[dm-devel] [RFC][PATCH 1/2] block: add blk_limits_io_min() and stack io_opt
Mike Snitzer
snitzer at gmail.com
Fri Jun 26 04:55:15 UTC 2009
Introduce blk_limits_io_min() and make blk_queue_io_min() call it.
blk_stack_limits() doesn't stack io_opt and DM needs it to.
---
block/blk-settings.c | 32 +++++++++++++++++++++++++-------
include/linux/blkdev.h | 1 +
2 files changed, 26 insertions(+), 7 deletions(-)
Index: linux-2.6/block/blk-settings.c
===================================================================
--- linux-2.6.orig/block/blk-settings.c 2009-06-26 00:39:22.000000000 -0400
+++ linux-2.6/block/blk-settings.c 2009-06-26 00:40:35.000000000 -0400
@@ -377,6 +377,29 @@
EXPORT_SYMBOL(blk_queue_alignment_offset);
/**
+ * blk_limits_io_min - set minimum request size for a device
+ * @limits: the queue limits
+ * @min: smallest I/O size in bytes
+ *
+ * Description:
+ * Some devices have an internal block size bigger than the reported
+ * hardware sector size. This function can be used to signal the
+ * smallest I/O the device can perform without incurring a performance
+ * penalty.
+ */
+void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
+{
+ limits->io_min = min;
+
+ if (limits->io_min < limits->logical_block_size)
+ limits->io_min = limits->logical_block_size;
+
+ if (limits->io_min < limits->physical_block_size)
+ limits->io_min = limits->physical_block_size;
+}
+EXPORT_SYMBOL(blk_limits_io_min);
+
+/**
* blk_queue_io_min - set minimum request size for the queue
* @q: the request queue for the device
* @min: smallest I/O size in bytes
@@ -389,13 +412,7 @@
*/
void blk_queue_io_min(struct request_queue *q, unsigned int min)
{
- q->limits.io_min = min;
-
- if (q->limits.io_min < q->limits.logical_block_size)
- q->limits.io_min = q->limits.logical_block_size;
-
- if (q->limits.io_min < q->limits.physical_block_size)
- q->limits.io_min = q->limits.physical_block_size;
+ blk_limits_io_min(&q->limits, min);
}
EXPORT_SYMBOL(blk_queue_io_min);
@@ -496,6 +513,7 @@
b->physical_block_size);
t->io_min = max(t->io_min, b->io_min);
+ t->io_opt = min_not_zero(t->io_opt, b->io_opt);
t->no_cluster |= b->no_cluster;
/* Bottom device offset aligned? */
Index: linux-2.6/include/linux/blkdev.h
===================================================================
--- linux-2.6.orig/include/linux/blkdev.h 2009-06-26 00:39:22.000000000 -0400
+++ linux-2.6/include/linux/blkdev.h 2009-06-26 00:40:35.000000000 -0400
@@ -924,6 +924,7 @@
extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
extern void blk_queue_alignment_offset(struct request_queue *q,
unsigned int alignment);
+extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
extern void blk_set_default_limits(struct queue_limits *lim);
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