On Wed, Jun 1, 2016 at 9:48 PM, Christoph Hellwig [off-list ref] wrote:

On Mon, May 30, 2016 at 09:34:33PM +0800, Ming Lei wrote:

quoted

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index e71cfbd..e5d713b 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c

@@ -1157,9 +1157,7 @@ xfs_buf_ioapply_map(

 next_chunk:
      atomic_inc(&bp->b_io_remaining);
-     nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT);
-     if (nr_pages > total_nr_pages)
-             nr_pages = total_nr_pages;
+     nr_pages = min(total_nr_pages, BIO_MAX_PAGES);

      bio = bio_alloc(GFP_NOIO, nr_pages);

While I think this is a useful cleanup on it's own I think
you'd make everyones life easier if bio_alloc simply clamped down
the passed nr_pages value to the maximum allowed.

Yes, that looks a good cleanup, but need be careful because the
passed 'nr_pages' can be used after returning from bio_alloc() in
the current function, and it is easy to see this usage.

So we can do that in another patchset instead of this one.

Thanks,

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