[RFC] blk: increase logical_block_size to unsigned int

Minchan Kim
2017-01-09T05:04:34Z

Mostly, zram is used as swap system on embedded world so it want to do IO
as PAGE_SIZE aligned/size IO unit. For that, one of the problem was
blk_queue_logical_block_size(zram->disk->queue, PAGE_SIZE) made overflow
in *64K page system* so [1] changed it to constant 4096.
Since that, partial IO can happen so zram should handle it which makes zram
complicated[2].

Now, I want to remove that partial IO handling logics in zram.

Block guys, Robert, Jerome:

Can't we extend q->limits.logical_block_size to unsigned int?
Is there any problem on that?

[1] 7b19b8d45b21, zram: Prevent overflow in logical block size
[2] 924bd88d703e, zram: allow partial page operations

Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
block/blk-settings.c | 2 +-
include/linux/blkdev.h | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index f679ae122843..0d644f37e3c6 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -349,7 +349,7 @@ EXPORT_SYMBOL(blk_queue_max_segment_size);
* storage device can address. The default of 512 covers most
* hardware.
**/
-void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
+void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
{
q->limits.logical_block_size = size;

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c47c358ba052..0aaea317a7f4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -281,7 +281,7 @@ struct queue_limits {
unsigned int discard_granularity;
unsigned int discard_alignment;

- unsigned short logical_block_size;
+ unsigned int logical_block_size;
unsigned short max_segments;
unsigned short max_integrity_segments;

@@ -991,7 +991,7 @@ extern void blk_queue_max_discard_sectors(struct request_queue *q,
unsigned int max_discard_sectors);
extern void blk_queue_max_write_same_sectors(struct request_queue *q,
unsigned int max_write_same_sectors);
-extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
+extern void blk_queue_logical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_alignment_offset(struct request_queue *q,
unsigned int alignment);
@@ -1216,9 +1216,9 @@ static inline unsigned int queue_max_segment_size(struct request_queue *q)
return q->limits.max_segment_size;
}

-static inline unsigned short queue_logical_block_size(struct request_queue *q)
+static inline unsigned int queue_logical_block_size(struct request_queue *q)
{
- int retval = 512;
+ unsigned int retval = 512;

if (q && q->limits.logical_block_size)
retval = q->limits.logical_block_size;
@@ -1226,7 +1226,7 @@ static inline unsigned short queue_logical_block_size(struct request_queue *q)
return retval;
}

-static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
+static inline unsigned int bdev_logical_block_size(struct block_device *bdev)
{
return queue_logical_block_size(bdev_get_queue(bdev));
}
--
2.7.4