Commit 715335d9 authored by Roland Dreier's avatar Roland Dreier Committed by Greg Kroah-Hartman

aio: wake all waiters when destroying ctx

commit e91f90bb upstream.

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 <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: default avatarRoland Dreier <roland@purestorage.com>
Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 34181407
...@@ -520,7 +520,7 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) ...@@ -520,7 +520,7 @@ static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
ctx->reqs_active--; ctx->reqs_active--;
if (unlikely(!ctx->reqs_active && ctx->dead)) 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) static void aio_fput_routine(struct work_struct *data)
...@@ -1229,7 +1229,7 @@ static void io_destroy(struct kioctx *ioctx) ...@@ -1229,7 +1229,7 @@ static void io_destroy(struct kioctx *ioctx)
* by other CPUs at this point. Right now, we rely on the * by other CPUs at this point. Right now, we rely on the
* locking done by the above calls to ensure this consistency. * 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 */ put_ioctx(ioctx); /* once for the lookup */
} }
......
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