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-   -   dm: factor max_io_len for code reuse (http://www.linux-archive.org/device-mapper-development/403434-dm-factor-max_io_len-code-reuse.html)

Mike Snitzer 07-23-2010 11:23 PM

dm: factor max_io_len for code reuse
 
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>
---
drivers/md/dm.c | 23 ++++++++++++++++-------
1 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a9a0625..8723572 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1022,11 +1022,20 @@ 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)
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti,
+ sector_t *offset_p)
{
sector_t offset = sector - ti->begin;
- sector_t len = ti->len - offset;
+ if (offset_p)
+ *offset_p = offset;
+
+ return ti->len - offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+{
+ sector_t offset;
+ sector_t len = max_io_len_target_boundary(sector, ti, &offset);

/*
* Does the target need to split even further ?
@@ -1244,7 +1253,7 @@ 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)
/*
@@ -1276,7 +1285,7 @@ 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) {
/*
@@ -1327,7 +1336,7 @@ 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);
@@ -1414,7 +1423,7 @@ 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)
--
1.6.6.1

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Mike Snitzer 07-24-2010 04:09 PM

dm: factor max_io_len for code reuse
 
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>
---
drivers/md/dm.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)

Index: linux-2.6-block/drivers/md/dm.c
================================================== =================
--- linux-2.6-block.orig/drivers/md/dm.c
+++ linux-2.6-block/drivers/md/dm.c
@@ -1029,11 +1029,20 @@ static void end_clone_request(struct req
dm_complete_request(clone, error);
}

-static sector_t max_io_len(struct mapped_device *md,
- sector_t sector, struct dm_target *ti)
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti,
+ sector_t *offset_p)
{
sector_t offset = sector - ti->begin;
- sector_t len = ti->len - offset;
+ if (offset_p)
+ *offset_p = offset;
+
+ return ti->len - offset;
+}
+
+static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+{
+ sector_t offset;
+ sector_t len = max_io_len_target_boundary(sector, ti, &offset);

/*
* Does the target need to split even further ?
@@ -1257,7 +1266,7 @@ static int __clone_and_map_discard(struc
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)
/*
@@ -1289,7 +1298,7 @@ static int __clone_and_map(struct clone_
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) {
/*
@@ -1340,7 +1349,7 @@ static int __clone_and_map(struct clone_
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);
@@ -1427,7 +1436,7 @@ static int dm_merge_bvec(struct request_
/*
* 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)

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Mike Snitzer 07-26-2010 09:36 PM

dm: factor max_io_len for code reuse
 
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>
---
drivers/md/dm.c | 22 ++++++++++++++--------
include/linux/device-mapper.h | 2 ++
2 files changed, 16 insertions(+), 8 deletions(-)

Index: linux-2.6-block/drivers/md/dm.c
================================================== =================
--- linux-2.6-block.orig/drivers/md/dm.c
+++ linux-2.6-block/drivers/md/dm.c
@@ -1029,17 +1029,23 @@ static void end_clone_request(struct req
dm_complete_request(clone, error);
}

-static sector_t max_io_len(struct mapped_device *md,
- sector_t sector, struct dm_target *ti)
+static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
{
- sector_t offset = sector - ti->begin;
- sector_t len = ti->len - offset;
+ 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 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)
@@ -1257,7 +1263,7 @@ static int __clone_and_map_discard(struc
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)
/*
@@ -1289,7 +1295,7 @@ static int __clone_and_map(struct clone_
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) {
/*
@@ -1340,7 +1346,7 @@ static int __clone_and_map(struct clone_
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);
@@ -1427,7 +1433,7 @@ static int dm_merge_bvec(struct request_
/*
* 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)
Index: linux-2.6-block/include/linux/device-mapper.h
================================================== =================
--- linux-2.6-block.orig/include/linux/device-mapper.h
+++ linux-2.6-block/include/linux/device-mapper.h
@@ -398,6 +398,8 @@ void *dm_vcalloc(unsigned long nmemb, un
#define dm_array_too_big(fixed, obj, num)
((num) > (UINT_MAX - (fixed)) / (obj))

+#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
+
static inline sector_t to_sector(unsigned long n)
{
return (n >> SECTOR_SHIFT);

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