mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled

commit 435c0b87d661da83771c30ed775f7c37eed193fb upstream.

/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@linux.intel.com
Fixes: 5a6e75f8110c ("shmem: prepare huge= mount option and sysfs knob")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/shmem.c b/mm/shmem.c
index 1183e898743b6cd8841891c7973dace187616faa..0474c7a73cfa5f3c14d1023df9e379d8807ea973 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3964,7 +3964,7 @@ 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 */
@@ -4025,7 +4025,7 @@ static ssize_t shmem_enabled_store(struct kobject *kobj,
                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;
 }