Merge with upstream to accommodate with thermal changes

This merge is performed to take commit c56f5c0342dfee11a1 ("Thermal: Make
Thermal trip points writeable") out of Linus' tree and then fixup power
supply class. This is needed since thermal stuff added a new argument:

  CC      drivers/power/power_supply_core.o
drivers/power/power_supply_core.c: In function ‘psy_register_thermal’:
drivers/power/power_supply_core.c:204:6: warning: passing argument 3 of ‘thermal_zone_device_register’ makes integer from pointer without a cast [enabled by default]
include/linux/thermal.h:154:29: note: expected ‘int’ but argument is of type ‘struct power_supply *’
drivers/power/power_supply_core.c:204:6: error: too few arguments to function ‘thermal_zone_device_register’
include/linux/thermal.h:154:29: note: declared here
make[1]: *** [drivers/power/power_supply_core.o] Error 1
make: *** [drivers/power/] Error 2

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

1 files changed, 17 insertions, 13 deletions

diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index 43876f16caf1..cb00ccc7d571 100644
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -47,16 +47,26 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte)
  * they can run pmd_offset_map_lock or pmd_trans_huge or other pmd
  * operations.
  *
- * Without THP if the mmap_sem is hold for reading, the
- * pmd can only transition from null to not null while pmd_read_atomic runs.
- * So there's no need of literally reading it atomically.
+ * Without THP if the mmap_sem is hold for reading, the pmd can only
+ * transition from null to not null while pmd_read_atomic runs. So
+ * we can always return atomic pmd values with this function.
  *
  * With THP if the mmap_sem is hold for reading, the pmd can become
- * THP or null or point to a pte (and in turn become "stable") at any
- * time under pmd_read_atomic, so it's mandatory to read it atomically
- * with cmpxchg8b.
+ * trans_huge or none or point to a pte (and in turn become "stable")
+ * at any time under pmd_read_atomic. We could read it really
+ * atomically here with a atomic64_read for the THP enabled case (and
+ * it would be a whole lot simpler), but to avoid using cmpxchg8b we
+ * only return an atomic pmdval if the low part of the pmdval is later
+ * found stable (i.e. pointing to a pte). And we're returning a none
+ * pmdval if the low part of the pmd is none. In some cases the high
+ * and low part of the pmdval returned may not be consistent if THP is
+ * enabled (the low part may point to previously mapped hugepage,
+ * while the high part may point to a more recently mapped hugepage),
+ * but pmd_none_or_trans_huge_or_clear_bad() only needs the low part
+ * of the pmd to be read atomically to decide if the pmd is unstable
+ * or not, with the only exception of when the low part of the pmd is
+ * zero in which case we return a none pmd.
  */
-#ifndef CONFIG_TRANSPARENT_HUGEPAGE
 static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 {
         pmdval_t ret;
@@ -74,12 +84,6 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 
         return (pmd_t) { ret };
 }
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
-{
-        return (pmd_t) { atomic64_read((atomic64_t *)pmdp) };
-}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
 {