linux-kernel - [RFC][PATCH 30/42] ... and switch shmem_file_setup() to alloc_file

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Message-Id: <20180711022206.12571-30-viro@ZenIV.linux.org.uk>
Date:   Wed, 11 Jul 2018 03:21:54 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Miklos Szeredi <mszeredi@...hat.com>
Subject: [RFC][PATCH 30/42] ... and switch shmem_file_setup() to alloc_file_pseudo()

From: Al Viro <viro@...iv.linux.org.uk>

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 mm/shmem.c | 39 ++++++++-------------------------------
 1 file changed, 8 insertions(+), 31 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 1146a48926bc..fd21df189f32 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3896,18 +3896,11 @@ EXPORT_SYMBOL_GPL(shmem_truncate_range);
 
 /* common code */
 
-static const struct dentry_operations anon_ops = {
-	.d_dname = simple_dname
-};
-
 static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size,
 				       unsigned long flags, unsigned int i_flags)
 {
-	struct file *res;
 	struct inode *inode;
-	struct path path;
-	struct super_block *sb;
-	struct qstr this;
+	struct file *res;
 
 	if (IS_ERR(mnt))
 		return ERR_CAST(mnt);
@@ -3918,8 +3911,8 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
 	if (shmem_acct_size(flags, size))
 		return ERR_PTR(-ENOMEM);
 
-	sb = mnt->mnt_sb;
-	inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags);
+	inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,
+				flags);
 	if (unlikely(!inode)) {
 		shmem_unacct_size(flags, size);
 		return ERR_PTR(-ENOSPC);
@@ -3928,28 +3921,12 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
 	inode->i_size = size;
 	clear_nlink(inode);	/* It is unlinked */
 	res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
-	if (IS_ERR(res)) {
-		iput(inode);
-		return res;
-	}
-
-	this.name = name;
-	this.len = strlen(name);
-	this.hash = 0; /* will go */
-	path.mnt = mntget(mnt);
-	path.dentry = d_alloc_pseudo(sb, &this);
-	if (!path.dentry) {
-		iput(inode);
-		return ERR_PTR(-ENOMEM);
-	}
-	d_set_d_op(path.dentry, &anon_ops);
-
-	d_instantiate(path.dentry, inode);
-
-	res = alloc_file(&path, FMODE_WRITE | FMODE_READ,
-		  &shmem_file_operations);
+	if (!IS_ERR(res))
+		res = alloc_file_pseudo(inode, mnt, name,
+				FMODE_WRITE | FMODE_READ,
+				&shmem_file_operations);
 	if (IS_ERR(res))
-		path_put(&path);
+		iput(inode);
 	return res;
 }
 
-- 
2.11.0