Merge tag 'v3.6-rc2' into drm-intel-next

Backmerge Linux 3.6-rc2 to resolve a few funny conflicts before we put
even more madness on top:

- drivers/gpu/drm/i915/i915_irq.c: Just a spurious WARN removed in
  -fixes, that has been changed in a variable-rename in -next, too.

- drivers/gpu/drm/i915/intel_ringbuffer.c: -next remove scratch_addr
  (since all their users have been extracted in another fucntion),
  -fixes added another user for a hw workaroudn.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 140 insertions, 58 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d78671e9d54..fe00d120816 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -145,6 +145,43 @@ static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
 	BUG();
 }
 
+
+/*
+ * kmalloc_reserve is a wrapper around kmalloc_node_track_caller that tells
+ * the caller if emergency pfmemalloc reserves are being used. If it is and
+ * the socket is later found to be SOCK_MEMALLOC then PFMEMALLOC reserves
+ * may be used. Otherwise, the packet data may be discarded until enough
+ * memory is free
+ */
+#define kmalloc_reserve(size, gfp, node, pfmemalloc) \
+	 __kmalloc_reserve(size, gfp, node, _RET_IP_, pfmemalloc)
+void *__kmalloc_reserve(size_t size, gfp_t flags, int node, unsigned long ip,
+			 bool *pfmemalloc)
+{
+	void *obj;
+	bool ret_pfmemalloc = false;
+
+	/*
+	 * Try a regular allocation, when that fails and we're not entitled
+	 * to the reserves, fail.
+	 */
+	obj = kmalloc_node_track_caller(size,
+					flags | __GFP_NOMEMALLOC | __GFP_NOWARN,
+					node);
+	if (obj || !(gfp_pfmemalloc_allowed(flags)))
+		goto out;
+
+	/* Try again but now we are using pfmemalloc reserves */
+	ret_pfmemalloc = true;
+	obj = kmalloc_node_track_caller(size, flags, node);
+
+out:
+	if (pfmemalloc)
+		*pfmemalloc = ret_pfmemalloc;
+
+	return obj;
+}
+
 /* 	Allocate a new skbuff. We do this ourselves so we can fill in a few
  *	'private' fields and also do memory statistics to find all the
  *	[BEEP] leaks.
@@ -155,26 +192,33 @@ static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
  *	__alloc_skb	-	allocate a network buffer
  *	@size: size to allocate
  *	@gfp_mask: allocation mask
- *	@fclone: allocate from fclone cache instead of head cache
- *		and allocate a cloned (child) skb
+ *	@flags: If SKB_ALLOC_FCLONE is set, allocate from fclone cache
+ *		instead of head cache and allocate a cloned (child) skb.
+ *		If SKB_ALLOC_RX is set, __GFP_MEMALLOC will be used for
+ *		allocations in case the data is required for writeback
  *	@node: numa node to allocate memory on
  *
  *	Allocate a new &sk_buff. The returned buffer has no headroom and a
- *	tail room of size bytes. The object has a reference count of one.
- *	The return is the buffer. On a failure the return is %NULL.
+ *	tail room of at least size bytes. The object has a reference count
+ *	of one. The return is the buffer. On a failure the return is %NULL.
  *
  *	Buffers may only be allocated from interrupts using a @gfp_mask of
  *	%GFP_ATOMIC.
  */
 struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
-			    int fclone, int node)
+			    int flags, int node)
 {
 	struct kmem_cache *cache;
 	struct skb_shared_info *shinfo;
 	struct sk_buff *skb;
 	u8 *data;
+	bool pfmemalloc;
 
-	cache = fclone ? skbuff_fclone_cache : skbuff_head_cache;
+	cache = (flags & SKB_ALLOC_FCLONE)
+		? skbuff_fclone_cache : skbuff_head_cache;
+
+	if (sk_memalloc_socks() && (flags & SKB_ALLOC_RX))
+		gfp_mask |= __GFP_MEMALLOC;
 
 	/* Get the HEAD */
 	skb = kmem_cache_alloc_node(cache, gfp_mask & ~__GFP_DMA, node);
@@ -189,7 +233,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	 */
 	size = SKB_DATA_ALIGN(size);
 	size += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
-	data = kmalloc_node_track_caller(size, gfp_mask, node);
+	data = kmalloc_reserve(size, gfp_mask, node, &pfmemalloc);
 	if (!data)
 		goto nodata;
 	/* kmalloc(size) might give us more room than requested.
@@ -207,6 +251,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	memset(skb, 0, offsetof(struct sk_buff, tail));
 	/* Account for allocated memory : skb + skb->head */
 	skb->truesize = SKB_TRUESIZE(size);
+	skb->pfmemalloc = pfmemalloc;
 	atomic_set(&skb->users, 1);
 	skb->head = data;
 	skb->data = data;
@@ -222,7 +267,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	atomic_set(&shinfo->dataref, 1);
 	kmemcheck_annotate_variable(shinfo->destructor_arg);
 
-	if (fclone) {
+	if (flags & SKB_ALLOC_FCLONE) {
 		struct sk_buff *child = skb + 1;
 		atomic_t *fclone_ref = (atomic_t *) (child + 1);
 
@@ -232,6 +277,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 		atomic_set(fclone_ref, 1);
 
 		child->fclone = SKB_FCLONE_UNAVAILABLE;
+		child->pfmemalloc = pfmemalloc;
 	}
 out:
 	return skb;
@@ -296,17 +342,13 @@ EXPORT_SYMBOL(build_skb);
 struct netdev_alloc_cache {
 	struct page *page;
 	unsigned int offset;
+	unsigned int pagecnt_bias;
 };
 static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
 
-/**
- * netdev_alloc_frag - allocate a page fragment
- * @fragsz: fragment size
- *
- * Allocates a frag from a page for receive buffer.
- * Uses GFP_ATOMIC allocations.
- */
-void *netdev_alloc_frag(unsigned int fragsz)
+#define NETDEV_PAGECNT_BIAS (PAGE_SIZE / SMP_CACHE_BYTES)
+
+static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
 {
 	struct netdev_alloc_cache *nc;
 	void *data = NULL;
@@ -316,21 +358,42 @@ void *netdev_alloc_frag(unsigned int fragsz)
 	nc = &__get_cpu_var(netdev_alloc_cache);
 	if (unlikely(!nc->page)) {
 refill:
-		nc->page = alloc_page(GFP_ATOMIC | __GFP_COLD);
+		nc->page = alloc_page(gfp_mask);
+		if (unlikely(!nc->page))
+			goto end;
+recycle:
+		atomic_set(&nc->page->_count, NETDEV_PAGECNT_BIAS);
+		nc->pagecnt_bias = NETDEV_PAGECNT_BIAS;
 		nc->offset = 0;
 	}
-	if (likely(nc->page)) {
-		if (nc->offset + fragsz > PAGE_SIZE) {
-			put_page(nc->page);
-			goto refill;
-		}
-		data = page_address(nc->page) + nc->offset;
-		nc->offset += fragsz;
-		get_page(nc->page);
+
+	if (nc->offset + fragsz > PAGE_SIZE) {
+		/* avoid unnecessary locked operations if possible */
+		if ((atomic_read(&nc->page->_count) == nc->pagecnt_bias) ||
+		    atomic_sub_and_test(nc->pagecnt_bias, &nc->page->_count))
+			goto recycle;
+		goto refill;
 	}
+
+	data = page_address(nc->page) + nc->offset;
+	nc->offset += fragsz;
+	nc->pagecnt_bias--;
+end:
 	local_irq_restore(flags);
 	return data;
 }
+
+/**
+ * netdev_alloc_frag - allocate a page fragment
+ * @fragsz: fragment size
+ *
+ * Allocates a frag from a page for receive buffer.
+ * Uses GFP_ATOMIC allocations.
+ */
+void *netdev_alloc_frag(unsigned int fragsz)
+{
+	return __netdev_alloc_frag(fragsz, GFP_ATOMIC | __GFP_COLD);
+}
 EXPORT_SYMBOL(netdev_alloc_frag);
 
 /**
@@ -353,8 +416,13 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
 	unsigned int fragsz = SKB_DATA_ALIGN(length + NET_SKB_PAD) +
 			      SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
-	if (fragsz <= PAGE_SIZE && !(gfp_mask & __GFP_WAIT)) {
-		void *data = netdev_alloc_frag(fragsz);
+	if (fragsz <= PAGE_SIZE && !(gfp_mask & (__GFP_WAIT | GFP_DMA))) {
+		void *data;
+
+		if (sk_memalloc_socks())
+			gfp_mask |= __GFP_MEMALLOC;
+
+		data = __netdev_alloc_frag(fragsz, gfp_mask);
 
 		if (likely(data)) {
 			skb = build_skb(data, fragsz);
@@ -362,7 +430,8 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
 				put_page(virt_to_head_page(data));
 		}
 	} else {
-		skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, NUMA_NO_NODE);
+		skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask,
+				  SKB_ALLOC_RX, NUMA_NO_NODE);
 	}
 	if (likely(skb)) {
 		skb_reserve(skb, NET_SKB_PAD);
@@ -644,6 +713,7 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 #if IS_ENABLED(CONFIG_IP_VS)
 	new->ipvs_property	= old->ipvs_property;
 #endif
+	new->pfmemalloc		= old->pfmemalloc;
 	new->protocol		= old->protocol;
 	new->mark		= old->mark;
 	new->skb_iif		= old->skb_iif;
@@ -713,7 +783,8 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
 }
 EXPORT_SYMBOL_GPL(skb_morph);
 
-/*	skb_copy_ubufs	-	copy userspace skb frags buffers to kernel
+/**
+ *	skb_copy_ubufs	-	copy userspace skb frags buffers to kernel
  *	@skb: the skb to modify
  *	@gfp_mask: allocation priority
  *
@@ -738,7 +809,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 		u8 *vaddr;
 		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 
-		page = alloc_page(GFP_ATOMIC);
+		page = alloc_page(gfp_mask);
 		if (!page) {
 			while (head) {
 				struct page *next = (struct page *)head->private;
@@ -756,22 +827,22 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 	}
 
 	/* skb frags release userspace buffers */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+	for (i = 0; i < num_frags; i++)
 		skb_frag_unref(skb, i);
 
 	uarg->callback(uarg);
 
 	/* skb frags point to kernel buffers */
-	for (i = skb_shinfo(skb)->nr_frags; i > 0; i--) {
-		__skb_fill_page_desc(skb, i-1, head, 0,
-				     skb_shinfo(skb)->frags[i - 1].size);
+	for (i = num_frags - 1; i >= 0; i--) {
+		__skb_fill_page_desc(skb, i, head, 0,
+				     skb_shinfo(skb)->frags[i].size);
 		head = (struct page *)head->private;
 	}
 
 	skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
 	return 0;
 }
-
+EXPORT_SYMBOL_GPL(skb_copy_ubufs);
 
 /**
  *	skb_clone	-	duplicate an sk_buff
@@ -791,10 +862,8 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 {
 	struct sk_buff *n;
 
-	if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
-		if (skb_copy_ubufs(skb, gfp_mask))
-			return NULL;
-	}
+	if (skb_orphan_frags(skb, gfp_mask))
+		return NULL;
 
 	n = skb + 1;
 	if (skb->fclone == SKB_FCLONE_ORIG &&
@@ -803,6 +872,9 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 		n->fclone = SKB_FCLONE_CLONE;
 		atomic_inc(fclone_ref);
 	} else {
+		if (skb_pfmemalloc(skb))
+			gfp_mask |= __GFP_MEMALLOC;
+
 		n = kmem_cache_alloc(skbuff_head_cache, gfp_mask);
 		if (!n)
 			return NULL;
@@ -839,6 +911,13 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	skb_shinfo(new)->gso_type = skb_shinfo(old)->gso_type;
 }
 
+static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
+{
+	if (skb_pfmemalloc(skb))
+		return SKB_ALLOC_RX;
+	return 0;
+}
+
 /**
  *	skb_copy	-	create private copy of an sk_buff
  *	@skb: buffer to copy
@@ -860,7 +939,8 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 {
 	int headerlen = skb_headroom(skb);
 	unsigned int size = skb_end_offset(skb) + skb->data_len;
-	struct sk_buff *n = alloc_skb(size, gfp_mask);
+	struct sk_buff *n = __alloc_skb(size, gfp_mask,
+					skb_alloc_rx_flag(skb), NUMA_NO_NODE);
 
 	if (!n)
 		return NULL;
@@ -895,7 +975,8 @@ EXPORT_SYMBOL(skb_copy);
 struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
 {
 	unsigned int size = skb_headlen(skb) + headroom;
-	struct sk_buff *n = alloc_skb(size, gfp_mask);
+	struct sk_buff *n = __alloc_skb(size, gfp_mask,
+					skb_alloc_rx_flag(skb), NUMA_NO_NODE);
 
 	if (!n)
 		goto out;
@@ -914,12 +995,10 @@ struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
 	if (skb_shinfo(skb)->nr_frags) {
 		int i;
 
-		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
-			if (skb_copy_ubufs(skb, gfp_mask)) {
-				kfree_skb(n);
-				n = NULL;
-				goto out;
-			}
+		if (skb_orphan_frags(skb, gfp_mask)) {
+			kfree_skb(n);
+			n = NULL;
+			goto out;
 		}
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 			skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
@@ -970,8 +1049,10 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 
 	size = SKB_DATA_ALIGN(size);
 
-	data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
-		       gfp_mask);
+	if (skb_pfmemalloc(skb))
+		gfp_mask |= __GFP_MEMALLOC;
+	data = kmalloc_reserve(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+			       gfp_mask, NUMA_NO_NODE, NULL);
 	if (!data)
 		goto nodata;
 	size = SKB_WITH_OVERHEAD(ksize(data));
@@ -992,10 +1073,8 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 	 */
 	if (skb_cloned(skb)) {
 		/* copy this zero copy skb frags */
-		if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
-			if (skb_copy_ubufs(skb, gfp_mask))
-				goto nofrags;
-		}
+		if (skb_orphan_frags(skb, gfp_mask))
+			goto nofrags;
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 			skb_frag_ref(skb, i);
 
@@ -1085,8 +1164,9 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
 	/*
 	 *	Allocate the copy buffer
 	 */
-	struct sk_buff *n = alloc_skb(newheadroom + skb->len + newtailroom,
-				      gfp_mask);
+	struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
+					gfp_mask, skb_alloc_rx_flag(skb),
+					NUMA_NO_NODE);
 	int oldheadroom = skb_headroom(skb);
 	int head_copy_len, head_copy_off;
 	int off;
@@ -1755,6 +1835,7 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
 	struct splice_pipe_desc spd = {
 		.pages = pages,
 		.partial = partial,
+		.nr_pages_max = MAX_SKB_FRAGS,
 		.flags = flags,
 		.ops = &sock_pipe_buf_ops,
 		.spd_release = sock_spd_release,
@@ -2613,7 +2694,7 @@ unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
 EXPORT_SYMBOL(skb_find_text);
 
 /**
- * skb_append_datato_frags: - append the user data to a skb
+ * skb_append_datato_frags - append the user data to a skb
  * @sk: sock  structure
  * @skb: skb structure to be appened with user data.
  * @getfrag: call back function to be used for getting the user data
@@ -2767,8 +2848,9 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 			skb_release_head_state(nskb);
 			__skb_push(nskb, doffset);
 		} else {
-			nskb = alloc_skb(hsize + doffset + headroom,
-					 GFP_ATOMIC);
+			nskb = __alloc_skb(hsize + doffset + headroom,
+					   GFP_ATOMIC, skb_alloc_rx_flag(skb),
+					   NUMA_NO_NODE);
 
 			if (unlikely(!nskb))
 				goto err;