[PATCH v4 1/3] mm: slab/slub: Add check_slab_flags function to check for valid flags

Nicolas Boichat
2018-12-05T05:49:30Z

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 <drinkcat@chromium.org>
---
mm/internal.h | 18 ++++++++++++++++--
mm/slab.c | 8 +-------
mm/slub.c | 8 +-------
3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index f0c9ccde3bdb9e..a2ee82a0cd44ae 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 73fe23e649c91a..65a774f05e7836 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2643,13 +2643,7 @@ 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 c229a9b7dd5448..21a3f6866da472 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1685,13 +1685,7 @@ 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);
--
2.20.0.rc1.387.gf8505762e3-goog