dm table: replace struct io_restrictions with struct queue_limits

Use blk_stack_limits() to stack block limits (including topology) rather
than duplicate the equivalent within Device Mapper.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

2 files changed, 45 insertions, 109 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index e3bcfb8b15a1..41ec2bf9fbe9 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -66,7 +66,7 @@ struct dm_table {
          * These are optimistic limits taken from all the
          * targets, some targets will need smaller limits.
          */
-        struct io_restrictions limits;
+        struct queue_limits limits;
 
         /* events get handed up using this callback */
         void (*event_fn)(void *);
@@ -89,43 +89,6 @@ static unsigned int int_log(unsigned int n, unsigned int base)
 }
 
 /*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
-/*
- * Combine two io_restrictions, always taking the lower value.
- */
-static void combine_restrictions_low(struct io_restrictions *lhs,
-                                     struct io_restrictions *rhs)
-{
-        lhs->max_sectors =
-                min_not_zero(lhs->max_sectors, rhs->max_sectors);
-
-        lhs->max_phys_segments =
-                min_not_zero(lhs->max_phys_segments, rhs->max_phys_segments);
-
-        lhs->max_hw_segments =
-                min_not_zero(lhs->max_hw_segments, rhs->max_hw_segments);
-
-        lhs->logical_block_size = max(lhs->logical_block_size,
-                                      rhs->logical_block_size);
-
-        lhs->max_segment_size =
-                min_not_zero(lhs->max_segment_size, rhs->max_segment_size);
-
-        lhs->max_hw_sectors =
-                min_not_zero(lhs->max_hw_sectors, rhs->max_hw_sectors);
-
-        lhs->seg_boundary_mask =
-                min_not_zero(lhs->seg_boundary_mask, rhs->seg_boundary_mask);
-
-        lhs->bounce_pfn = min_not_zero(lhs->bounce_pfn, rhs->bounce_pfn);
-
-        lhs->no_cluster |= rhs->no_cluster;
-}
-
-/*
  * Calculate the index of the child node of the n'th node k'th key.
  */
 static inline unsigned int get_child(unsigned int n, unsigned int k)
@@ -511,10 +474,14 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
         return 0;
 }
 
+/*
+ * Returns the minimum that is _not_ zero, unless both are zero.
+ */
+#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
+
 void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
 {
         struct request_queue *q = bdev_get_queue(bdev);
-        struct io_restrictions *rs = &ti->limits;
         char b[BDEVNAME_SIZE];
 
         if (unlikely(!q)) {
@@ -523,15 +490,9 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
                 return;
         }
 
-        /*
-         * 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, queue_max_sectors(q));
+        if (blk_stack_limits(&ti->limits, &q->limits, 0) < 0)
+                DMWARN("%s: target device %s is misaligned",
+                       dm_device_name(ti->table->md), bdevname(bdev, b));
 
         /*
          * Check if merge fn is supported.
@@ -540,33 +501,9 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
          */
 
         if (q->merge_bvec_fn && !ti->type->merge)
-                rs->max_sectors =
-                        min_not_zero(rs->max_sectors,
+                ti->limits.max_sectors =
+                        min_not_zero(ti->limits.max_sectors,
                                      (unsigned int) (PAGE_SIZE >> 9));
-
-        rs->max_phys_segments =
-                min_not_zero(rs->max_phys_segments,
-                             queue_max_phys_segments(q));
-
-        rs->max_hw_segments =
-                min_not_zero(rs->max_hw_segments, queue_max_hw_segments(q));
-
-        rs->logical_block_size = max(rs->logical_block_size,
-                                     queue_logical_block_size(q));
-
-        rs->max_segment_size =
-                min_not_zero(rs->max_segment_size, queue_max_segment_size(q));
-
-        rs->max_hw_sectors =
-                min_not_zero(rs->max_hw_sectors, queue_max_hw_sectors(q));
-
-        rs->seg_boundary_mask =
-                min_not_zero(rs->seg_boundary_mask,
-                             queue_segment_boundary(q));
-
-        rs->bounce_pfn = min_not_zero(rs->bounce_pfn, queue_bounce_pfn(q));
-
-        rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
 }
 EXPORT_SYMBOL_GPL(dm_set_device_limits);
 
@@ -704,24 +641,32 @@ int dm_split_args(int *argc, char ***argvp, char *input)
         return 0;
 }
 
-static void check_for_valid_limits(struct io_restrictions *rs)
+static void init_valid_queue_limits(struct queue_limits *limits)
 {
-        if (!rs->max_sectors)
-                rs->max_sectors = SAFE_MAX_SECTORS;
-        if (!rs->max_hw_sectors)
-                rs->max_hw_sectors = SAFE_MAX_SECTORS;
-        if (!rs->max_phys_segments)
-                rs->max_phys_segments = MAX_PHYS_SEGMENTS;
-        if (!rs->max_hw_segments)
-                rs->max_hw_segments = MAX_HW_SEGMENTS;
-        if (!rs->logical_block_size)
-                rs->logical_block_size = 1 << SECTOR_SHIFT;
-        if (!rs->max_segment_size)
-                rs->max_segment_size = MAX_SEGMENT_SIZE;
-        if (!rs->seg_boundary_mask)
-                rs->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
-        if (!rs->bounce_pfn)
-                rs->bounce_pfn = -1;
+        if (!limits->max_sectors)
+                limits->max_sectors = SAFE_MAX_SECTORS;
+        if (!limits->max_hw_sectors)
+                limits->max_hw_sectors = SAFE_MAX_SECTORS;
+        if (!limits->max_phys_segments)
+                limits->max_phys_segments = MAX_PHYS_SEGMENTS;
+        if (!limits->max_hw_segments)
+                limits->max_hw_segments = MAX_HW_SEGMENTS;
+        if (!limits->logical_block_size)
+                limits->logical_block_size = 1 << SECTOR_SHIFT;
+        if (!limits->physical_block_size)
+                limits->physical_block_size = 1 << SECTOR_SHIFT;
+        if (!limits->io_min)
+                limits->io_min = 1 << SECTOR_SHIFT;
+        if (!limits->max_segment_size)
+                limits->max_segment_size = MAX_SEGMENT_SIZE;
+        if (!limits->seg_boundary_mask)
+                limits->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
+        if (!limits->bounce_pfn)
+                limits->bounce_pfn = -1;
+        /*
+         * The other fields (alignment_offset, io_opt, misaligned)
+         * hold 0 from the kzalloc().
+         */
 }
 
 /*
@@ -841,9 +786,12 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 
         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 
-        /* FIXME: the plan is to combine high here and then have
-         * the merge fn apply the target level restrictions. */
-        combine_restrictions_low(&t->limits, &tgt->limits);
+        if (blk_stack_limits(&t->limits, &tgt->limits, 0) < 0)
+                DMWARN("%s: target device (start sect %llu len %llu) "
+                       "is misaligned",
+                       dm_device_name(t->md),
+                       (unsigned long long) tgt->begin,
+                       (unsigned long long) tgt->len);
         return 0;
 
  bad:
@@ -886,7 +834,7 @@ int dm_table_complete(struct dm_table *t)
         int r = 0;
         unsigned int leaf_nodes;
 
-        check_for_valid_limits(&t->limits);
+        init_valid_queue_limits(&t->limits);
 
         r = validate_hardware_logical_block_alignment(t);
         if (r)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index fc36a4d07723..236880c1dc3f 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -144,18 +144,6 @@ struct target_type {
         struct list_head list;
 };
 
-struct io_restrictions {
-        unsigned long bounce_pfn;
-        unsigned long seg_boundary_mask;
-        unsigned max_hw_sectors;
-        unsigned max_sectors;
-        unsigned max_segment_size;
-        unsigned short logical_block_size;
-        unsigned short max_hw_segments;
-        unsigned short max_phys_segments;
-        unsigned char no_cluster; /* inverted so that 0 is default */
-};
-
 struct dm_target {
         struct dm_table *table;
         struct target_type *type;
@@ -164,7 +152,7 @@ struct dm_target {
         sector_t begin;
         sector_t len;
 
-        /* FIXME: turn this into a mask, and merge with io_restrictions */
+        /* FIXME: turn this into a mask, and merge with queue_limits */
         /* Always a power of 2 */
         sector_t split_io;
 
@@ -182,7 +170,7 @@ struct dm_target {
          * These are automatically filled in by
          * dm_table_get_device.
          */
-        struct io_restrictions limits;
+        struct queue_limits limits;
 
         /* target specific data */
         void *private;