| From fa9d637c3213e638a515035dd73cadc315589cbe Mon Sep 17 00:00:00 2001 |
| From: Roland Dreier <roland@purestorage.com> |
| Date: Tue, 22 Mar 2011 16:35:10 -0700 |
| Subject: [PATCH] aio: wake all waiters when destroying ctx |
| |
| commit e91f90bb0bb10be9cc8efd09a3cf4ecffcad0db1 upstream. |
| |
| The test program below will hang because io_getevents() uses |
| add_wait_next_round_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 <libaio.h> |
| #include <pthread.h> |
| #include <stdio.h> |
| #include <unistd.h> |
| |
| 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 <roland@purestorage.com> |
| Reviewed-by: Jeff Moyer <jmoyer@redhat.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/fs/aio.c b/fs/aio.c |
| index 94b6cd6..2600146 100644 |
| --- a/fs/aio.c |
| +++ b/fs/aio.c |
| @@ -512,7 +512,7 @@ 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) |
| @@ -1225,7 +1225,7 @@ 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 */ |
| } |
| |
| -- |
| 1.7.4.4 |
| |