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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-11-21 16:29:40 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-12-18 09:54:38 +0100 |
| commit | 14cf3d977b80f5e355f8ac7547cf1b9ff9fb3e09 (patch) | |
| tree | 26dff7a852d6e5c5f48c55404662c67cd94c604b /arch | |
| parent | 4f9d1382e6f80dcfa891b2c02d5a35c53be485f1 (diff) | |
| download | lwn-14cf3d977b80f5e355f8ac7547cf1b9ff9fb3e09.tar.gz lwn-14cf3d977b80f5e355f8ac7547cf1b9ff9fb3e09.zip | |
x86/gup: Replace ACCESS_ONCE with READ_ONCE
ACCESS_ONCE does not work reliably on non-scalar types. For
example gcc 4.6 and 4.7 might remove the volatile tag for such
accesses during the SRA (scalar replacement of aggregates) step
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145)
Change the gup code to replace ACCESS_ONCE with READ_ONCE.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/gup.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 207d9aef662d..d7547824e763 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -15,7 +15,7 @@ static inline pte_t gup_get_pte(pte_t *ptep) { #ifndef CONFIG_X86_PAE - return ACCESS_ONCE(*ptep); + return READ_ONCE(*ptep); #else /* * With get_user_pages_fast, we walk down the pagetables without taking |