState *s, int ret) } else { s->state = NBD_CLIENT_QUIT; } - - nbd_recv_coroutines_wake(s, true); } static void coroutine_fn nbd_channel_error(BDRVNBDState *s, int ret) @@ -432,11 +432,10 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t handle) qemu_coroutine_yield(); /* - * We may be woken for 3 reasons: + * We may be woken for 2 reasons: * 1. From this function, executing in parallel coroutine, when our * handle is received. - * 2. From nbd_channel_error(), when connection is lost. - * 3. From nbd_co_receive_one_chunk(), when previous request is + * 2. From nbd_co_receive_one_chunk(), when previous request is * finished and s->reply.handle set to 0. * Anyway, it's OK to lock the mutex and go to the next iteration. */ @@ -928,7 +927,7 @@ static coroutine_fn int nbd_co_receive_one_chunk( } s->reply.handle = 0; - nbd_recv_coroutines_wake(s, false); + nbd_recv_coroutines_wake(s); return ret; } |