From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54839) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a1Hvb-0002Uj-DY for qemu-devel@nongnu.org; Tue, 24 Nov 2015 13:02:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a1Hva-0006Ay-Ck for qemu-devel@nongnu.org; Tue, 24 Nov 2015 13:02:55 -0500 From: Paolo Bonzini Date: Tue, 24 Nov 2015 19:01:30 +0100 Message-Id: <1448388091-117282-40-git-send-email-pbonzini@redhat.com> In-Reply-To: <1448388091-117282-1-git-send-email-pbonzini@redhat.com> References: <1448388091-117282-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 39/40] async: remove unnecessary inc/dec pairs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, qemu-block@nongnu.org Pull the increment/decrement pair out of aio_bh_poll and into the callers. Signed-off-by: Paolo Bonzini --- aio-posix.c | 7 ++----- aio-win32.c | 9 ++++++--- async.c | 12 ++++++------ 3 files changed, 14 insertions(+), 14 deletions(-) diff --git a/aio-posix.c b/aio-posix.c index b372816..23dcbaa 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -346,9 +346,8 @@ static bool aio_dispatch_handlers(AioContext *ctx) void aio_dispatch(AioContext *ctx) { - aio_bh_poll(ctx); - qemu_lockcnt_inc(&ctx->list_lock); + aio_bh_poll(ctx); aio_dispatch_handlers(ctx); qemu_lockcnt_dec(&ctx->list_lock); @@ -461,12 +460,10 @@ bool aio_poll(AioContext *ctx, bool blocking) } npfd = 0; - qemu_lockcnt_dec(&ctx->list_lock); progress |= aio_bh_poll(ctx); - - qemu_lockcnt_inc(&ctx->list_lock); progress |= aio_dispatch_handlers(ctx); + qemu_lockcnt_dec(&ctx->list_lock); progress |= timerlistgroup_run_timers(&ctx->tlg); diff --git a/aio-win32.c b/aio-win32.c index feffdc4..36d39f7 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -231,8 +231,6 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) AioHandler *node; bool progress = false; - qemu_lockcnt_inc(&ctx->list_lock); - /* * We have to walk very carefully in case aio_set_fd_handler is * called while we're walking. @@ -282,14 +280,15 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event) } } - qemu_lockcnt_dec(&ctx->list_lock); return progress; } void aio_dispatch(AioContext *ctx) { + qemu_lockcnt_inc(&ctx->list_lock); aio_bh_poll(ctx); aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE); + qemu_lockcnt_dec(&ctx->list_lock); timerlistgroup_run_timers(&ctx->tlg); } @@ -350,6 +349,7 @@ bool aio_poll(AioContext *ctx, bool blocking) if (first) { aio_notify_accept(ctx); + qemu_lockcnt_inc(&ctx->list_lock); progress |= aio_bh_poll(ctx); first = false; } @@ -369,6 +369,9 @@ bool aio_poll(AioContext *ctx, bool blocking) progress |= aio_dispatch_handlers(ctx, event); } while (count > 0); + assert(!first); /* and lockcnt incremented */ + qemu_lockcnt_dec(&ctx->list_lock); + progress |= timerlistgroup_run_timers(&ctx->tlg); return progress; diff --git a/async.c b/async.c index 529934c..db05243 100644 --- a/async.c +++ b/async.c @@ -64,15 +64,16 @@ void aio_bh_call(QEMUBH *bh) bh->cb(bh->opaque); } -/* Multiple occurrences of aio_bh_poll cannot be called concurrently */ +/* Multiple occurrences of aio_bh_poll cannot be called concurrently. + * The count in ctx->list_lock is incremented before the call, and is + * not affected by the call. + */ int aio_bh_poll(AioContext *ctx) { QEMUBH *bh, **bhp, *next; int ret; bool deleted = false; - qemu_lockcnt_inc(&ctx->list_lock); - ret = 0; for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) { next = atomic_rcu_read(&bh->next); @@ -98,11 +99,10 @@ int aio_bh_poll(AioContext *ctx) /* remove deleted bhs */ if (!deleted) { - qemu_lockcnt_dec(&ctx->list_lock); return ret; } - if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) { + if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) { bhp = &ctx->first_bh; while (*bhp) { bh = *bhp; @@ -113,7 +113,7 @@ int aio_bh_poll(AioContext *ctx) bhp = &bh->next; } } - qemu_lockcnt_unlock(&ctx->list_lock); + qemu_lockcnt_inc_and_unlock(&ctx->list_lock); } return ret; } -- 1.8.3.1