file ->get_unmapped_area() shouldn't duplicate work of get_unmapped_area()

... we should call mm ->get_unmapped_area() instead and let our caller
do the final checks.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 14 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 464694e0aa4a..11bec626c228 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -290,28 +290,28 @@ static unsigned long shm_get_unmapped_area(struct file *file,
 	unsigned long flags)
 {
 	struct shm_file_data *sfd = shm_file_data(file);
-	return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
-}
-
-int is_file_shm_hugepages(struct file *file)
-{
-	int ret = 0;
-
-	if (file->f_op == &shm_file_operations) {
-		struct shm_file_data *sfd;
-		sfd = shm_file_data(file);
-		ret = is_file_hugepages(sfd->file);
-	}
-	return ret;
+	return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
+						pgoff, flags);
 }
 
 static const struct file_operations shm_file_operations = {
 	.mmap		= shm_mmap,
 	.fsync		= shm_fsync,
 	.release	= shm_release,
+};
+
+static const struct file_operations shm_file_operations_huge = {
+	.mmap		= shm_mmap,
+	.fsync		= shm_fsync,
+	.release	= shm_release,
 	.get_unmapped_area	= shm_get_unmapped_area,
 };
 
+int is_file_shm_hugepages(struct file *file)
+{
+	return file->f_op == &shm_file_operations_huge;
+}
+
 static const struct vm_operations_struct shm_vm_ops = {
 	.open	= shm_open,	/* callback for a new vm-area open */
 	.close	= shm_close,	/* callback for when the vm-area is released */
@@ -889,7 +889,10 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 	if (!sfd)
 		goto out_put_dentry;
 
-	file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
+	file = alloc_file(path.mnt, path.dentry, f_mode,
+			is_file_hugepages(shp->shm_file) ?
+				&shm_file_operations_huge :
+				&shm_file_operations);
 	if (!file)
 		goto out_free;
 	ima_counts_get(file);