slub: Remove dynamic dma slab allocation

Remove the dynamic dma slab allocation since this causes too many issues with
nested locks etc etc. The change avoids passing gfpflags into many functions.

V3->V4:
- Create dma caches in kmem_cache_init() instead of kmem_cache_init_late().

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -2064,7 +2064,7 @@ init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
 
 static DEFINE_PER_CPU(struct kmem_cache_cpu, kmalloc_percpu[KMALLOC_CACHES]);
 
-static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
+static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
 {
 	if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
 		/*
@@ -2091,7 +2091,7 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
  * when allocating for the kmalloc_node_cache. This is used for bootstrapping
  * memory on a fresh node that has no slab structures yet.
  */
-static void early_kmem_cache_node_alloc(gfp_t gfpflags, int node)
+static void early_kmem_cache_node_alloc(int node)
 {
 	struct page *page;
 	struct kmem_cache_node *n;
@@ -2099,7 +2099,7 @@ static void early_kmem_cache_node_alloc(gfp_t gfpflags, int node)
 
 	BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node));
 
-	page = new_slab(kmalloc_caches, gfpflags, node);
+	page = new_slab(kmalloc_caches, GFP_NOWAIT, node);
 
 	BUG_ON(!page);
 	if (page_to_nid(page) != node) {
@@ -2143,7 +2143,7 @@ static void free_kmem_cache_nodes(struct kmem_cache *s)
 	}
 }
 
-static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
+static int init_kmem_cache_nodes(struct kmem_cache *s)
 {
 	int node;
 
@@ -2151,11 +2151,11 @@ static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
 		struct kmem_cache_node *n;
 
 		if (slab_state == DOWN) {
-			early_kmem_cache_node_alloc(gfpflags, node);
+			early_kmem_cache_node_alloc(node);
 			continue;
 		}
 		n = kmem_cache_alloc_node(kmalloc_caches,
-						gfpflags, node);
+						GFP_KERNEL, node);
 
 		if (!n) {
 			free_kmem_cache_nodes(s);
@@ -2172,7 +2172,7 @@ static void free_kmem_cache_nodes(struct kmem_cache *s)
 {
 }
 
-static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
+static int init_kmem_cache_nodes(struct kmem_cache *s)
 {
 	init_kmem_cache_node(&s->local_node, s);
 	return 1;
@@ -2312,7 +2312,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 
 }
 
-static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
+static int kmem_cache_open(struct kmem_cache *s,
 		const char *name, size_t size,
 		size_t align, unsigned long flags,
 		void (*ctor)(void *))
@@ -2348,10 +2348,10 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
 #ifdef CONFIG_NUMA
 	s->remote_node_defrag_ratio = 1000;
 #endif
-	if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
+	if (!init_kmem_cache_nodes(s))
 		goto error;
 
-	if (alloc_kmem_cache_cpus(s, gfpflags & ~SLUB_DMA))
+	if (alloc_kmem_cache_cpus(s))
 		return 1;
 
 	free_kmem_cache_nodes(s);
@@ -2510,6 +2510,10 @@ EXPORT_SYMBOL(kmem_cache_destroy);
 struct kmem_cache kmalloc_caches[KMALLOC_CACHES] __cacheline_aligned;
 EXPORT_SYMBOL(kmalloc_caches);
 
+#ifdef CONFIG_ZONE_DMA
+static struct kmem_cache kmalloc_dma_caches[SLUB_PAGE_SHIFT];
+#endif
+
 static int __init setup_slub_min_order(char *str)
 {
 	get_option(&str, &slub_min_order);
@@ -2546,116 +2550,26 @@ static int __init setup_slub_nomerge(char *str)
 
 __setup("slub_nomerge", setup_slub_nomerge);
 
-static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
-		const char *name, int size, gfp_t gfp_flags)
+static void create_kmalloc_cache(struct kmem_cache *s,
+		const char *name, int size, unsigned int flags)
 {
-	unsigned int flags = 0;
-
-	if (gfp_flags & SLUB_DMA)
-		flags = SLAB_CACHE_DMA;
-
 	/*
 	 * This function is called with IRQs disabled during early-boot on
 	 * single CPU so there's no need to take slub_lock here.
 	 */
-	if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
+	if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
 								flags, NULL))
 		goto panic;
 
 	list_add(&s->list, &slab_caches);
 
-	if (sysfs_slab_add(s))
-		goto panic;
-	return s;
+	if (!sysfs_slab_add(s))
+		return;
 
 panic:
 	panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
 }
 
-#ifdef CONFIG_ZONE_DMA
-static struct kmem_cache *kmalloc_caches_dma[SLUB_PAGE_SHIFT];
-
-static void sysfs_add_func(struct work_struct *w)
-{
-	struct kmem_cache *s;
-
-	down_write(&slub_lock);
-	list_for_each_entry(s, &slab_caches, list) {
-		if (s->flags & __SYSFS_ADD_DEFERRED) {
-			s->flags &= ~__SYSFS_ADD_DEFERRED;
-			sysfs_slab_add(s);
-		}
-	}
-	up_write(&slub_lock);
-}
-
-static DECLARE_WORK(sysfs_add_work, sysfs_add_func);
-
-static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
-{
-	struct kmem_cache *s;
-	char *text;
-	size_t realsize;
-	unsigned long slabflags;
-	int i;
-
-	s = kmalloc_caches_dma[index];
-	if (s)
-		return s;
-
-	/* Dynamically create dma cache */
-	if (flags & __GFP_WAIT)
-		down_write(&slub_lock);
-	else {
-		if (!down_write_trylock(&slub_lock))
-			goto out;
-	}
-
-	if (kmalloc_caches_dma[index])
-		goto unlock_out;
-
-	realsize = kmalloc_caches[index].objsize;
-	text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
-			 (unsigned int)realsize);
-
-	s = NULL;
-	for (i = 0; i < KMALLOC_CACHES; i++)
-		if (!kmalloc_caches[i].size)
-			break;
-
-	BUG_ON(i >= KMALLOC_CACHES);
-	s = kmalloc_caches + i;
-
-	/*
-	 * Must defer sysfs creation to a workqueue because we don't know
-	 * what context we are called from. Before sysfs comes up, we don't
-	 * need to do anything because our sysfs initcall will start by
-	 * adding all existing slabs to sysfs.
-	 */
-	slabflags = SLAB_CACHE_DMA|SLAB_NOTRACK;
-	if (slab_state >= SYSFS)
-		slabflags |= __SYSFS_ADD_DEFERRED;
-
-	if (!text || !kmem_cache_open(s, flags, text,
-			realsize, ARCH_KMALLOC_MINALIGN, slabflags, NULL)) {
-		s->size = 0;
-		kfree(text);
-		goto unlock_out;
-	}
-
-	list_add(&s->list, &slab_caches);
-	kmalloc_caches_dma[index] = s;
-
-	if (slab_state >= SYSFS)
-		schedule_work(&sysfs_add_work);
-
-unlock_out:
-	up_write(&slub_lock);
-out:
-	return kmalloc_caches_dma[index];
-}
-#endif
-
 /*
  * Conversion table for small slabs sizes / 8 to the index in the
  * kmalloc array. This is necessary for slabs < 192 since we have non power
@@ -2708,7 +2622,7 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags)
 
 #ifdef CONFIG_ZONE_DMA
 	if (unlikely((flags & SLUB_DMA)))
-		return dma_kmalloc_cache(index, flags);
+		return &kmalloc_dma_caches[index];
 
 #endif
 	return &kmalloc_caches[index];
@@ -3047,7 +2961,7 @@ void __init kmem_cache_init(void)
 	 * kmem_cache_open for slab_state == DOWN.
 	 */
 	create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node",
-		sizeof(struct kmem_cache_node), GFP_NOWAIT);
+		sizeof(struct kmem_cache_node), 0);
 	kmalloc_caches[0].refcount = -1;
 	caches++;
 
@@ -3060,18 +2974,18 @@ void __init kmem_cache_init(void)
 	/* Caches that are not of the two-to-the-power-of size */
 	if (KMALLOC_MIN_SIZE <= 32) {
 		create_kmalloc_cache(&kmalloc_caches[1],
-				"kmalloc-96", 96, GFP_NOWAIT);
+				"kmalloc-96", 96, 0);
 		caches++;
 	}
 	if (KMALLOC_MIN_SIZE <= 64) {
 		create_kmalloc_cache(&kmalloc_caches[2],
-				"kmalloc-192", 192, GFP_NOWAIT);
+				"kmalloc-192", 192, 0);
 		caches++;
 	}
 
 	for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
 		create_kmalloc_cache(&kmalloc_caches[i],
-			"kmalloc", 1 << i, GFP_NOWAIT);
+			"kmalloc", 1 << i, 0);
 		caches++;
 	}
 
@@ -3134,6 +3048,20 @@ void __init kmem_cache_init(void)
 	kmem_size = sizeof(struct kmem_cache);
 #endif
 
+#ifdef CONFIG_ZONE_DMA
+	for (i = 1; i < SLUB_PAGE_SHIFT; i++) {
+		struct kmem_cache *s = &kmalloc_caches[i];
+
+		if (s->size) {
+			char *name = kasprintf(GFP_NOWAIT,
+				 "dma-kmalloc-%d", s->objsize);
+
+			BUG_ON(!name);
+			create_kmalloc_cache(&kmalloc_dma_caches[i],
+				name, s->objsize, SLAB_CACHE_DMA);
+		}
+	}
+#endif
 	printk(KERN_INFO
 		"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
 		" CPUs=%d, Nodes=%d\n",
@@ -3236,7 +3164,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 
 	s = kmalloc(kmem_size, GFP_KERNEL);
 	if (s) {
-		if (kmem_cache_open(s, GFP_KERNEL, name,
+		if (kmem_cache_open(s, name,
 				size, align, flags, ctor)) {
 			list_add(&s->list, &slab_caches);
 			if (sysfs_slab_add(s)) {