3 files changed, 115 insertions, 87 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 267817edc844..09a57113955e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -62,12 +62,6 @@ struct dm_table {
         /* a list of devices used by this table */
         struct list_head devices;
 
-        /*
-         * These are optimistic limits taken from all the
-         * targets, some targets will need smaller limits.
-         */
-        struct queue_limits limits;
-
         /* events get handed up using this callback */
         void (*event_fn)(void *);
         void *event_context;
@@ -346,18 +340,21 @@ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
 /*
  * If possible, this checks an area of a destination device is valid.
  */
-static int device_area_is_valid(struct dm_target *ti, struct block_device *bdev,
-                             sector_t start, sector_t len)
+static int device_area_is_valid(struct dm_target *ti, struct dm_dev *dev,
+                                sector_t start, void *data)
 {
-        sector_t dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+        struct queue_limits *limits = data;
+        struct block_device *bdev = dev->bdev;
+        sector_t dev_size =
+                i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
         unsigned short logical_block_size_sectors =
-                ti->limits.logical_block_size >> SECTOR_SHIFT;
+                limits->logical_block_size >> SECTOR_SHIFT;
         char b[BDEVNAME_SIZE];
 
         if (!dev_size)
                 return 1;
 
-        if ((start >= dev_size) || (start + len > dev_size)) {
+        if ((start >= dev_size) || (start + ti->len > dev_size)) {
                 DMWARN("%s: %s too small for target",
                        dm_device_name(ti->table->md), bdevname(bdev, b));
                 return 0;
@@ -371,16 +368,16 @@ static int device_area_is_valid(struct dm_target *ti, struct block_device *bdev,
                        "logical block size %hu of %s",
                        dm_device_name(ti->table->md),
                        (unsigned long long)start,
-                       ti->limits.logical_block_size, bdevname(bdev, b));
+                       limits->logical_block_size, bdevname(bdev, b));
                 return 0;
         }
 
-        if (len & (logical_block_size_sectors - 1)) {
+        if (ti->len & (logical_block_size_sectors - 1)) {
                 DMWARN("%s: len=%llu not aligned to h/w "
                        "logical block size %hu of %s",
                        dm_device_name(ti->table->md),
-                       (unsigned long long)len,
-                       ti->limits.logical_block_size, bdevname(bdev, b));
+                       (unsigned long long)ti->len,
+                       limits->logical_block_size, bdevname(bdev, b));
                 return 0;
         }
 
@@ -479,18 +476,21 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
  */
 #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)
+int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
+                         sector_t start, void *data)
 {
+        struct queue_limits *limits = data;
+        struct block_device *bdev = dev->bdev;
         struct request_queue *q = bdev_get_queue(bdev);
         char b[BDEVNAME_SIZE];
 
         if (unlikely(!q)) {
                 DMWARN("%s: Cannot set limits for nonexistent device %s",
                        dm_device_name(ti->table->md), bdevname(bdev, b));
-                return;
+                return 0;
         }
 
-        if (blk_stack_limits(&ti->limits, &q->limits, 0) < 0)
+        if (blk_stack_limits(limits, &q->limits, start) < 0)
                 DMWARN("%s: target device %s is misaligned",
                        dm_device_name(ti->table->md), bdevname(bdev, b));
 
@@ -501,32 +501,21 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
          */
 
         if (q->merge_bvec_fn && !ti->type->merge)
-                ti->limits.max_sectors =
-                        min_not_zero(ti->limits.max_sectors,
+                limits->max_sectors =
+                        min_not_zero(limits->max_sectors,
                                      (unsigned int) (PAGE_SIZE >> 9));
+        return 0;
 }
 EXPORT_SYMBOL_GPL(dm_set_device_limits);
 
 int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
                   sector_t len, fmode_t mode, struct dm_dev **result)
 {
-        int r = __table_get_device(ti->table, ti, path,
-                                   start, len, mode, result);
-
-        if (r)
-                return r;
-
-        dm_set_device_limits(ti, (*result)->bdev);
-
-        if (!device_area_is_valid(ti, (*result)->bdev, start, len)) {
-                dm_put_device(ti, *result);
-                *result = NULL;
-                return -EINVAL;
-        }
-
-        return r;
+        return __table_get_device(ti->table, ti, path,
+                                  start, len, mode, result);
 }
 
+
 /*
  * Decrement a devices use count and remove it if necessary.
  */
@@ -641,34 +630,6 @@ int dm_split_args(int *argc, char ***argvp, char *input)
         return 0;
 }
 
-static void init_valid_queue_limits(struct queue_limits *limits)
-{
-        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().
-         */
-}
-
 /*
  * Impose necessary and sufficient conditions on a devices's table such
  * that any incoming bio which respects its logical_block_size can be
@@ -676,14 +637,15 @@ static void init_valid_queue_limits(struct queue_limits *limits)
  * two or more targets, the size of each piece it gets split into must
  * be compatible with the logical_block_size of the target processing it.
  */
-static int validate_hardware_logical_block_alignment(struct dm_table *table)
+static int validate_hardware_logical_block_alignment(struct dm_table *table,
+                                                 struct queue_limits *limits)
 {
         /*
          * This function uses arithmetic modulo the logical_block_size
          * (in units of 512-byte sectors).
          */
         unsigned short device_logical_block_size_sects =
-                table->limits.logical_block_size >> SECTOR_SHIFT;
+                limits->logical_block_size >> SECTOR_SHIFT;
 
         /*
          * Offset of the start of the next table entry, mod logical_block_size.
@@ -697,6 +659,7 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table)
         unsigned short remaining = 0;
 
         struct dm_target *uninitialized_var(ti);
+        struct queue_limits ti_limits;
         unsigned i = 0;
 
         /*
@@ -705,12 +668,19 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table)
         while (i < dm_table_get_num_targets(table)) {
                 ti = dm_table_get_target(table, i++);
 
+                blk_set_default_limits(&ti_limits);
+
+                /* combine all target devices' limits */
+                if (ti->type->iterate_devices)
+                        ti->type->iterate_devices(ti, dm_set_device_limits,
+                                                  &ti_limits);
+
                 /*
                  * If the remaining sectors fall entirely within this
                  * table entry are they compatible with its logical_block_size?
                  */
                 if (remaining < ti->len &&
-                    remaining & ((ti->limits.logical_block_size >>
+                    remaining & ((ti_limits.logical_block_size >>
                                   SECTOR_SHIFT) - 1))
                         break;  /* Error */
 
@@ -723,11 +693,11 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table)
 
         if (remaining) {
                 DMWARN("%s: table line %u (start sect %llu len %llu) "
-                       "not aligned to hardware logical block size %hu",
+                       "not aligned to h/w logical block size %hu",
                        dm_device_name(table->md), i,
                        (unsigned long long) ti->begin,
                        (unsigned long long) ti->len,
-                       table->limits.logical_block_size);
+                       limits->logical_block_size);
                 return -EINVAL;
         }
 
@@ -786,12 +756,6 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 
         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 
-        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:
@@ -834,12 +798,6 @@ int dm_table_complete(struct dm_table *t)
         int r = 0;
         unsigned int leaf_nodes;
 
-        init_valid_queue_limits(&t->limits);
-
-        r = validate_hardware_logical_block_alignment(t);
-        if (r)
-                return r;
-
         /* how many indexes will the btree have ? */
         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
@@ -915,6 +873,57 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
 }
 
 /*
+ * Establish the new table's queue_limits and validate them.
+ */
+int dm_calculate_queue_limits(struct dm_table *table,
+                              struct queue_limits *limits)
+{
+        struct dm_target *uninitialized_var(ti);
+        struct queue_limits ti_limits;
+        unsigned i = 0;
+
+        blk_set_default_limits(limits);
+
+        while (i < dm_table_get_num_targets(table)) {
+                blk_set_default_limits(&ti_limits);
+
+                ti = dm_table_get_target(table, i++);
+
+                if (!ti->type->iterate_devices)
+                        goto combine_limits;
+
+                /*
+                 * Combine queue limits of all the devices this target uses.
+                 */
+                ti->type->iterate_devices(ti, dm_set_device_limits,
+                                          &ti_limits);
+
+                /*
+                 * Check each device area is consistent with the target's
+                 * overall queue limits.
+                 */
+                if (!ti->type->iterate_devices(ti, device_area_is_valid,
+                                               &ti_limits))
+                        return -EINVAL;
+
+combine_limits:
+                /*
+                 * Merge this target's queue limits into the overall limits
+                 * for the table.
+                 */
+                if (blk_stack_limits(limits, &ti_limits, 0) < 0)
+                        DMWARN("%s: target device "
+                               "(start sect %llu len %llu) "
+                               "is misaligned",
+                               dm_device_name(table->md),
+                               (unsigned long long) ti->begin,
+                               (unsigned long long) ti->len);
+        }
+
+        return validate_hardware_logical_block_alignment(table, limits);
+}
+
+/*
  * Set the integrity profile for this device if all devices used have
  * matching profiles.
  */
@@ -953,14 +962,24 @@ no_integrity:
         return;
 }
 
-void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
+void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+                               struct queue_limits *limits)
 {
         /*
+         * Each target device in the table has a data area that should normally
+         * be aligned such that the DM device's alignment_offset is 0.
+         * FIXME: Propagate alignment_offsets up the stack and warn of
+         *        sub-optimal or inconsistent settings.
+         */
+        limits->alignment_offset = 0;
+        limits->misaligned = 0;
+
+        /*
          * Copy table's limits to the DM device's request_queue
          */
-        q->limits = t->limits;
+        q->limits = *limits;
 
-        if (t->limits.no_cluster)
+        if (limits->no_cluster)
                 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
         else
                 queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a9210bb594e7..f609793a92d0 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1313,7 +1313,8 @@ static void __set_size(struct mapped_device *md, sector_t size)
         mutex_unlock(&md->bdev->bd_inode->i_mutex);
 }
 
-static int __bind(struct mapped_device *md, struct dm_table *t)
+static int __bind(struct mapped_device *md, struct dm_table *t,
+                  struct queue_limits *limits)
 {
         struct request_queue *q = md->queue;
         sector_t size;
@@ -1337,7 +1338,7 @@ static int __bind(struct mapped_device *md, struct dm_table *t)
 
         write_lock(&md->map_lock);
         md->map = t;
-        dm_table_set_restrictions(t, q);
+        dm_table_set_restrictions(t, q, limits);
         write_unlock(&md->map_lock);
 
         return 0;
@@ -1562,6 +1563,7 @@ static void dm_queue_flush(struct mapped_device *md)
  */
 int dm_swap_table(struct mapped_device *md, struct dm_table *table)
 {
+        struct queue_limits limits;
         int r = -EINVAL;
 
         mutex_lock(&md->suspend_lock);
@@ -1570,8 +1572,12 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
         if (!dm_suspended(md))
                 goto out;
 
+        r = dm_calculate_queue_limits(table, &limits);
+        if (r)
+                goto out;
+
         __unbind(md);
-        r = __bind(md, table);
+        r = __bind(md, table, &limits);
 
 out:
         mutex_unlock(&md->suspend_lock);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index b5935c610c44..604e85caadf6 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -41,7 +41,10 @@ void dm_table_event_callback(struct dm_table *t,
                              void (*fn)(void *), void *context);
 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
-void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
+int dm_calculate_queue_limits(struct dm_table *table,
+                              struct queue_limits *limits);
+void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+                               struct queue_limits *limits);
 struct list_head *dm_table_get_devices(struct dm_table *t);
 void dm_table_presuspend_targets(struct dm_table *t);
 void dm_table_postsuspend_targets(struct dm_table *t);