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| author | Kent Overstreet <koverstreet@google.com> | 2013-02-06 12:23:11 -0800 |
|---|---|---|
| committer | Kent Overstreet <koverstreet@google.com> | 2013-03-23 14:26:28 -0700 |
| commit | d74c6d514fe314b8bdab58b487b25992291577ec (patch) | |
| tree | 2e04cd492235dc7982bae1ba7ef83f276800c319 /include/linux/bio.h | |
| parent | 6bc454d150047fcfbf53346412e64cdf3bf61a79 (diff) | |
| download | lwn-d74c6d514fe314b8bdab58b487b25992291577ec.tar.gz lwn-d74c6d514fe314b8bdab58b487b25992291577ec.zip | |
block: Add bio_for_each_segment_all()
__bio_for_each_segment() iterates bvecs from the specified index
instead of bio->bv_idx. Currently, the only usage is to walk all the
bvecs after the bio has been advanced by specifying 0 index.
For immutable bvecs, we need to split these apart;
bio_for_each_segment() is going to have a different implementation.
This will also help document the intent of code that's using it -
bio_for_each_segment_all() is only legal to use for code that owns the
bio.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Neil Brown <neilb@suse.de>
CC: Boaz Harrosh <bharrosh@panasas.com>
Diffstat (limited to 'include/linux/bio.h')
| -rw-r--r-- | include/linux/bio.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h index 90d36c65cb70..be2efa09f9bf 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -137,16 +137,27 @@ static inline int bio_has_allocated_vec(struct bio *bio) #define bio_io_error(bio) bio_endio((bio), -EIO) /* - * drivers should not use the __ version unless they _really_ want to - * run through the entire bio and not just pending pieces + * drivers should not use the __ version unless they _really_ know what + * they're doing */ #define __bio_for_each_segment(bvl, bio, i, start_idx) \ for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \ i < (bio)->bi_vcnt; \ bvl++, i++) +/* + * drivers should _never_ use the all version - the bio may have been split + * before it got to the driver and the driver won't own all of it + */ +#define bio_for_each_segment_all(bvl, bio, i) \ + for (i = 0; \ + bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt; \ + i++) + #define bio_for_each_segment(bvl, bio, i) \ - __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx) + for (i = (bio)->bi_idx; \ + bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt; \ + i++) /* * get a reference to a bio, so it won't disappear. the intended use is |