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Commit 2ec3182f authored by Dongsu Park's avatar Dongsu Park Committed by Jens Axboe
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Documentation: update notes in biovecs about arbitrarily sized bios 



Update block/biovecs.txt so that it includes a note on what kind of
effects arbitrarily sized bios would bring to the block layer.
Also fix a trivial typo, bio_iter_iovec.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: default avatarDongsu Park <dpark@posteo.net>
Signed-off-by: default avatarMing Lin <ming.l@ssi.samsung.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent b54ffb73

Documentation/block/biovecs.txt

+9 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ particular, presenting the illusion of partially completed biovecs so that 
normal code doesn't have to deal with bi_bvec_done.



 * Driver code should no longer refer to biovecs directly; we now have

   bio_iovec() and bio_iovec_iter() macros that return literal struct biovecs,

   bio_iovec() and bio_iter_iovec() macros that return literal struct biovecs,

   constructed from the raw biovecs but taking into account bi_bvec_done and

   bi_size.
@@ -109,3 +109,11 @@ Other implications: 
   over all the biovecs in the new bio - which is silly as it's not needed.



   So, don't use bi_vcnt anymore.



 * The current interface allows the block layer to split bios as needed, so we

   could eliminate a lot of complexity particularly in stacked drivers. Code

   that creates bios can then create whatever size bios are convenient, and

   more importantly stacked drivers don't have to deal with both their own bio

   size limitations and the limitations of the underlying devices. Thus

   there's no need to define ->merge_bvec_fn() callbacks for individual block

   drivers.