From: Tejun Heo <tj@kernel.org>
Date: Fri, 15 Aug 2014 20:06:10 +0000 (-0400)
Subject: percpu: perform tlb flush after pcpu_map_pages() failure
X-Git-Tag: v3.17-rc5~39^2~1
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=849f5169097e1ba35b90ac9df76b5bb6f9c0aabd;p=linux.git

percpu: perform tlb flush after pcpu_map_pages() failure

If pcpu_map_pages() fails midway, it unmaps the already mapped pages.
Currently, it doesn't flush tlb after the partial unmapping.  This may
be okay in most cases as the established mapping hasn't been used at
that point but it can go wrong and when it goes wrong it'd be
extremely difficult to track down.

Flush tlb after the partial unmapping.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
---

diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 8d9bb2c00c68..51108165f829 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -272,6 +272,7 @@ static int pcpu_map_pages(struct pcpu_chunk *chunk,
 		__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
 				   page_end - page_start);
 	}
+	pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
 	return err;
 }