rt-patches/0201-mm-rt-Fix-generic-kmap_atomic-for-RT.patch

   1 From 6b8e29bf24760f62db2632f70a7aa0cda216a36e Mon Sep 17 00:00:00 2001
   2 From: Thomas Gleixner <tglx@linutronix.de>
   3 Date: Sat, 19 Sep 2015 10:15:00 +0200
   4 Subject: [PATCH 201/366] mm: rt: Fix generic kmap_atomic for RT
   5
   6 The update to 4.1 brought in the mainline variant of the pagefault
   7 disable distangling from preempt count. That introduced a
   8 preempt_disable/enable pair in the generic kmap_atomic/kunmap_atomic
   9 implementations which got not converted to the _nort() variant.
  10
  11 That results in massive 'scheduling while atomic/sleeping function
  12 called from invalid context' splats.
  13
  14 Fix that up.
  15
  16 Reported-and-tested-by: Juergen Borleis <jbe@pengutronix.de>
  17 Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  18 ---
  19  include/linux/highmem.h | 4 ++--
  20  1 file changed, 2 insertions(+), 2 deletions(-)
  21
  22 diff --git a/include/linux/highmem.h b/include/linux/highmem.h
  23 index 396d5c4..2f56829 100644
  24 --- a/include/linux/highmem.h
  25 +++ b/include/linux/highmem.h
  26 @@ -65,7 +65,7 @@ static inline void kunmap(struct page *page)
  27
  28  static inline void *kmap_atomic(struct page *page)
  29  {
  30 -       preempt_disable();
  31 +       preempt_disable_nort();
  32         pagefault_disable();
  33         return page_address(page);
  34  }
  35 @@ -74,7 +74,7 @@ static inline void *kmap_atomic(struct page *page)
  36  static inline void __kunmap_atomic(void *addr)
  37  {
  38         pagefault_enable();
  39 -       preempt_enable();
  40 +       preempt_enable_nort();
  41  }
  42
  43  #define kmap_atomic_pfn(pfn)   kmap_atomic(pfn_to_page(pfn))
  44 --
  45 1.9.1
  46