From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751859Ab1CKFz4 (ORCPT ); Fri, 11 Mar 2011 00:55:56 -0500 Received: from na3sys010aog102.obsmtp.com ([74.125.245.72]:60155 "HELO na3sys010aog102.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751358Ab1CKFzz (ORCPT ); Fri, 11 Mar 2011 00:55:55 -0500 From: Roland Dreier To: Andrew Morton Cc: linux-aio@kvack.org, linux-kernel@vger.kernel.org, Benjamin LaHaise , Jeff Moyer Subject: [PATCH] aio: Wake all waiters when destroying ctx Date: Thu, 10 Mar 2011 21:55:37 -0800 Message-Id: <1299822937-6522-1-git-send-email-roland@kernel.org> X-Mailer: git-send-email 1.7.4.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Roland Dreier The test program below will hang because io_getevents() uses add_wait_queue_exclusive(), which means the wake_up() in io_destroy() only wakes up one of the threads. Fix this by using wake_up_all() in the aio code paths where we want to make sure no one gets stuck. // t.c -- compile with gcc -lpthread -laio t.c #include #include #include #include static const int nthr = 2; void *getev(void *ctx) { struct io_event ev; io_getevents(ctx, 1, 1, &ev, NULL); printf("io_getevents returned\n"); return NULL; } int main(int argc, char *argv[]) { io_context_t ctx = 0; pthread_t thread[nthr]; int i; io_setup(1024, &ctx); for (i = 0; i < nthr; ++i) pthread_create(&thread[i], NULL, getev, ctx); sleep(1); io_destroy(ctx); for (i = 0; i < nthr; ++i) pthread_join(thread[i], NULL); return 0; } Cc: Signed-off-by: Roland Dreier --- fs/aio.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 26869cd..88f0ed5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -520,7 +520,7 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) ctx->reqs_active--; if (unlikely(!ctx->reqs_active && ctx->dead)) - wake_up(&ctx->wait); + wake_up_all(&ctx->wait); } static void aio_fput_routine(struct work_struct *data) @@ -1229,7 +1229,7 @@ static void io_destroy(struct kioctx *ioctx) * by other CPUs at this point. Right now, we rely on the * locking done by the above calls to ensure this consistency. */ - wake_up(&ioctx->wait); + wake_up_all(&ioctx->wait); put_ioctx(ioctx); /* once for the lookup */ }