[PATCH 1/2] statx: allow the system call to be invoked from the kernel

[Bijan Mottahedeh <bijan.mottahedeh@oracle.com>]

This is a prepatory patch to allow io_uring to invoke statx directly.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/internal.h |  2 ++
 fs/stat.c     | 32 +++++++++++++++++++-------------
 2 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index aaa946d..37055a4 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -203,3 +203,5 @@ int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
  */
 unsigned vfs_stat_set_lookup_flags(unsigned *lookup_flags, int flags);
 int cp_statx(const struct kstat *stat, struct statx __user *buffer);
+int do_statx(int dfd, const char __user *filename, unsigned flags,
+	     unsigned int mask, struct statx __user *buffer);
diff --git a/fs/stat.c b/fs/stat.c
index 3213d1b..bc5d2e81 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -577,6 +577,24 @@ static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
 
+int do_statx(int dfd, const char __user *filename, unsigned flags,
+	     unsigned int mask, struct statx __user *buffer)
+{
+	struct kstat stat;
+	int error;
+
+	if (mask & STATX__RESERVED)
+		return -EINVAL;
+	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
+		return -EINVAL;
+
+	error = vfs_statx(dfd, filename, flags, &stat, mask);
+	if (error)
+		return error;
+
+	return cp_statx(&stat, buffer);
+}
+
 /**
  * sys_statx - System call to get enhanced stats
  * @dfd: Base directory to pathwalk from *or* fd to stat.
@@ -593,19 +611,7 @@ static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 		unsigned int, mask,
 		struct statx __user *, buffer)
 {
-	struct kstat stat;
-	int error;
-
-	if (mask & STATX__RESERVED)
-		return -EINVAL;
-	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
-		return -EINVAL;
-
-	error = vfs_statx(dfd, filename, flags, &stat, mask);
-	if (error)
-		return error;
-
-	return cp_statx(&stat, buffer);
+	return do_statx(dfd, filename, flags, mask, buffer);
 }
 
 #ifdef CONFIG_COMPAT
-- 
1.8.3.1