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-rw-r--r--arch/x86/include/asm/uaccess_64.h16
1 files changed, 14 insertions, 2 deletions
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index 84210c479fc..987a2c10fe2 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -192,14 +192,26 @@ static inline int __copy_from_user_nocache(void *dst, const void __user *src,
unsigned size)
{
might_sleep();
- return __copy_user_nocache(dst, src, size, 1);
+ /*
+ * In practice this limit means that large file write()s
+ * which get chunked to 4K copies get handled via
+ * non-temporal stores here. Smaller writes get handled
+ * via regular __copy_from_user():
+ */
+ if (likely(size >= PAGE_SIZE))
+ return __copy_user_nocache(dst, src, size, 1);
+ else
+ return __copy_from_user(dst, src, size);
}
static inline int __copy_from_user_inatomic_nocache(void *dst,
const void __user *src,
unsigned size)
{
- return __copy_user_nocache(dst, src, size, 0);
+ if (likely(size >= PAGE_SIZE))
+ return __copy_user_nocache(dst, src, size, 0);
+ else
+ return __copy_from_user_inatomic(dst, src, size);
}
unsigned long