Commit 936af157 authored by Al Viro's avatar Al Viro
Browse files

aio: don't bother with unmapping when aio_free_ring() is coming from exit_aio() 



... since exit_mmap() is coming and it will munmap() everything anyway.
In all other cases aio_free_ring() has ctx->mm == current->mm; moreover,
all other callers of vm_munmap() have mm == current->mm, so this will
allow us to get rid of mm argument of vm_munmap().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6be5ceb0

fs/aio.c

+14 −1
Original line number Diff line number Diff line
@@ -92,8 +92,10 @@ static void aio_free_ring(struct kioctx *ctx) 
	for (i=0; i<info->nr_pages; i++)

		put_page(info->ring_pages[i]);



	if (info->mmap_size)

	if (info->mmap_size) {

		BUG_ON(ctx->mm != current->mm);

		vm_munmap(ctx->mm, info->mmap_base, info->mmap_size);

	}



	if (info->ring_pages && info->ring_pages != info->internal_pages)

		kfree(info->ring_pages);
@@ -386,6 +388,17 @@ void exit_aio(struct mm_struct *mm) 
				"exit_aio:ioctx still alive: %d %d %d\n",

				atomic_read(&ctx->users), ctx->dead,

				ctx->reqs_active);

		/*

		 * We don't need to bother with munmap() here -

		 * exit_mmap(mm) is coming and it'll unmap everything.

		 * Since aio_free_ring() uses non-zero ->mmap_size

		 * as indicator that it needs to unmap the area,

		 * just set it to 0; aio_free_ring() is the only

		 * place that uses ->mmap_size, so it's safe.

		 * That way we get all munmap done to current->mm -

		 * all other callers have ctx->mm == current->mm.

		 */

		ctx->ring_info.mmap_size = 0;

		put_ioctx(ctx);

	}

}

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