From 6b5cfed21e20b372090046a934387255ff4bda58 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 5 Dec 2023 13:20:01 -0500 Subject: [PATCH 084/101] aio: make aio_context_acquire()/aio_context_release() a no-op RH-Author: Kevin Wolf RH-MergeRequest: 214: Remove AioContext lock RH-Jira: RHEL-15965 RH-Acked-by: Miroslav Rezanina RH-Acked-by: Stefan Hajnoczi RH-Commit: [15/26] 723dcada900aaf08862e8221921be22506b561a8 (kmwolf/centos-qemu-kvm) aio_context_acquire()/aio_context_release() has been replaced by fine-grained locking to protect state shared by multiple threads. The AioContext lock still plays the role of balancing locking in AIO_WAIT_WHILE() and many functions in QEMU either require that the AioContext lock is held or not held for this reason. In other words, the AioContext lock is purely there for consistency with itself and serves no real purpose anymore. Stop actually acquiring/releasing the lock in aio_context_acquire()/aio_context_release() so that subsequent patches can remove callers across the codebase incrementally. I have performed "make check" and qemu-iotests stress tests across x86-64, ppc64le, and aarch64 to confirm that there are no failures as a result of eliminating the lock. Signed-off-by: Stefan Hajnoczi Reviewed-by: Eric Blake Acked-by: Kevin Wolf Message-ID: <20231205182011.1976568-5-stefanha@redhat.com> Signed-off-by: Kevin Wolf --- util/async.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/util/async.c b/util/async.c index 8f90ddc304..04ee83d220 100644 --- a/util/async.c +++ b/util/async.c @@ -725,12 +725,12 @@ void aio_context_unref(AioContext *ctx) void aio_context_acquire(AioContext *ctx) { - qemu_rec_mutex_lock(&ctx->lock); + /* TODO remove this function */ } void aio_context_release(AioContext *ctx) { - qemu_rec_mutex_unlock(&ctx->lock); + /* TODO remove this function */ } QEMU_DEFINE_STATIC_CO_TLS(AioContext *, my_aiocontext) -- 2.39.3