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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-05 08:25:34 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-05 08:25:34 -0700
commit6fbfd0592ef88ba29cdce84ef92757351f1fa9c9 (patch)
tree7c0af4bcc08f3ad7befb93d73d9729f82252c950 /include/asm-generic/pgtable.h
parentf2c32a882d2c1cde6fc552a5a3d34b4c1330edb8 (diff)
parent6887a4131da3adaab011613776d865f4bcfb5678 (diff)
downloadop-kernel-dev-6fbfd0592ef88ba29cdce84ef92757351f1fa9c9.zip
op-kernel-dev-6fbfd0592ef88ba29cdce84ef92757351f1fa9c9.tar.gz
Merge v3.5-rc5 into driver-core-next
This picks up the big printk fixes, and resolves a merge issue with: drivers/extcon/extcon_gpio.c Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/asm-generic/pgtable.h')
-rw-r--r--include/asm-generic/pgtable.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 6f2b45a..ff4947b 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -484,6 +484,16 @@ static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
/*
* The barrier will stabilize the pmdval in a register or on
* the stack so that it will stop changing under the code.
+ *
+ * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
+ * pmd_read_atomic is allowed to return a not atomic pmdval
+ * (for example pointing to an hugepage that has never been
+ * mapped in the pmd). The below checks will only care about
+ * the low part of the pmd with 32bit PAE x86 anyway, with the
+ * exception of pmd_none(). So the important thing is that if
+ * the low part of the pmd is found null, the high part will
+ * be also null or the pmd_none() check below would be
+ * confused.
*/
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
barrier();
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