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-rw-r--r--block/blk-settings.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 1989a177be20..865fe4ebbf9b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -892,6 +892,31 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
EXPORT_SYMBOL(blk_stack_limits);
/**
+ * queue_limits_stack_bdev - adjust queue_limits for stacked devices
+ * @t: the stacking driver limits (top device)
+ * @bdev: the underlying block device (bottom)
+ * @offset: offset to beginning of data within component device
+ * @pfx: prefix to use for warnings logged
+ *
+ * Description:
+ * This function is used by stacking drivers like MD and DM to ensure
+ * that all component devices have compatible block sizes and
+ * alignments. The stacking driver must provide a queue_limits
+ * struct (top) and then iteratively call the stacking function for
+ * all component (bottom) devices. The stacking function will
+ * attempt to combine the values and ensure proper alignment.
+ */
+void queue_limits_stack_bdev(struct queue_limits *t, struct block_device *bdev,
+ sector_t offset, const char *pfx)
+{
+ if (blk_stack_limits(t, &bdev_get_queue(bdev)->limits,
+ get_start_sect(bdev) + offset))
+ pr_notice("%s: Warning: Device %pg is misaligned\n",
+ pfx, bdev);
+}
+EXPORT_SYMBOL_GPL(queue_limits_stack_bdev);
+
+/**
* disk_stack_limits - adjust queue limits for stacked drivers
* @disk: MD/DM gendisk (top)
* @bdev: the underlying block device (bottom)