Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: don't assume existence of cpu0

1 files changed, 14 insertions, 1 deletions

diff --git a/mm/percpu.c b/mm/percpu.c
index 5fe37842e0ea..3311c8919f37 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -197,7 +197,12 @@ static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
 static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
                                      int page_idx)
 {
-        return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
+        /*
+         * Any possible cpu id can be used here, so there's no need to
+         * worry about preemption or cpu hotplug.
+         */
+        return *pcpu_chunk_pagep(chunk, raw_smp_processor_id(),
+                                 page_idx) != NULL;
 }
 
 /* set the pointer to a chunk in a page struct */
@@ -297,6 +302,14 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
                 return pcpu_first_chunk;
         }
 
+        /*
+         * The address is relative to unit0 which might be unused and
+         * thus unmapped.  Offset the address to the unit space of the
+         * current processor before looking it up in the vmalloc
+         * space.  Note that any possible cpu id can be used here, so
+         * there's no need to worry about preemption or cpu hotplug.
+         */
+        addr += raw_smp_processor_id() * pcpu_unit_size;
         return pcpu_get_page_chunk(vmalloc_to_page(addr));
 }