[patch 2/6] mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled

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From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled

/sys/kernel/mm/transparent_hugepage/shmem_enabled controls if we want to
allocate huge pages when allocate pages for private in-kernel shmem mount.

Unfortunately, as Dan noticed, I've screwed it up and the only way to make
kernel allocate huge page for the mount is to use "force" there.  All
other values will be effectively ignored.

Link: http://lkml.kernel.org/r/20170822144254.66431-1-kirill.shutemov@xxxxxxxxxxxxxxx
Fixes: 5a6e75f8110c ("shmem: prepare huge= mount option and sysfs knob")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx> [4.8+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/shmem.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN mm/shmem.c~mm-shmem-fix-handling-sys-kernel-mm-transparent_hugepage-shmem_enabled mm/shmem.c
--- a/mm/shmem.c~mm-shmem-fix-handling-sys-kernel-mm-transparent_hugepage-shmem_enabled
+++ a/mm/shmem.c
@@ -3967,7 +3967,7 @@ int __init shmem_init(void)
 	}
 
 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
-	if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY)
+	if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
 		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
 	else
 		shmem_huge = 0; /* just in case it was patched */
@@ -4028,7 +4028,7 @@ static ssize_t shmem_enabled_store(struc
 		return -EINVAL;
 
 	shmem_huge = huge;
-	if (shmem_huge < SHMEM_HUGE_DENY)
+	if (shmem_huge > SHMEM_HUGE_DENY)
 		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
 	return count;
 }
_



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