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Diffstat (limited to 'Documentation/block/biovecs.txt')
| -rw-r--r-- | Documentation/block/biovecs.txt | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt index 74a32ad52f53..25689584e6e0 100644 --- a/Documentation/block/biovecs.txt +++ b/Documentation/block/biovecs.txt @@ -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. |