From e91f90bb0bb10be9cc8efd09a3cf4ecffcad0db1 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Tue, 22 Mar 2011 16:35:10 -0700 Subject: [PATCH] aio: wake all waiters when destroying ctx 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; } Signed-off-by: Roland Dreier Reviewed-by: Jeff Moyer Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/aio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 7f54f43b8f7..ebb6a22e4e1 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 */ } -- 2.20.1