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authorMike Snitzer <snitzer@redhat.com>2010-08-12 04:14:10 +0100
committerAlasdair G Kergon <agk@redhat.com>2010-08-12 04:14:10 +0100
commit56a67df766039666f61fb15b079f713e44a735ae (patch)
treecfeeb4f0a151b440293da593c723e9982368a58f
parent06a426cee9b35505aeb7516a67bd26496ca7ed08 (diff)
dm: factor out max_io_len_target_boundary
Split max_io_len_target_boundary out of max_io_len so that the discard support can make use of it without duplicating max_io_len code. Avoiding max_io_len's split_io logic enables DM's discard support to submit the entire discard request to a target. But discards must still be split on target boundaries. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm.c26
-rw-r--r--include/linux/device-mapper.h6
2 files changed, 24 insertions, 8 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3dd846e801fb..561313a7dac2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1030,17 +1030,27 @@ static void end_clone_request(struct request *clone, int error)
dm_complete_request(clone, error);
}
-static sector_t max_io_len(struct mapped_device *md,
- sector_t sector, struct dm_target *ti)
+/*
+ * Return maximum size of I/O possible at the supplied sector up to the current
+ * target boundary.
+ */
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
+{
+ sector_t target_offset = dm_target_offset(ti, sector);
+
+ return ti->len - target_offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
{
- sector_t offset = sector - ti->begin;
- sector_t len = ti->len - offset;
+ sector_t len = max_io_len_target_boundary(sector, ti);
/*
* 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)
@@ -1258,7 +1268,7 @@ static int __clone_and_map_discard(struct clone_info *ci)
if (!ti->num_discard_requests)
return -EOPNOTSUPP;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
if (ci->sector_count > max)
/*
@@ -1290,7 +1300,7 @@ static int __clone_and_map(struct clone_info *ci)
if (!dm_target_is_valid(ti))
return -EIO;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
if (ci->sector_count <= max) {
/*
@@ -1341,7 +1351,7 @@ static int __clone_and_map(struct clone_info *ci)
if (!dm_target_is_valid(ti))
return -EIO;
- max = max_io_len(ci->md, ci->sector, ti);
+ max = max_io_len(ci->sector, ti);
}
len = min(remaining, max);
@@ -1428,7 +1438,7 @@ static int dm_merge_bvec(struct request_queue *q,
/*
* Find maximum amount of I/O that won't need splitting
*/
- max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
+ max_sectors = min(max_io_len(bvm->bi_sector, ti),
(sector_t) BIO_MAX_SECTORS);
max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
if (max_size < 0)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 751ce21dea7b..2970022faa63 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -398,6 +398,12 @@ void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
#define dm_array_too_big(fixed, obj, num) \
((num) > (UINT_MAX - (fixed)) / (obj))
+/*
+ * Sector offset taken relative to the start of the target instead of
+ * relative to the start of the device.
+ */
+#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
+
static inline sector_t to_sector(unsigned long n)
{
return (n >> SECTOR_SHIFT);