This is a note to let you know that I've just added the patch titled
bql: Avoid possible inconsistent calculation.
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bql-avoid-possible-inconsistent-calculation.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 3cf098894a2fb3d8ec74103ed29f8fadfc727c73 Mon Sep 17 00:00:00 2001
From: Hiroaki SHIMODA <[email protected]>
Date: Wed, 30 May 2012 12:25:37 +0000
Subject: bql: Avoid possible inconsistent calculation.
From: Hiroaki SHIMODA <[email protected]>
[ Upstream commit 914bec1011a25f65cdc94988a6f974bfb9a3c10d ]
dql->num_queued could change while processing dql_completed().
To provide consistent calculation, added an on stack variable.
Signed-off-by: Hiroaki SHIMODA <[email protected]>
Cc: Tom Herbert <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Denys Fedoryshchenko <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
lib/dynamic_queue_limits.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -17,16 +17,18 @@
void dql_completed(struct dql *dql, unsigned int count)
{
unsigned int inprogress, prev_inprogress, limit;
- unsigned int ovlimit, completed;
+ unsigned int ovlimit, completed, num_queued;
bool all_prev_completed;
+ num_queued = ACCESS_ONCE(dql->num_queued);
+
/* Can't complete more than what's in queue */
- BUG_ON(count > dql->num_queued - dql->num_completed);
+ BUG_ON(count > num_queued - dql->num_completed);
completed = dql->num_completed + count;
limit = dql->limit;
- ovlimit = POSDIFF(dql->num_queued - dql->num_completed, limit);
- inprogress = dql->num_queued - completed;
+ ovlimit = POSDIFF(num_queued - dql->num_completed, limit);
+ inprogress = num_queued - completed;
prev_inprogress = dql->prev_num_queued - dql->num_completed;
all_prev_completed = AFTER_EQ(completed, dql->prev_num_queued);
@@ -106,7 +108,7 @@ void dql_completed(struct dql *dql, unsi
dql->prev_ovlimit = ovlimit;
dql->prev_last_obj_cnt = dql->last_obj_cnt;
dql->num_completed = completed;
- dql->prev_num_queued = dql->num_queued;
+ dql->prev_num_queued = num_queued;
}
EXPORT_SYMBOL(dql_completed);
Patches currently in stable-queue which might be from [email protected]
are
queue-3.4/bql-avoid-possible-inconsistent-calculation.patch
queue-3.4/bql-avoid-unneeded-limit-decrement.patch
queue-3.4/bql-fix-posdiff-to-integer-overflow-aware.patch
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