[PATCH] dax: Release PMD lock even when there is no PMD support in DAX

From: "Jan H. Schönherr" <jschoenh@amazon.de>
To: Matthew Wilcox <mawilcox@microsoft.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: "Jan H. Schönherr" <jschoenh@amazon.de>, linux-fsdevel@vger.kernel.org
Subject: [PATCH] dax: Release PMD lock even when there is no PMD support in DAX
Date: Thu, 18 Jan 2018 14:38:39 +0100	[thread overview]
Message-ID: <20180118133839.20587-1-jschoenh@amazon.de> (raw)

The function follow_pte_pmd() can theoretically return after having
acquired a PMD lock, even when DAX was not compiled with
CONFIG_FS_DAX_PMD.

Release the PMD lock unconditionally.

Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
---
 fs/dax.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/dax.c b/fs/dax.c
index 9598159..c2ebf10 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -636,8 +636,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
 			pmd = pmd_mkclean(pmd);
 			set_pmd_at(vma->vm_mm, address, pmdp, pmd);
 unlock_pmd:
-			spin_unlock(ptl);
 #endif
+			spin_unlock(ptl);
 		} else {
 			if (pfn != pte_pfn(*ptep))
 				goto unlock_pte;
-- 
2.9.3.1.gcba166c.dirty
