[PATCH] dm: extract device limit setting

Separate the setting of device I/O limits from dm_get_device().  dm-loop will
use this.

Signed-off-by: Bryn Reeves <breeves@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 47412ae..4920998 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -522,56 +522,61 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
        return 0;
 }
 
-
-int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
-                 sector_t len, int mode, struct dm_dev **result)
+void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
 {
-       int r = __table_get_device(ti->table, ti, path,
-                                  start, len, mode, result);
-       if (!r) {
-               request_queue_t *q = bdev_get_queue((*result)->bdev);
-               struct io_restrictions *rs = &ti->limits;
-
-               /*
-                * Combine the device limits low.
-                *
-                * FIXME: if we move an io_restriction struct
-                *        into q this would just be a call to
-                *        combine_restrictions_low()
-                */
+       request_queue_t *q = bdev_get_queue(bdev);
+       struct io_restrictions *rs = &ti->limits;
+
+       /*
+        * Combine the device limits low.
+        *
+        * FIXME: if we move an io_restriction struct
+        *        into q this would just be a call to
+        *        combine_restrictions_low()
+        */
+       rs->max_sectors =
+               min_not_zero(rs->max_sectors, q->max_sectors);
+
+       /* FIXME: Device-Mapper on top of RAID-0 breaks because DM
+        *        currently doesn't honor MD's merge_bvec_fn routine.
+        *        In this case, we'll force DM to use PAGE_SIZE or
+        *        smaller I/O, just to be safe. A better fix is in the
+        *        works, but add this for the time being so it will at
+        *        least operate correctly.
+        */
+       if (q->merge_bvec_fn)
                rs->max_sectors =
-                       min_not_zero(rs->max_sectors, q->max_sectors);
+                       min_not_zero(rs->max_sectors,
+                                    (unsigned int) (PAGE_SIZE >> 9));
 
-               /* FIXME: Device-Mapper on top of RAID-0 breaks because DM
-                *        currently doesn't honor MD's merge_bvec_fn routine.
-                *        In this case, we'll force DM to use PAGE_SIZE or
-                *        smaller I/O, just to be safe. A better fix is in the
-                *        works, but add this for the time being so it will at
-                *        least operate correctly.
-                */
-               if (q->merge_bvec_fn)
-                       rs->max_sectors =
-                               min_not_zero(rs->max_sectors,
-                                            (unsigned int) (PAGE_SIZE >> 9));
+       rs->max_phys_segments =
+               min_not_zero(rs->max_phys_segments,
+                            q->max_phys_segments);
 
-               rs->max_phys_segments =
-                       min_not_zero(rs->max_phys_segments,
-                                    q->max_phys_segments);
+       rs->max_hw_segments =
+               min_not_zero(rs->max_hw_segments, q->max_hw_segments);
 
-               rs->max_hw_segments =
-                       min_not_zero(rs->max_hw_segments, q->max_hw_segments);
+       rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
 
-               rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
+       rs->max_segment_size =
+               min_not_zero(rs->max_segment_size, q->max_segment_size);
 
-               rs->max_segment_size =
-                       min_not_zero(rs->max_segment_size, q->max_segment_size);
+       rs->seg_boundary_mask =
+               min_not_zero(rs->seg_boundary_mask,
+                            q->seg_boundary_mask);
 
-               rs->seg_boundary_mask =
-                       min_not_zero(rs->seg_boundary_mask,
-                                    q->seg_boundary_mask);
+       rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
+}
+EXPORT_SYMBOL_GPL(dm_set_device_limits);
 
-               rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
-       }
+int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
+                 sector_t len, int mode, struct dm_dev **result)
+{
+       int r = __table_get_device(ti->table, ti, path,
+                                  start, len, mode, result);
+
+       if (!r)
+               dm_set_device_limits(ti, (*result)->bdev);
 
        return r;
 }

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 8cbc46b..7a48d42 100644 (file)
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -71,6 +71,11 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
 
 void dm_error(const char *message);
 
+/*
+ * Combine device limits.
+ */
+void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
+
 /*
  * Constructors should call these functions to ensure destination devices
  * are opened/closed correctly.