[PATCH v1 3/5] fs: split off the vfs_getxattr from getxattr

[Stefan Roesch <shr@fb.com>]

Summary:

This splits off vfs_getxattr call from the getxattr
function. This will allow io_uring to call it from
its io worker.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
 fs/internal.h |  6 ++++++
 fs/xattr.c    | 37 +++++++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index c5c82bfb5ecf..9805415b199c 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -208,6 +208,12 @@ struct xattr_ctx {
 	int flags;
 };
 
+ssize_t do_getxattr(struct user_namespace *mnt_userns,
+		    struct dentry *d,
+		    const char *kname,
+		    void __user *value,
+		    size_t size);
+
 void *setxattr_setup(struct user_namespace *mnt_userns,
 		     const char __user *name,
 		     struct xattr_ctx *data);
diff --git a/fs/xattr.c b/fs/xattr.c
index 13963b914ac5..9e1dba601a03 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -666,19 +666,12 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
 /*
  * Extended attribute GET operations
  */
-static ssize_t
-getxattr(struct user_namespace *mnt_userns, struct dentry *d,
-	 const char __user *name, void __user *value, size_t size)
+ssize_t
+do_getxattr(struct user_namespace *mnt_userns, struct dentry *d,
+	 const char *name, void __user *value, size_t size)
 {
-	ssize_t error;
 	void *kvalue = NULL;
-	char kname[XATTR_NAME_MAX + 1];
-
-	error = strncpy_from_user(kname, name, sizeof(kname));
-	if (error == 0 || error == sizeof(kname))
-		error = -ERANGE;
-	if (error < 0)
-		return error;
+	size_t error;
 
 	if (size) {
 		if (size > XATTR_SIZE_MAX)
@@ -688,10 +681,10 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d,
 			return -ENOMEM;
 	}
 
-	error = vfs_getxattr(mnt_userns, d, kname, kvalue, size);
+	error = vfs_getxattr(mnt_userns, d, name, kvalue, size);
 	if (error > 0) {
-		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
+		if ((strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
+		    (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
 			posix_acl_fix_xattr_to_user(mnt_userns, kvalue, error);
 		if (size && copy_to_user(value, kvalue, error))
 			error = -EFAULT;
@@ -706,6 +699,22 @@ getxattr(struct user_namespace *mnt_userns, struct dentry *d,
 	return error;
 }
 
+static ssize_t
+getxattr(struct user_namespace *mnt_userns, struct dentry *d,
+	 const char __user *name, void __user *value, size_t size)
+{
+	ssize_t error;
+	char kname[XATTR_NAME_MAX + 1];
+
+	error = strncpy_from_user(kname, name, sizeof(kname));
+	if (error == 0 || error == sizeof(kname))
+		error = -ERANGE;
+	if (error < 0)
+		return error;
+
+	return do_getxattr(mnt_userns, d, kname, value, size);
+}
+
 static ssize_t path_getxattr(const char __user *pathname,
 			     const char __user *name, void __user *value,
 			     size_t size, unsigned int lookup_flags)
-- 
2.30.2