6 files changed, 52 insertions, 8 deletions

diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index b37300edf27c..07375e73981a 100644
--- a/Documentation/vm/slub.txt
+++ b/Documentation/vm/slub.txt
@@ -41,6 +41,7 @@ Possible debug options are
         P               Poisoning (object and padding)
         U               User tracking (free and alloc)
         T               Trace (please only use on single slabs)
+        A               Toggle failslab filter mark for the cache
         O               Switch debugging off for caches that would have
                         caused higher minimum slab orders
         -               Switch all debugging off (useful if the kernel is
diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index 06ca9b21dad2..7b64ad40e4ce 100644
--- a/include/linux/fault-inject.h
+++ b/include/linux/fault-inject.h
@@ -82,9 +82,10 @@ static inline void cleanup_fault_attr_dentries(struct fault_attr *attr)
 #endif /* CONFIG_FAULT_INJECTION */
 
 #ifdef CONFIG_FAILSLAB
-extern bool should_failslab(size_t size, gfp_t gfpflags);
+extern bool should_failslab(size_t size, gfp_t gfpflags, unsigned long flags);
 #else
-static inline bool should_failslab(size_t size, gfp_t gfpflags)
+static inline bool should_failslab(size_t size, gfp_t gfpflags,
+                                unsigned long flags)
 {
         return false;
 }
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 2da8372519f5..488446289cab 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -70,6 +70,11 @@
 #else
 # define SLAB_NOTRACK           0x00000000UL
 #endif
+#ifdef CONFIG_FAILSLAB
+# define SLAB_FAILSLAB          0x02000000UL    /* Fault injection mark */
+#else
+# define SLAB_FAILSLAB          0x00000000UL
+#endif
 
 /* The following flags affect the page allocator grouping pages by mobility */
 #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
diff --git a/mm/failslab.c b/mm/failslab.c
index 9339de5f0a91..bb41f98dd8b7 100644
--- a/mm/failslab.c
+++ b/mm/failslab.c
@@ -1,18 +1,22 @@
 #include <linux/fault-inject.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
 
 static struct {
         struct fault_attr attr;
         u32 ignore_gfp_wait;
+        int cache_filter;
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
         struct dentry *ignore_gfp_wait_file;
+        struct dentry *cache_filter_file;
 #endif
 } failslab = {
         .attr = FAULT_ATTR_INITIALIZER,
         .ignore_gfp_wait = 1,
+        .cache_filter = 0,
 };
 
-bool should_failslab(size_t size, gfp_t gfpflags)
+bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags)
 {
         if (gfpflags & __GFP_NOFAIL)
                 return false;
@@ -20,6 +24,9 @@ bool should_failslab(size_t size, gfp_t gfpflags)
         if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT))
                 return false;
 
+        if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB))
+                return false;
+
         return should_fail(&failslab.attr, size);
 }
 
@@ -30,7 +37,6 @@ static int __init setup_failslab(char *str)
 __setup("failslab=", setup_failslab);
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
-
 static int __init failslab_debugfs_init(void)
 {
         mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
@@ -46,8 +52,14 @@ static int __init failslab_debugfs_init(void)
                 debugfs_create_bool("ignore-gfp-wait", mode, dir,
                                       &failslab.ignore_gfp_wait);
 
-        if (!failslab.ignore_gfp_wait_file) {
+        failslab.cache_filter_file =
+                debugfs_create_bool("cache-filter", mode, dir,
+                                      &failslab.cache_filter);
+
+        if (!failslab.ignore_gfp_wait_file ||
+            !failslab.cache_filter_file) {
                 err = -ENOMEM;
+                debugfs_remove(failslab.cache_filter_file);
                 debugfs_remove(failslab.ignore_gfp_wait_file);
                 cleanup_fault_attr_dentries(&failslab.attr);
         }
diff --git a/mm/slab.c b/mm/slab.c
index 7451bdacaf18..33496b704859 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3101,7 +3101,7 @@ static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
         if (cachep == &cache_cache)
                 return false;
 
-        return should_failslab(obj_size(cachep), flags);
+        return should_failslab(obj_size(cachep), flags, cachep->flags);
 }
 
 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
diff --git a/mm/slub.c b/mm/slub.c
index 8d71aaf888d7..cab5288736c8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -151,7 +151,8 @@
  * Set of flags that will prevent slab merging
  */
 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
-                SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE)
+                SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
+                SLAB_FAILSLAB)
 
 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
                 SLAB_CACHE_DMA | SLAB_NOTRACK)
@@ -1020,6 +1021,9 @@ static int __init setup_slub_debug(char *str)
                 case 't':
                         slub_debug |= SLAB_TRACE;
                         break;
+                case 'a':
+                        slub_debug |= SLAB_FAILSLAB;
+                        break;
                 default:
                         printk(KERN_ERR "slub_debug option '%c' "
                                 "unknown. skipped\n", *str);
@@ -1718,7 +1722,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
         lockdep_trace_alloc(gfpflags);
         might_sleep_if(gfpflags & __GFP_WAIT);
 
-        if (should_failslab(s->objsize, gfpflags))
+        if (should_failslab(s->objsize, gfpflags, s->flags))
                 return NULL;
 
         local_irq_save(flags);
@@ -4171,6 +4175,23 @@ static ssize_t trace_store(struct kmem_cache *s, const char *buf,
 }
 SLAB_ATTR(trace);
 
+#ifdef CONFIG_FAILSLAB
+static ssize_t failslab_show(struct kmem_cache *s, char *buf)
+{
+        return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
+}
+
+static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
+                                                        size_t length)
+{
+        s->flags &= ~SLAB_FAILSLAB;
+        if (buf[0] == '1')
+                s->flags |= SLAB_FAILSLAB;
+        return length;
+}
+SLAB_ATTR(failslab);
+#endif
+
 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
 {
         return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
@@ -4467,6 +4488,10 @@ static struct attribute *slab_attrs[] = {
         &deactivate_remote_frees_attr.attr,
         &order_fallback_attr.attr,
 #endif
+#ifdef CONFIG_FAILSLAB
+        &failslab_attr.attr,
+#endif
+
         NULL
 };