From 9d346718bee344c97e4214021c0dd42078195622 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 21 Mar 2012 16:34:17 -0700 Subject: [PATCH] swap: don't do discard if no discard option added commit 052b1987faca3606109d88d96bce124851f7c4c2 upstream. When swapon() was not passed the SWAP_FLAG_DISCARD option, sys_swapon() will still perform a discard operation. This can cause problems if discard is slow or buggy. Reverse the order of the check so that a discard operation is performed only if the sys_swapon() caller is attempting to enable discard. Signed-off-by: Shaohua Li Reported-by: Holger Kiehl Tested-by: Holger Kiehl Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Konrad Rzeszutek Wilk Cc: William Dauchy Signed-off-by: Greg Kroah-Hartman --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index f31b29d2ca4e..099c20963616 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2103,7 +2103,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) p->flags |= SWP_SOLIDSTATE; p->cluster_next = 1 + (random32() % p->highest_bit); } - if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD)) + if ((swap_flags & SWAP_FLAG_DISCARD) && discard_swap(p) == 0) p->flags |= SWP_DISCARDABLE; } -- 2.11.4.GIT