mips/gup: Replace ACCESS_ONCE with READ_ONCE

borntraeger · borntraeger · commit 4218091cb45f · 2014-12-18T09:54:39.000+01:00
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>
diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c
@@ -30,7 +30,7 @@ static inline pte_t gup_get_pte(pte_t *ptep)
 
 	return pte;
 #else
-	return ACCESS_ONCE(*ptep);
+	return READ_ONCE(*ptep);
 #endif
 }
 

Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,7 @@ static inline pte_t gup_get_pte(pte_t *ptep)`
`30`	`30`
`31`	`31`	`return pte;`
`32`	`32`	`#else`
`33`		`- return ACCESS_ONCE(*ptep);`
	`33`	`+ return READ_ONCE(*ptep);`
`34`	`34`	`#endif`
`35`	`35`	`}`
`36`	`36`