linux-kernel - [PATCH 1/3] shmem: fix double uncharge in __shmem_file

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Message-ID: <20140624201606.18273.44270.stgit@zurg>
Date:	Wed, 25 Jun 2014 00:16:06 +0400
From:	Konstantin Khlebnikov <koct9i@...il.com>
To:	linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>
Cc:	Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] shmem: fix double uncharge in __shmem_file_setup()

If __shmem_file_setup() fails on struct file allocation it uncharges memory
commitment twice: first by shmem_unacct_size() and second time implicitly in
shmem_evict_inode() when it kills newly created inode.
This patch removes shmem_unacct_size() from error path if inode already here.

Signed-off-by: Konstantin Khlebnikov <koct9i@...il.com>
---
 mm/shmem.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 8f419cf..0aabcbd 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2895,16 +2895,16 @@ static struct file *__shmem_file_setup(const char *name, loff_t size,
 	this.len = strlen(name);
 	this.hash = 0; /* will go */
 	sb = shm_mnt->mnt_sb;
+	path.mnt = mntget(shm_mnt);
 	path.dentry = d_alloc_pseudo(sb, &this);
 	if (!path.dentry)
 		goto put_memory;
 	d_set_d_op(path.dentry, &anon_ops);
-	path.mnt = mntget(shm_mnt);
 
 	res = ERR_PTR(-ENOSPC);
 	inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags);
 	if (!inode)
-		goto put_dentry;
+		goto put_memory;
 
 	inode->i_flags |= i_flags;
 	d_instantiate(path.dentry, inode);
@@ -2912,19 +2912,19 @@ static struct file *__shmem_file_setup(const char *name, loff_t size,
 	clear_nlink(inode);	/* It is unlinked */
 	res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
 	if (IS_ERR(res))
-		goto put_dentry;
+		goto put_path;
 
 	res = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 		  &shmem_file_operations);
 	if (IS_ERR(res))
-		goto put_dentry;
+		goto put_path;
 
 	return res;
 
-put_dentry:
-	path_put(&path);
 put_memory:
 	shmem_unacct_size(flags, size);
+put_path:
+	path_put(&path);
 	return res;
 }
 

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