percpu: add __percpu sparse annotations to core kernel subsystems

Add __percpu sparse annotations to core subsystems.

These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors.  This patch doesn't affect normal builds.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-mm@kvack.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biederman <ebiederm@xmission.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index b336638d20e7..768419d44ad7 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -80,13 +80,15 @@
 /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
 #ifndef __addr_to_pcpu_ptr
 #define __addr_to_pcpu_ptr(addr)                                        \
-        (void *)((unsigned long)(addr) - (unsigned long)pcpu_base_addr  \
-                 + (unsigned long)__per_cpu_start)
+        (void __percpu *)((unsigned long)(addr) -                       \
+                          (unsigned long)pcpu_base_addr +               \
+                          (unsigned long)__per_cpu_start)
 #endif
 #ifndef __pcpu_ptr_to_addr
 #define __pcpu_ptr_to_addr(ptr)                                         \
-        (void *)((unsigned long)(ptr) + (unsigned long)pcpu_base_addr   \
-                 - (unsigned long)__per_cpu_start)
+        (void __force *)((unsigned long)(ptr) +                         \
+                         (unsigned long)pcpu_base_addr -                \
+                         (unsigned long)__per_cpu_start)
 #endif
 
 struct pcpu_chunk {
@@ -1065,7 +1067,7 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
  * RETURNS:
  * Percpu pointer to the allocated area on success, NULL on failure.
  */
-static void *pcpu_alloc(size_t size, size_t align, bool reserved)
+static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
 {
         static int warn_limit = 10;
         struct pcpu_chunk *chunk;
@@ -1194,7 +1196,7 @@ fail_unlock_mutex:
  * RETURNS:
  * Percpu pointer to the allocated area on success, NULL on failure.
  */
-void *__alloc_percpu(size_t size, size_t align)
+void __percpu *__alloc_percpu(size_t size, size_t align)
 {
         return pcpu_alloc(size, align, false);
 }
@@ -1215,7 +1217,7 @@ EXPORT_SYMBOL_GPL(__alloc_percpu);
  * RETURNS:
  * Percpu pointer to the allocated area on success, NULL on failure.
  */
-void *__alloc_reserved_percpu(size_t size, size_t align)
+void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
 {
         return pcpu_alloc(size, align, true);
 }
@@ -1267,7 +1269,7 @@ static void pcpu_reclaim(struct work_struct *work)
  * CONTEXT:
  * Can be called from atomic context.
  */
-void free_percpu(void *ptr)
+void free_percpu(void __percpu *ptr)
 {
         void *addr;
         struct pcpu_chunk *chunk;