From: Benjamin LaHaise <bcrl@kvack.org>
Date: Wed, 31 Jul 2013 14:34:18 +0000 (-0400)
Subject: aio: be defensive to ensure request batching is non-zero instead of BUG_ON()
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=6878ea72a5d1aa6caae86449975a50b7fe9abed5;p=deliverable%2Flinux.git

aio: be defensive to ensure request batching is non-zero instead of BUG_ON()

In the event that an overflow/underflow occurs while calculating req_batch,
clamp the minimum at 1 request instead of doing a BUG_ON().

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
---

diff --git a/fs/aio.c b/fs/aio.c
index 52f200ebef07..588aff9dc316 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -576,7 +576,8 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
 
 	atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
 	ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
-	BUG_ON(!ctx->req_batch);
+	if (ctx->req_batch < 1)
+		ctx->req_batch = 1;
 
 	err = ioctx_add_table(ctx, mm);
 	if (err)