[Nbd] [PATCH v2 1/9] block: fix max discard sectors limit
- To: dwmw2@...1270..., axboe@...161..., shli@...1285..., Paul.Clements@...124..., npiggin@...161..., neilb@...122..., cjb@...1330..., adrian.hunter@...1303..., James.Bottomley@...1336..., JBottomley@...1298...
- Cc: nbd-general@lists.sourceforge.net, Namjae Jeon <linkinjeon@...17...>, Vivek Trivedi <t.vivek@...1329...>, linux-scsi@...25..., Namjae Jeon <namjae.jeon@...1329...>, linux-mmc@...25..., linux-kernel@...25..., linux-raid@...25..., jcmvbkbc@...17..., linux-mtd@...1331...
- Subject: [Nbd] [PATCH v2 1/9] block: fix max discard sectors limit
- From: Namjae Jeon <linkinjeon@...17...>
- Date: Sat, 20 Apr 2013 01:40:33 +0900
- Message-id: <1366389634-19348-1-git-send-email-linkinjeon@...17...>
From: Namjae Jeon <namjae.jeon@...1329...>
https://lkml.org/lkml/2013/4/1/292
As per above discussion, it has been oberved that few drivers are
setting q->limits.max_discard_sectors to more than (UINT_MAX >> 9)
If multiple discard requests get merged, merged discard request's
size exceeds 4GB, there is possibility that merged discard request's
__data_len field may overflow.
This patch fixes this issue.
Also, adding BLK_DEF_MAX_DISCARD_SECTORS macro to use it instead
of UINT_MAX >> 9.
Reported-by: Max Filippov <jcmvbkbc@...17...>
Signed-off-by: Namjae Jeon <namjae.jeon@...1329...>
Signed-off-by: Vivek Trivedi <t.vivek@...1329...>
---
block/blk-settings.c | 3 ++-
include/linux/blkdev.h | 1 +
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/block/blk-settings.c b/block/blk-settings.c
index c50ecf0..34e6b61 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -283,7 +283,8 @@ EXPORT_SYMBOL(blk_queue_max_hw_sectors);
void blk_queue_max_discard_sectors(struct request_queue *q,
unsigned int max_discard_sectors)
{
- q->limits.max_discard_sectors = max_discard_sectors;
+ q->limits.max_discard_sectors = min_t(unsigned int, max_discard_sectors,
+ BLK_DEF_MAX_DISCARD_SECTORS);
}
EXPORT_SYMBOL(blk_queue_max_discard_sectors);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 07aa5f6..efff505 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1105,6 +1105,7 @@ enum blk_default_limits {
BLK_DEF_MAX_SECTORS = 1024,
BLK_MAX_SEGMENT_SIZE = 65536,
BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL,
+ BLK_DEF_MAX_DISCARD_SECTORS = UINT_MAX >> 9,
};
#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
--
1.7.9.5
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