[5.4,100/155] mm/swapfile.c: move inode_lock out of claim_swapfile

--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2892,10 +2892,6 @@  static int claim_swapfile(struct swap_in
 		p->bdev = inode->i_sb->s_bdev;
 	}
 
-	inode_lock(inode);
-	if (IS_SWAPFILE(inode))
-		return -EBUSY;
-
 	return 0;
 }
 
@@ -3150,17 +3146,22 @@  SYSCALL_DEFINE2(swapon, const char __use
 	mapping = swap_file->f_mapping;
 	inode = mapping->host;
 
-	/* If S_ISREG(inode->i_mode) will do inode_lock(inode); */
 	error = claim_swapfile(p, inode);
 	if (unlikely(error))
 		goto bad_swap;
 
+	inode_lock(inode);
+	if (IS_SWAPFILE(inode)) {
+		error = -EBUSY;
+		goto bad_swap_unlock_inode;
+	}
+
 	/*
 	 * Read the swap header.
 	 */
 	if (!mapping->a_ops->readpage) {
 		error = -EINVAL;
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 	}
 	page = read_mapping_page(mapping, 0, swap_file);
 	if (IS_ERR(page)) {
@@ -3172,14 +3173,14 @@  SYSCALL_DEFINE2(swapon, const char __use
 	maxpages = read_swap_header(p, swap_header, inode);
 	if (unlikely(!maxpages)) {
 		error = -EINVAL;
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 	}
 
 	/* OK, set up the swap map and apply the bad block list */
 	swap_map = vzalloc(maxpages);
 	if (!swap_map) {
 		error = -ENOMEM;
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 	}
 
 	if (bdi_cap_stable_pages_required(inode_to_bdi(inode)))
@@ -3204,7 +3205,7 @@  SYSCALL_DEFINE2(swapon, const char __use
 					GFP_KERNEL);
 		if (!cluster_info) {
 			error = -ENOMEM;
-			goto bad_swap;
+			goto bad_swap_unlock_inode;
 		}
 
 		for (ci = 0; ci < nr_cluster; ci++)
@@ -3213,7 +3214,7 @@  SYSCALL_DEFINE2(swapon, const char __use
 		p->percpu_cluster = alloc_percpu(struct percpu_cluster);
 		if (!p->percpu_cluster) {
 			error = -ENOMEM;
-			goto bad_swap;
+			goto bad_swap_unlock_inode;
 		}
 		for_each_possible_cpu(cpu) {
 			struct percpu_cluster *cluster;
@@ -3227,13 +3228,13 @@  SYSCALL_DEFINE2(swapon, const char __use
 
 	error = swap_cgroup_swapon(p->type, maxpages);
 	if (error)
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 
 	nr_extents = setup_swap_map_and_extents(p, swap_header, swap_map,
 		cluster_info, maxpages, &span);
 	if (unlikely(nr_extents < 0)) {
 		error = nr_extents;
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 	}
 	/* frontswap enabled? set up bit-per-page map for frontswap */
 	if (IS_ENABLED(CONFIG_FRONTSWAP))
@@ -3273,7 +3274,7 @@  SYSCALL_DEFINE2(swapon, const char __use
 
 	error = init_swap_address_space(p->type, maxpages);
 	if (error)
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 
 	/*
 	 * Flush any pending IO and dirty mappings before we start using this
@@ -3283,7 +3284,7 @@  SYSCALL_DEFINE2(swapon, const char __use
 	error = inode_drain_writes(inode);
 	if (error) {
 		inode->i_flags &= ~S_SWAPFILE;
-		goto bad_swap;
+		goto bad_swap_unlock_inode;
 	}
 
 	mutex_lock(&swapon_mutex);
@@ -3308,6 +3309,8 @@  SYSCALL_DEFINE2(swapon, const char __use
 
 	error = 0;
 	goto out;
+bad_swap_unlock_inode:
+	inode_unlock(inode);
 bad_swap:
 	free_percpu(p->percpu_cluster);
 	p->percpu_cluster = NULL;
@@ -3315,6 +3318,7 @@  bad_swap:
 		set_blocksize(p->bdev, p->old_block_size);
 		blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 	}
+	inode = NULL;
 	destroy_swap_extents(p);
 	swap_cgroup_swapoff(p->type);
 	spin_lock(&swap_lock);
@@ -3326,13 +3330,8 @@  bad_swap:
 	kvfree(frontswap_map);
 	if (inced_nr_rotate_swap)
 		atomic_dec(&nr_rotate_swap);
-	if (swap_file) {
-		if (inode) {
-			inode_unlock(inode);
-			inode = NULL;
-		}
+	if (swap_file)
 		filp_close(swap_file, NULL);
-	}
 out:
 	if (page && !IS_ERR(page)) {
 		kunmap(page);