From: Andrew Morton <akpm@linux-foundation.org>
Date: Fri, 8 Jan 2010 22:42:39 +0000 (-0800)
Subject: percpu: avoid calling __pcpu_ptr_to_addr(NULL)
X-Git-Tag: v2.6.33-rc4~57
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=129182e5626972ac0df85d43a36dd46ad61c64e1;p=~emulex%2Finfiniband.git

percpu: avoid calling __pcpu_ptr_to_addr(NULL)

__pcpu_ptr_to_addr() can be overridden by the architecture and might not
behave well if passed a NULL pointer.  So avoid calling it until we have
verified that its arg is not NULL.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/percpu.c b/mm/percpu.c
index 442010cc91c..083e7c91e5f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1271,7 +1271,7 @@ static void pcpu_reclaim(struct work_struct *work)
  */
 void free_percpu(void *ptr)
 {
-	void *addr = __pcpu_ptr_to_addr(ptr);
+	void *addr;
 	struct pcpu_chunk *chunk;
 	unsigned long flags;
 	int off;
@@ -1279,6 +1279,8 @@ void free_percpu(void *ptr)
 	if (!ptr)
 		return;
 
+	addr = __pcpu_ptr_to_addr(ptr);
+
 	spin_lock_irqsave(&pcpu_lock, flags);
 
 	chunk = pcpu_chunk_addr_search(addr);