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| author | Mike Snitzer <snitzer@redhat.com> | 2012-07-27 18:08:00 +0400 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2012-07-27 18:08:00 +0400 |
| commit | 542f90381422676544382d4071ba44a2de90a0c1 (patch) | |
| tree | 0eae6798ab2fdef68a0eb1ea5ac14f3cc3ffb740 /drivers/md/dm.c | |
| parent | 1df05483d758ea43abc375869fbe06be506ba827 (diff) | |
| download | linux-542f90381422676544382d4071ba44a2de90a0c1.tar.xz | |
dm: support non power of two target max_io_len
Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.
Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e24143cc2040..415c2803c0c9 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -968,22 +968,41 @@ static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti static sector_t max_io_len(sector_t sector, struct dm_target *ti) { sector_t len = max_io_len_target_boundary(sector, ti); + sector_t offset, max_len; /* - * Does the target need to split even further ? + * Does the target need to split even further? */ - if (ti->split_io) { - sector_t boundary; - sector_t offset = dm_target_offset(ti, sector); - boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) - - offset; - if (len > boundary) - len = boundary; + if (ti->max_io_len) { + offset = dm_target_offset(ti, sector); + if (unlikely(ti->max_io_len & (ti->max_io_len - 1))) + max_len = sector_div(offset, ti->max_io_len); + else + max_len = offset & (ti->max_io_len - 1); + max_len = ti->max_io_len - max_len; + + if (len > max_len) + len = max_len; } return len; } +int dm_set_target_max_io_len(struct dm_target *ti, sector_t len) +{ + if (len > UINT_MAX) { + DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)", + (unsigned long long)len, UINT_MAX); + ti->error = "Maximum size of target IO is too large"; + return -EINVAL; + } + + ti->max_io_len = (uint32_t) len; + + return 0; +} +EXPORT_SYMBOL_GPL(dm_set_target_max_io_len); + static void __map_bio(struct dm_target *ti, struct bio *clone, struct dm_target_io *tio) { |