linux-kernel - [PATCH 5/5] bio: use bio_kmalloc() in copy/map functions

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Date:	Wed, 15 Apr 2009 22:10:27 +0900
From:	Tejun Heo <tj@...nel.org>
To:	axboe@...nel.dk, bharrosh@...asas.com,
	linux-kernel@...r.kernel.org, fujita.tomonori@....ntt.co.jp
Cc:	Tejun Heo <tj@...nel.org>
Subject: [PATCH 5/5] bio: use bio_kmalloc() in copy/map functions

Impact: remove possible deadlock condition

There is no reason to use mempool backed allocation for map functions.
Also, because kern mapping is used inside LLDs (e.g. for EH), using
mempool backed allocation can lead to deadlock under extreme
conditions (mempool already consumed by the time a request reached EH
and requests are blocked on EH).

Switch copy/map functions to bio_kmalloc().

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 fs/bio.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index 6c2aef6..eba1804 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -816,7 +816,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 		return ERR_PTR(-ENOMEM);
 
 	ret = -ENOMEM;
-	bio = bio_alloc(gfp_mask, nr_pages);
+	bio = bio_kmalloc(gfp_mask, nr_pages);
 	if (!bio)
 		goto out_bmd;
 
@@ -940,7 +940,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
 	if (!nr_pages)
 		return ERR_PTR(-EINVAL);
 
-	bio = bio_alloc(gfp_mask, nr_pages);
+	bio = bio_kmalloc(gfp_mask, nr_pages);
 	if (!bio)
 		return ERR_PTR(-ENOMEM);
 
@@ -1124,7 +1124,7 @@ static struct bio *__bio_map_kern(struct request_queue *q, void *data,
 	int offset, i;
 	struct bio *bio;
 
-	bio = bio_alloc(gfp_mask, nr_pages);
+	bio = bio_kmalloc(gfp_mask, nr_pages);
 	if (!bio)
 		return ERR_PTR(-ENOMEM);
 
-- 
1.6.0.2

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