There is a default upper limitation BLK_DEF_MAX_SECTORS, but for
some virtual block device driver there is no such limitation. So
add a new help to set max request size.
Signed-off-by: Weiping Zhang <zhangweiping@xxxxxxxxxxxxxxx>
---
block/blk-settings.c | 20 ++++++++++++++++++++
include/linux/blkdev.h | 2 ++
2 files changed, 22 insertions(+)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 48ebe6b..685c30c 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -253,6 +253,26 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
}
EXPORT_SYMBOL(blk_queue_max_hw_sectors);
+/* same as blk_queue_max_hw_sectors but without default upper limitation */
+void blk_queue_max_hw_sectors_no_limit(struct request_queue *q,
+ unsigned int max_hw_sectors)
+{
+ struct queue_limits *limits = &q->limits;
+ unsigned int max_sectors;
+
+ if ((max_hw_sectors << 9) < PAGE_SIZE) {
+ max_hw_sectors = 1 << (PAGE_SHIFT - 9);
+ printk(KERN_INFO "%s: set to minimum %d\n",
+ __func__, max_hw_sectors);
+ }
+
+ limits->max_hw_sectors = max_hw_sectors;
+ max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
+ limits->max_sectors = max_sectors;
+ q->backing_dev_info->io_pages = max_sectors >> (PAGE_SHIFT - 9);
+}
+EXPORT_SYMBOL(blk_queue_max_hw_sectors_no_limit);
+
/**
* blk_queue_chunk_sectors - set size of the chunk for this queue
* @q: the request queue for the device
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ed63f3b..2250709 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1243,6 +1243,8 @@ extern void blk_cleanup_queue(struct request_queue *);
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
extern void blk_queue_bounce_limit(struct request_queue *, u64);
extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
+extern void blk_queue_max_hw_sectors_no_limit(struct request_queue *,
+ unsigned int);
extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
extern void blk_queue_max_segments(struct request_queue *, unsigned short);
extern void blk_queue_max_discard_segments(struct request_queue *,
--
2.9.4
