linux-kernel - [PATCH -mmotm 27/30] nfs: fix various memory recursions possible with swap over NFS

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Message-Id: <20100713102155.2835.71936.sendpatchset@danny.redhat>
Date:	Tue, 13 Jul 2010 06:21:55 -0400
From:	Xiaotian Feng <dfeng@...hat.com>
To:	linux-mm@...ck.org, linux-nfs@...r.kernel.org,
	netdev@...r.kernel.org
Cc:	riel@...hat.com, cl@...ux-foundation.org, a.p.zijlstra@...llo.nl,
	Xiaotian Feng <dfeng@...hat.com>, linux-kernel@...r.kernel.org,
	lwang@...hat.com, penberg@...helsinki.fi,
	akpm@...ux-foundation.org, davem@...emloft.net
Subject: [PATCH -mmotm 27/30] nfs: fix various memory recursions possible with swap over NFS

>From df0106f58d7ac2337f74efb1d8caaf27f635e050 Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <dfeng@...hat.com>
Date: Tue, 13 Jul 2010 13:11:32 +0800
Subject: [PATCH 27/30] nfs: fix various memory recursions possible with swap over NFS.

GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate IO,
just not of any filesystem data.

The problem is that previuosly NOFS was correct because that avoids
recursion into the NFS code, it now is not, because also IO (swap) can
lead to this recursion.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Signed-off-by: Suresh Jayaraman <sjayaraman@...e.de>
Signed-off-by: Xiaotian Feng <dfeng@...hat.com>
---
 fs/nfs/pagelist.c |    2 +-
 fs/nfs/write.c    |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 2be94bb..c0247e9 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -27,7 +27,7 @@ static inline struct nfs_page *
 nfs_page_alloc(void)
 {
 	struct nfs_page	*p;
-	p = kmem_cache_alloc(nfs_page_cachep, GFP_KERNEL);
+	p = kmem_cache_alloc(nfs_page_cachep, GFP_NOIO);
 	if (p) {
 		memset(p, 0, sizeof(*p));
 		INIT_LIST_HEAD(&p->wb_list);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 5852b20..dfa08cb 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -50,7 +50,7 @@ static mempool_t *nfs_commit_mempool;
 
 struct nfs_write_data *nfs_commitdata_alloc(void)
 {
-	struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
+	struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
 
 	if (p) {
 		memset(p, 0, sizeof(*p));
@@ -69,7 +69,7 @@ void nfs_commit_free(struct nfs_write_data *p)
 
 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
 {
-	struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
+	struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
 
 	if (p) {
 		memset(p, 0, sizeof(*p));
@@ -79,7 +79,7 @@ struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
 		if (pagecount <= ARRAY_SIZE(p->page_array))
 			p->pagevec = p->page_array;
 		else {
-			p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
+			p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOIO);
 			if (!p->pagevec) {
 				mempool_free(p, nfs_wdata_mempool);
 				p = NULL;
-- 
1.7.1.1

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