Thread (35 messages) 35 messages, 8 authors, 2018-12-05
STALE2774d
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[PATCH v2 1/3] mm: slab/slub: Add check_slab_flags function to check for valid flags

From: Nicolas Boichat <hidden>
Date: 2018-11-11 09:04:14
Also in: linux-iommu, linux-mm, lkml
Subsystem: memory management, memory management - core, slab allocator, the rest · Maintainers: Andrew Morton, David Hildenbrand, Vlastimil Babka, Harry Yoo, Linus Torvalds

Remove duplicated code between slab and slub, and will make it
easier to make the test more complicated in the next commits.

Fixes: ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32")
Signed-off-by: Nicolas Boichat <redacted>
---
 mm/internal.h | 17 +++++++++++++++--
 mm/slab.c     |  8 +-------
 mm/slub.c     |  8 +-------
 3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/mm/internal.h b/mm/internal.h
index 3b1ec1412fd2cd..7a500b232e4a43 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -33,8 +33,22 @@
 /* Control allocation cpuset and node placement constraints */
 #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
 
-/* Do not use these with a slab allocator */
-#define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
+/* Check for flags that must not be used with a slab allocator */
+static inline gfp_t check_slab_flags(gfp_t flags)
+{
+	gfp_t bug_mask = __GFP_DMA32 | __GFP_HIGHMEM | ~__GFP_BITS_MASK;
+
+	if (unlikely(flags & bug_mask)) {
+		gfp_t invalid_mask = flags & bug_mask;
+
+		flags &= ~bug_mask;
+		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+				invalid_mask, &invalid_mask, flags, &flags);
+		dump_stack();
+	}
+
+	return flags;
+}
 
 void page_writeback_init(void);
 
diff --git a/mm/slab.c b/mm/slab.c
index 2a5654bb3b3ff3..251e09a5a3ef5c 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2656,13 +2656,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	 * Be lazy and only check for valid flags here,  keeping it out of the
 	 * critical path in kmem_cache_alloc().
 	 */
-	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
-		gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
-		flags &= ~GFP_SLAB_BUG_MASK;
-		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
-				invalid_mask, &invalid_mask, flags, &flags);
-		dump_stack();
-	}
+	flags = check_slab_flags(flags);
 	WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
 	local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
 
diff --git a/mm/slub.c b/mm/slub.c
index e3629cd7aff164..1cca562bebdc8d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1681,13 +1681,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
-	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
-		gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
-		flags &= ~GFP_SLAB_BUG_MASK;
-		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
-				invalid_mask, &invalid_mask, flags, &flags);
-		dump_stack();
-	}
+	flags = check_slab_flags(flags);
 
 	return allocate_slab(s,
 		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
-- 
2.19.1.930.g4563a0d9d0-goog
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