From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Date: Tue, 5 Nov 2013 05:55:41 +0000 (+1100)
Subject: frontswap: enable call to invalidate area on swapoff
X-Git-Tag: next-20131105~2^2~239
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=89d4767399b00d208f997d789a3a0fe5e24f2bb4;p=karo-tx-linux.git

frontswap: enable call to invalidate area on swapoff

During swapoff the frontswap_map was NULL-ified before calling
frontswap_invalidate_area().  However the frontswap_invalidate_area()
exits early if frontswap_map is NULL.  Invalidate was never called during
swapoff.

This patch moves frontswap_map_set() in swapoff just after calling
frontswap_invalidate_area() so outside of locks (swap_lock and
swap_info_struct->lock).  This shouldn't be a problem as during swapon the
frontswap_map_set() is called also outside of any locks.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 64458e3997bc..612a7c9795f6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1924,10 +1924,10 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
 	p->cluster_info = NULL;
 	p->flags = 0;
 	frontswap_map = frontswap_map_get(p);
-	frontswap_map_set(p, NULL);
 	spin_unlock(&p->lock);
 	spin_unlock(&swap_lock);
 	frontswap_invalidate_area(type);
+	frontswap_map_set(p, NULL);
 	mutex_unlock(&swapon_mutex);
 	free_percpu(p->percpu_cluster);
 	p->percpu_cluster = NULL;