[PATCH v2 2/4] mm, swap: Move setup_swap_clusters_info() after SWP_SOLIDSTATE initialization

[Kemeng Shi]

In setup_swap_clusters_info(), SWP_SOLIDSTATE is used to decide
global_cluster allocation. Move setup_swap_clusters_info() after
SWP_SOLIDSTATE initialization to avoid unneeded global_cluster
allocation.

Fixes: 451c6326105b2 ("mm, swap: clean up swapon process and locking")
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Reviewed-by: Luiz Capitulino <luizcap@xxxxxxxxxx>
---
 mm/swapfile.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 4561c864f806..e9554c28e6eb 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3592,11 +3592,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 
 	maxpages = si->max;
 
-	/* Set up the swap cluster info */
-	error = setup_swap_clusters_info(si, swap_header, maxpages);
-	if (error)
-		goto bad_swap_unlock_inode;
-
 	if (si->bdev && bdev_stable_writes(si->bdev))
 		si->flags |= SWP_STABLE_WRITES;
 
@@ -3610,6 +3605,14 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		inced_nr_rotate_swap = true;
 	}
 
+	/*
+	 * Set up the swap cluster info after SWP_ flags handling as
+	 * setup_swap_clusters_info() checks SWP_SOLIDSTATE.
+	 */
+	error = setup_swap_clusters_info(si, swap_header, maxpages);
+	if (error)
+		goto bad_swap_unlock_inode;
+
 	if ((swap_flags & SWAP_FLAG_DISCARD) &&
 	    si->bdev && bdev_max_discard_sectors(si->bdev)) {
 		/*
-- 
2.36.1