KVM: MMU: Do not treat ZONE_DEVICE pages as being reserved

[mirror_ubuntu-bionic-kernel.git] / include / linux / gfp.h

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 1a4582b44d3273d41d5e0e65ca38857cee14561e..4bf24c9232b6c2b512a7fe9ce486fd2c93c546b5 100644 (file)
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -308,6 +308,29 @@ static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
        return !!(gfp_flags & __GFP_DIRECT_RECLAIM);
 }
 
+/**
+ * gfpflags_normal_context - is gfp_flags a normal sleepable context?
+ * @gfp_flags: gfp_flags to test
+ *
+ * Test whether @gfp_flags indicates that the allocation is from the
+ * %current context and allowed to sleep.
+ *
+ * An allocation being allowed to block doesn't mean it owns the %current
+ * context.  When direct reclaim path tries to allocate memory, the
+ * allocation context is nested inside whatever %current was doing at the
+ * time of the original allocation.  The nested allocation may be allowed
+ * to block but modifying anything %current owns can corrupt the outer
+ * context's expectations.
+ *
+ * %true result from this function indicates that the allocation context
+ * can sleep and use anything that's associated with %current.
+ */
+static inline bool gfpflags_normal_context(const gfp_t gfp_flags)
+{
+       return (gfp_flags & (__GFP_DIRECT_RECLAIM | __GFP_MEMALLOC)) ==
+               __GFP_DIRECT_RECLAIM;
+}
+
 #ifdef CONFIG_HIGHMEM
 #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
 #else