From 542f90381422676544382d4071ba44a2de90a0c1 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Fri, 27 Jul 2012 15:08:00 +0100 Subject: [PATCH] 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 Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid.c | 11 +++++------ drivers/md/dm-raid1.c | 6 +++++- drivers/md/dm-snap.c | 27 +++++++++++++++------------ drivers/md/dm-stripe.c | 5 ++++- drivers/md/dm-thin.c | 5 ++++- drivers/md/dm.c | 35 +++++++++++++++++++++++++++-------- include/linux/device-mapper.h | 9 +++++++-- include/linux/dm-ioctl.h | 4 ++-- 8 files changed, 69 insertions(+), 33 deletions(-) diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 017c34d78d6..858a8b70811 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -353,6 +353,7 @@ static int parse_raid_params(struct raid_set *rs, char **argv, { unsigned i, rebuild_cnt = 0; unsigned long value, region_size = 0; + sector_t max_io_len; char *key; /* @@ -522,14 +523,12 @@ static int parse_raid_params(struct raid_set *rs, char **argv, return -EINVAL; if (rs->md.chunk_sectors) - rs->ti->split_io = rs->md.chunk_sectors; + max_io_len = rs->md.chunk_sectors; else - rs->ti->split_io = region_size; + max_io_len = region_size; - if (rs->md.chunk_sectors) - rs->ti->split_io = rs->md.chunk_sectors; - else - rs->ti->split_io = region_size; + if (dm_set_target_max_io_len(rs->ti, max_io_len)) + return -EINVAL; /* Assume there are no metadata devices until the drives are parsed */ rs->md.persistent = 0; diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index b58b7a33914..819ccba6591 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -1081,7 +1081,11 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) } ti->private = ms; - ti->split_io = dm_rh_get_region_size(ms->rh); + + r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh)); + if (r) + goto err_free_context; + ti->num_flush_requests = 1; ti->num_discard_requests = 1; ti->discard_zeroes_data_unsupported = 1; diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index a228c20e40b..6c0f3e33923 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -691,7 +691,7 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new) * Return a minimum chunk size of all snapshots that have the specified origin. * Return zero if the origin has no snapshots. */ -static sector_t __minimum_chunk_size(struct origin *o) +static uint32_t __minimum_chunk_size(struct origin *o) { struct dm_snapshot *snap; unsigned chunk_size = 0; @@ -701,7 +701,7 @@ static sector_t __minimum_chunk_size(struct origin *o) chunk_size = min_not_zero(chunk_size, snap->store->chunk_size); - return chunk_size; + return (uint32_t) chunk_size; } /* @@ -1172,7 +1172,10 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->error = "Chunk size not set"; goto bad_read_metadata; } - ti->split_io = s->store->chunk_size; + + r = dm_set_target_max_io_len(ti, s->store->chunk_size); + if (r) + goto bad_read_metadata; return 0; @@ -1239,7 +1242,7 @@ static void __handover_exceptions(struct dm_snapshot *snap_src, snap_dest->store->snap = snap_dest; snap_src->store->snap = snap_src; - snap_dest->ti->split_io = snap_dest->store->chunk_size; + snap_dest->ti->max_io_len = snap_dest->store->chunk_size; snap_dest->valid = snap_src->valid; /* @@ -1817,9 +1820,9 @@ static void snapshot_resume(struct dm_target *ti) up_write(&s->lock); } -static sector_t get_origin_minimum_chunksize(struct block_device *bdev) +static uint32_t get_origin_minimum_chunksize(struct block_device *bdev) { - sector_t min_chunksize; + uint32_t min_chunksize; down_read(&_origins_lock); min_chunksize = __minimum_chunk_size(__lookup_origin(bdev)); @@ -1838,9 +1841,9 @@ static void snapshot_merge_resume(struct dm_target *ti) snapshot_resume(ti); /* - * snapshot-merge acts as an origin, so set ti->split_io + * snapshot-merge acts as an origin, so set ti->max_io_len */ - ti->split_io = get_origin_minimum_chunksize(s->origin->bdev); + ti->max_io_len = get_origin_minimum_chunksize(s->origin->bdev); start_merge(s); } @@ -2073,12 +2076,12 @@ static int origin_write_extent(struct dm_snapshot *merging_snap, struct origin *o; /* - * The origin's __minimum_chunk_size() got stored in split_io + * The origin's __minimum_chunk_size() got stored in max_io_len * by snapshot_merge_resume(). */ down_read(&_origins_lock); o = __lookup_origin(merging_snap->origin->bdev); - for (n = 0; n < size; n += merging_snap->ti->split_io) + for (n = 0; n < size; n += merging_snap->ti->max_io_len) if (__origin_write(&o->snapshots, sector + n, NULL) == DM_MAPIO_SUBMITTED) must_wait = 1; @@ -2138,14 +2141,14 @@ static int origin_map(struct dm_target *ti, struct bio *bio, } /* - * Set the target "split_io" field to the minimum of all the snapshots' + * Set the target "max_io_len" field to the minimum of all the snapshots' * chunk sizes. */ static void origin_resume(struct dm_target *ti) { struct dm_dev *dev = ti->private; - ti->split_io = get_origin_minimum_chunksize(dev->bdev); + ti->max_io_len = get_origin_minimum_chunksize(dev->bdev); } static int origin_status(struct dm_target *ti, status_type_t type, char *result, diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index 6931bd18b61..992c9d4c3bd 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -165,7 +165,10 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) else sc->stripes_shift = __ffs(stripes); - ti->split_io = chunk_size; + r = dm_set_target_max_io_len(ti, chunk_size); + if (r) + return r; + ti->num_flush_requests = stripes; ti->num_discard_requests = stripes; diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index e89f8e7d8a3..350bcf40485 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2628,7 +2628,10 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) goto bad_thin_open; } - ti->split_io = tc->pool->sectors_per_block; + r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); + if (r) + goto bad_thin_open; + ti->num_flush_requests = 1; /* In case the pool supports discards, pass them on. */ diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e24143cc204..415c2803c0c 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) { diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index d70cbb2ada2..b19c1e189a6 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -186,8 +186,8 @@ struct dm_target { sector_t begin; sector_t len; - /* Always a power of 2 */ - sector_t split_io; + /* If non-zero, maximum size of I/O submitted to a target. */ + uint32_t max_io_len; /* * A number of zero-length barrier requests that will be submitted @@ -357,6 +357,11 @@ void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callback */ int dm_table_complete(struct dm_table *t); +/* + * Target may require that it is never sent I/O larger than len. + */ +int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len); + /* * Table reference counting. */ diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h index 75fd5573516..3ece4eee84c 100644 --- a/include/linux/dm-ioctl.h +++ b/include/linux/dm-ioctl.h @@ -268,8 +268,8 @@ enum { #define DM_VERSION_MAJOR 4 #define DM_VERSION_MINOR 22 -#define DM_VERSION_PATCHLEVEL 0 -#define DM_VERSION_EXTRA "-ioctl (2011-10-19)" +#define DM_VERSION_PATCHLEVEL 1 +#define DM_VERSION_EXTRA "-ioctl (2012-06-01)" /* Status bits */ #define DM_READONLY_FLAG (1 << 0) /* In/Out */