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From: Wei Yang <richard.weiyang@gmail.com>
To: akpm@linux-foundation.org, ying.huang@intel.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH 3/3] mm/swapfile.c: count won't be bigger than SWAP_MAP_MAX
Date: Fri,  1 May 2020 01:52:59 +0000	[thread overview]
Message-ID: <20200501015259.32237-3-richard.weiyang@gmail.com> (raw)
In-Reply-To: <20200501015259.32237-1-richard.weiyang@gmail.com>

When the condition is true, there are two possibilities:

   1. count == SWAP_MAP_BAD
   2. count == (SWAP_MAP_MAX & COUNT_CONTINUED) == SWAP_MAP_SHMEM

The first case would be filtered by the first if in __swap_duplicate().

And the second case means this swap entry is for shmem. Since we never
do another duplication for shmem swap entry. This won't happen neither.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 mm/swapfile.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1a877d1d40e3..88dd2ad34aad 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3404,8 +3404,6 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 
 		if ((count & ~COUNT_CONTINUED) < SWAP_MAP_MAX)
 			count += usage;
-		else if ((count & ~COUNT_CONTINUED) > SWAP_MAP_MAX)
-			err = -EINVAL;
 		else if (swap_count_continued(p, offset, count))
 			count = COUNT_CONTINUED;
 		else
-- 
2.23.0


  parent reply	other threads:[~2020-05-01  1:53 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-01  1:52 [PATCH 1/3] mm/swapfile.c: classify SWAP_MAP_XXX to make it more readable Wei Yang
2020-05-01  1:52 ` [PATCH 2/3] mm/swapfile.c: __swap_entry_free() always free 1 entry Wei Yang
2020-05-01  1:52 ` Wei Yang [this message]
2020-05-01 22:48   ` [PATCH 3/3] mm/swapfile.c: count won't be bigger than SWAP_MAP_MAX Andrew Morton
2020-05-02 13:29     ` Wei Yang
2020-05-02 13:41       ` Wei Yang
2020-05-06  8:22       ` Huang, Ying
2020-05-06  8:22         ` Huang, Ying
2020-05-07 22:20         ` Wei Yang
2020-05-07 23:48           ` Huang, Ying
2020-05-07 23:48             ` Huang, Ying
2020-05-08 21:19             ` Wei Yang

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