diff mbox series

[v7,14/19] iomap: Fix iomap_dio_rw return value for user copies

Message ID 20210827164926.1726765-15-agruenba@redhat.com (mailing list archive)
State New, archived
Headers show
Series gfs2: Fix mmap + page fault deadlocks | expand

Commit Message

Andreas Gruenbacher Aug. 27, 2021, 4:49 p.m. UTC
When a user copy fails in one of the helpers of iomap_dio_rw, fail with
-EFAULT instead of returning 0.  This matches what iomap_dio_bio_actor
returns when it gets an -EFAULT from bio_iov_iter_get_pages.  With these
changes, iomap_dio_actor now consistently fails with -EFAULT when a user
page cannot be faulted in.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/iomap/direct-io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Darrick J. Wong Sept. 3, 2021, 6:54 p.m. UTC | #1
On Fri, Aug 27, 2021 at 06:49:21PM +0200, Andreas Gruenbacher wrote:
> When a user copy fails in one of the helpers of iomap_dio_rw, fail with
> -EFAULT instead of returning 0.  This matches what iomap_dio_bio_actor
> returns when it gets an -EFAULT from bio_iov_iter_get_pages.  With these
> changes, iomap_dio_actor now consistently fails with -EFAULT when a user
> page cannot be faulted in.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/iomap/direct-io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 9398b8c31323..8054f5d6c273 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -370,7 +370,7 @@ iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
>  {
>  	length = iov_iter_zero(length, dio->submit.iter);
>  	dio->size += length;
> -	return length;
> +	return length ? length : -EFAULT;
>  }
>  
>  static loff_t
> @@ -397,7 +397,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
>  		copied = copy_to_iter(iomap->inline_data + pos, length, iter);
>  	}
>  	dio->size += copied;
> -	return copied;
> +	return copied ? copied : -EFAULT;
>  }
>  
>  static loff_t
> -- 
> 2.26.3
>
Christoph Hellwig Sept. 9, 2021, 11:17 a.m. UTC | #2
On Fri, Aug 27, 2021 at 06:49:21PM +0200, Andreas Gruenbacher wrote:
> When a user copy fails in one of the helpers of iomap_dio_rw, fail with
> -EFAULT instead of returning 0.  This matches what iomap_dio_bio_actor
> returns when it gets an -EFAULT from bio_iov_iter_get_pages.  With these
> changes, iomap_dio_actor now consistently fails with -EFAULT when a user
> page cannot be faulted in.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> ---
>  fs/iomap/direct-io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 9398b8c31323..8054f5d6c273 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -370,7 +370,7 @@ iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
>  {
>  	length = iov_iter_zero(length, dio->submit.iter);
>  	dio->size += length;
> -	return length;
> +	return length ? length : -EFAULT;

What's wrong with a good old:

	if (!length)
		return -EFAULT;
	return length?

Besides this nit and the fact that the patch needs a reabse it looks
good to me:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 9398b8c31323..8054f5d6c273 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -370,7 +370,7 @@  iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio)
 {
 	length = iov_iter_zero(length, dio->submit.iter);
 	dio->size += length;
-	return length;
+	return length ? length : -EFAULT;
 }
 
 static loff_t
@@ -397,7 +397,7 @@  iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
 		copied = copy_to_iter(iomap->inline_data + pos, length, iter);
 	}
 	dio->size += copied;
-	return copied;
+	return copied ? copied : -EFAULT;
 }
 
 static loff_t