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-rw-r--r--block/blk-settings.c39
1 files changed, 35 insertions, 4 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index d52d4adc440b..5eeb9e0d256e 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -528,7 +528,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
sector_t offset)
{
sector_t alignment;
- unsigned int top, bottom;
+ unsigned int top, bottom, ret = 0;
t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
@@ -546,6 +546,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
t->max_segment_size = min_not_zero(t->max_segment_size,
b->max_segment_size);
+ t->misaligned |= b->misaligned;
+
alignment = queue_limit_alignment_offset(b, offset);
/* Bottom device has different alignment. Check that it is
@@ -558,8 +560,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
bottom = max(b->physical_block_size, b->io_min) + alignment;
/* Verify that top and bottom intervals line up */
- if (max(top, bottom) & (min(top, bottom) - 1))
+ if (max(top, bottom) & (min(top, bottom) - 1)) {
t->misaligned = 1;
+ ret = -1;
+ }
}
t->logical_block_size = max(t->logical_block_size,
@@ -578,18 +582,21 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
if (t->physical_block_size & (t->logical_block_size - 1)) {
t->physical_block_size = t->logical_block_size;
t->misaligned = 1;
+ ret = -1;
}
/* Minimum I/O a multiple of the physical block size? */
if (t->io_min & (t->physical_block_size - 1)) {
t->io_min = t->physical_block_size;
t->misaligned = 1;
+ ret = -1;
}
/* Optimal I/O a multiple of the physical block size? */
if (t->io_opt & (t->physical_block_size - 1)) {
t->io_opt = 0;
t->misaligned = 1;
+ ret = -1;
}
/* Find lowest common alignment_offset */
@@ -597,8 +604,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
& (max(t->physical_block_size, t->io_min) - 1);
/* Verify that new alignment_offset is on a logical block boundary */
- if (t->alignment_offset & (t->logical_block_size - 1))
+ if (t->alignment_offset & (t->logical_block_size - 1)) {
t->misaligned = 1;
+ ret = -1;
+ }
/* Discard alignment and granularity */
if (b->discard_granularity) {
@@ -626,11 +635,33 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
(t->discard_granularity - 1);
}
- return t->misaligned ? -1 : 0;
+ return ret;
}
EXPORT_SYMBOL(blk_stack_limits);
/**
+ * bdev_stack_limits - adjust queue limits for stacked drivers
+ * @t: the stacking driver limits (top device)
+ * @bdev: the component block_device (bottom)
+ * @start: first data sector within component device
+ *
+ * Description:
+ * Merges queue limits for a top device and a block_device. Returns
+ * 0 if alignment didn't change. Returns -1 if adding the bottom
+ * device caused misalignment.
+ */
+int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
+ sector_t start)
+{
+ struct request_queue *bq = bdev_get_queue(bdev);
+
+ start += get_start_sect(bdev);
+
+ return blk_stack_limits(t, &bq->limits, start << 9);
+}
+EXPORT_SYMBOL(bdev_stack_limits);
+
+/**
* disk_stack_limits - adjust queue limits for stacked drivers
* @disk: MD/DM gendisk (top)
* @bdev: the underlying block device (bottom)