[PATCH] Allow NULL pointers in percpu_free

The patch (as824b) makes percpu_free() ignore NULL arguments, as one would
expect for a deallocation routine.  (Note that free_percpu is #defined as
percpu_free in include/linux/percpu.h.) A few callers are updated to remove
now-unneeded tests for NULL.  A few other callers already seem to assume
that passing a NULL pointer to percpu_free() is okay!

The patch also removes an unnecessary NULL check in percpu_depopulate().

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/mm/allocpercpu.c b/mm/allocpercpu.c
index eaa9abeea536..b2486cf887a0 100644
--- a/mm/allocpercpu.c
+++ b/mm/allocpercpu.c
@@ -17,10 +17,9 @@
 void percpu_depopulate(void *__pdata, int cpu)
 {
         struct percpu_data *pdata = __percpu_disguise(__pdata);
-        if (pdata->ptrs[cpu]) {
-                kfree(pdata->ptrs[cpu]);
-                pdata->ptrs[cpu] = NULL;
-        }
+
+        kfree(pdata->ptrs[cpu]);
+        pdata->ptrs[cpu] = NULL;
 }
 EXPORT_SYMBOL_GPL(percpu_depopulate);
 
@@ -123,6 +122,8 @@ EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
  */
 void percpu_free(void *__pdata)
 {
+        if (unlikely(!__pdata))
+                return;
         __percpu_depopulate_mask(__pdata, &cpu_possible_map);
         kfree(__percpu_disguise(__pdata));
 }