#include <linux/blkdev.h>
#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/gcd.h>
+#include <linux/lcm.h>
#include "blk.h"
lim->alignment_offset = 0;
lim->io_opt = 0;
lim->misaligned = 0;
- lim->no_cluster = 0;
+ lim->cluster = 1;
}
EXPORT_SYMBOL(blk_set_default_limits);
* hardware can operate on without reverting to read-modify-write
* operations.
*/
-void blk_queue_physical_block_size(struct request_queue *q, unsigned short size)
+void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
{
q->limits.physical_block_size = size;
void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
{
blk_stack_limits(&t->limits, &b->limits, 0);
-
- if (!t->queue_lock)
- WARN_ON_ONCE(1);
- else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {
- unsigned long flags;
- spin_lock_irqsave(t->queue_lock, flags);
- queue_flag_clear(QUEUE_FLAG_CLUSTER, t);
- spin_unlock_irqrestore(t->queue_lock, flags);
- }
}
EXPORT_SYMBOL(blk_queue_stack_limits);
/**
* blk_stack_limits - adjust queue_limits for stacked devices
- * @t: the stacking driver limits (top)
- * @b: the underlying queue limits (bottom)
+ * @t: the stacking driver limits (top device)
+ * @b: the underlying queue limits (bottom, component device)
* @offset: offset to beginning of data within component device
*
* Description:
- * Merges two queue_limit structs. Returns 0 if alignment didn't
- * change. Returns -1 if adding the bottom device caused
- * misalignment.
+ * 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.
+ *
+ * Returns 0 if the top and bottom queue_limits are compatible. The
+ * top device's block sizes and alignment offsets may be adjusted to
+ * ensure alignment with the bottom device. If no compatible sizes
+ * and alignments exist, -1 is returned and the resulting top
+ * queue_limits will have the misaligned flag set to indicate that
+ * the alignment_offset is undefined.
*/
int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
sector_t offset)
{
+ sector_t alignment;
+ 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);
t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
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
+ * compatible with the current top alignment.
+ */
+ if (t->alignment_offset != alignment) {
+
+ top = max(t->physical_block_size, t->io_min)
+ + t->alignment_offset;
+ 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)) {
+ t->misaligned = 1;
+ ret = -1;
+ }
+ }
+
t->logical_block_size = max(t->logical_block_size,
b->logical_block_size);
b->physical_block_size);
t->io_min = max(t->io_min, b->io_min);
- t->no_cluster |= b->no_cluster;
+ t->io_opt = lcm(t->io_opt, b->io_opt);
+
+ t->cluster &= b->cluster;
- /* Bottom device offset aligned? */
- if (offset &&
- (offset & (b->physical_block_size - 1)) != b->alignment_offset) {
+ /* Physical block size a multiple of the logical block size? */
+ if (t->physical_block_size & (t->logical_block_size - 1)) {
+ t->physical_block_size = t->logical_block_size;
t->misaligned = 1;
- return -1;
+ ret = -1;
}
- /* If top has no alignment offset, inherit from bottom */
- if (!t->alignment_offset)
- t->alignment_offset =
- b->alignment_offset & (b->physical_block_size - 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;
+ }
- /* Top device aligned on logical block boundary? */
- if (t->alignment_offset & (t->logical_block_size - 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;
- return -1;
+ ret = -1;
}
- /* Find lcm() of optimal I/O size */
- if (t->io_opt && b->io_opt)
- t->io_opt = (t->io_opt * b->io_opt) / gcd(t->io_opt, b->io_opt);
- else if (b->io_opt)
- t->io_opt = b->io_opt;
+ /* Find lowest common alignment_offset */
+ t->alignment_offset = lcm(t->alignment_offset, alignment)
+ & (max(t->physical_block_size, t->io_min) - 1);
- /* Verify that optimal I/O size is a multiple of io_min */
- if (t->io_min && t->io_opt % t->io_min)
- return -1;
+ /* Verify that new alignment_offset is on a logical block boundary */
+ if (t->alignment_offset & (t->logical_block_size - 1)) {
+ t->misaligned = 1;
+ ret = -1;
+ }
- return 0;
+ /* Discard */
+ t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
+ b->max_discard_sectors);
+
+ 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)
printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
top, bottom);
}
-
- if (!t->queue_lock)
- WARN_ON_ONCE(1);
- else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {
- unsigned long flags;
-
- spin_lock_irqsave(t->queue_lock, flags);
- if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
- queue_flag_clear(QUEUE_FLAG_CLUSTER, t);
- spin_unlock_irqrestore(t->queue_lock, flags);
- }
}
EXPORT_SYMBOL(disk_stack_limits);
projects / firefly-linux-kernel-4.4.55.git / blobdiff