diff options
author | Stefan Hajnoczi <stefanha@redhat.com> | 2023-03-07 16:04:26 -0500 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2023-04-25 13:15:21 +0200 |
commit | ef80ec5067d7ca5b46e5b88be1be33cddfd33551 (patch) | |
tree | e34b78dcb1dbdad2cdf7618ab3ac03670d838128 | |
parent | c4d5bf99b7fccf8849316b9f5100525b1beb8237 (diff) | |
download | qemu-ef80ec5067d7ca5b46e5b88be1be33cddfd33551.zip qemu-ef80ec5067d7ca5b46e5b88be1be33cddfd33551.tar.gz qemu-ef80ec5067d7ca5b46e5b88be1be33cddfd33551.tar.bz2 |
block: make BlockBackend->disable_request_queuing atomic
This field is accessed by multiple threads without a lock. Use explicit
qatomic_read()/qatomic_set() calls. There is no need for acquire/release
because blk_set_disable_request_queuing() doesn't provide any
guarantees (it helps that it's used at BlockBackend creation time and
not when there is I/O in flight).
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230307210427.269214-3-stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r-- | block/block-backend.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index 2ae768f..8552b6d 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -82,7 +82,7 @@ struct BlockBackend { int quiesce_counter; /* atomic: written under BQL, read by other threads */ CoQueue queued_requests; - bool disable_request_queuing; + bool disable_request_queuing; /* atomic */ VMChangeStateEntry *vmsh; bool force_allow_inactivate; @@ -1232,7 +1232,7 @@ void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow) void blk_set_disable_request_queuing(BlockBackend *blk, bool disable) { IO_CODE(); - blk->disable_request_queuing = disable; + qatomic_set(&blk->disable_request_queuing, disable); } static int coroutine_fn GRAPH_RDLOCK @@ -1271,7 +1271,8 @@ static void coroutine_fn blk_wait_while_drained(BlockBackend *blk) { assert(blk->in_flight > 0); - if (qatomic_read(&blk->quiesce_counter) && !blk->disable_request_queuing) { + if (qatomic_read(&blk->quiesce_counter) && + !qatomic_read(&blk->disable_request_queuing)) { blk_dec_in_flight(blk); qemu_co_queue_wait(&blk->queued_requests, NULL); blk_inc_in_flight(blk); |