Patchwork [1/4] net: convert core to skb paged frag APIs

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Submitter Ian Campbell
Date Aug. 23, 2011, 9:44 a.m.
Message ID <1314092701-4347-1-git-send-email-ian.campbell@citrix.com>
Download mbox | patch
Permalink /patch/111069/
State Accepted
Delegated to: David Miller
Headers show

Comments

Ian Campbell - Aug. 23, 2011, 9:44 a.m.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: netdev@vger.kernel.org
---
 include/linux/skbuff.h |    4 ++--
 net/core/datagram.c    |    8 ++++----
 net/core/dev.c         |   16 +++++++++-------
 net/core/kmap_skb.h    |    2 +-
 net/core/pktgen.c      |    3 +--
 net/core/skbuff.c      |   29 +++++++++++++++--------------
 net/core/sock.c        |   12 +++++-------
 net/core/user_dma.c    |    2 +-
 8 files changed, 38 insertions(+), 38 deletions(-)
=?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= - Aug. 23, 2011, 6:34 p.m.
2011/8/23 Ian Campbell <ian.campbell@citrix.com>:
> +               for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
> +                       skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

This is a rather common construct, so it might be worth it to
introduce something like for_each_skb_frag().

Best Regards,
Michał Mirosław
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Ian Campbell - Aug. 24, 2011, 7:49 a.m.
On Tue, 2011-08-23 at 19:34 +0100, Michał Mirosław wrote:
> 2011/8/23 Ian Campbell <ian.campbell@citrix.com>:
> > +               for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
> > +                       skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
> 
> This is a rather common construct, so it might be worth it to
> introduce something like for_each_skb_frag().

I agree. My first stab at this helper (which was untenable for other
reasons, I never posted it) had such a helper. I decided not to tackle
it on this pass since it touches a bunch of places which even this
enormous series doesn't. I've got it on my list to do some time after
this series as a cleanup though.

Some places want the frag nr and others want the skb_frag_t* so I think
you'd end up with
	for_each_skb_frag(skb, frag) { ... }
and
	for_each_skb_frag_nr(skb, i) { ... }
a few places use both frag and i within the loop but not enough to
warrant an explicit helper, I don't think.

An "skb_frag(skb, i)" helper for the &skb_shinfo(skb)->frags[i]
construct might be nice too.

Ian.

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David Miller - Aug. 25, 2011, 12:52 a.m.
From: Ian Campbell <ian.campbell@citrix.com>
Date: Tue, 23 Aug 2011 10:44:58 +0100

> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

Applied.
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Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7b0e177..8d42628 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1898,12 +1898,12 @@  static inline int skb_add_data(struct sk_buff *skb,
 }
 
 static inline int skb_can_coalesce(struct sk_buff *skb, int i,
-				   struct page *page, int off)
+				   const struct page *page, int off)
 {
 	if (i) {
 		struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
 
-		return page == frag->page &&
+		return page == skb_frag_page(frag) &&
 		       off == frag->page_offset + frag->size;
 	}
 	return 0;
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 18ac112..6449bed 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -332,7 +332,7 @@  int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
 			int err;
 			u8  *vaddr;
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			struct page *page = frag->page;
+			struct page *page = skb_frag_page(frag);
 
 			if (copy > len)
 				copy = len;
@@ -418,7 +418,7 @@  int skb_copy_datagram_const_iovec(const struct sk_buff *skb, int offset,
 			int err;
 			u8  *vaddr;
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			struct page *page = frag->page;
+			struct page *page = skb_frag_page(frag);
 
 			if (copy > len)
 				copy = len;
@@ -508,7 +508,7 @@  int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
 			int err;
 			u8  *vaddr;
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			struct page *page = frag->page;
+			struct page *page = skb_frag_page(frag);
 
 			if (copy > len)
 				copy = len;
@@ -594,7 +594,7 @@  static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
 			int err = 0;
 			u8  *vaddr;
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			struct page *page = frag->page;
+			struct page *page = skb_frag_page(frag);
 
 			if (copy > len)
 				copy = len;
diff --git a/net/core/dev.c b/net/core/dev.c
index a4306f7..4053008 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1949,9 +1949,11 @@  static int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 #ifdef CONFIG_HIGHMEM
 	int i;
 	if (!(dev->features & NETIF_F_HIGHDMA)) {
-		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-			if (PageHighMem(skb_shinfo(skb)->frags[i].page))
+		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+			if (PageHighMem(skb_frag_page(frag)))
 				return 1;
+		}
 	}
 
 	if (PCI_DMA_BUS_IS_PHYS) {
@@ -1960,7 +1962,8 @@  static int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 		if (!pdev)
 			return 0;
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-			dma_addr_t addr = page_to_phys(skb_shinfo(skb)->frags[i].page);
+			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+			dma_addr_t addr = page_to_phys(skb_frag_page(frag));
 			if (!pdev->dma_mask || addr + PAGE_SIZE - 1 > *pdev->dma_mask)
 				return 1;
 		}
@@ -3472,7 +3475,7 @@  pull:
 		skb_shinfo(skb)->frags[0].size -= grow;
 
 		if (unlikely(!skb_shinfo(skb)->frags[0].size)) {
-			put_page(skb_shinfo(skb)->frags[0].page);
+			skb_frag_unref(skb, 0);
 			memmove(skb_shinfo(skb)->frags,
 				skb_shinfo(skb)->frags + 1,
 				--skb_shinfo(skb)->nr_frags * sizeof(skb_frag_t));
@@ -3536,10 +3539,9 @@  void skb_gro_reset_offset(struct sk_buff *skb)
 	NAPI_GRO_CB(skb)->frag0_len = 0;
 
 	if (skb->mac_header == skb->tail &&
-	    !PageHighMem(skb_shinfo(skb)->frags[0].page)) {
+	    !PageHighMem(skb_frag_page(&skb_shinfo(skb)->frags[0]))) {
 		NAPI_GRO_CB(skb)->frag0 =
-			page_address(skb_shinfo(skb)->frags[0].page) +
-			skb_shinfo(skb)->frags[0].page_offset;
+			skb_frag_address(&skb_shinfo(skb)->frags[0]);
 		NAPI_GRO_CB(skb)->frag0_len = skb_shinfo(skb)->frags[0].size;
 	}
 }
diff --git a/net/core/kmap_skb.h b/net/core/kmap_skb.h
index 283c2b9..81e1ed7 100644
--- a/net/core/kmap_skb.h
+++ b/net/core/kmap_skb.h
@@ -7,7 +7,7 @@  static inline void *kmap_skb_frag(const skb_frag_t *frag)
 
 	local_bh_disable();
 #endif
-	return kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ);
+	return kmap_atomic(skb_frag_page(frag), KM_SKB_DATA_SOFTIRQ);
 }
 
 static inline void kunmap_skb_frag(void *vaddr)
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index e35a6fb..796044a 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2602,8 +2602,7 @@  static void pktgen_finalize_skb(struct pktgen_dev *pkt_dev, struct sk_buff *skb,
 				if (!pkt_dev->page)
 					break;
 			}
-			skb_shinfo(skb)->frags[i].page = pkt_dev->page;
-			get_page(pkt_dev->page);
+			skb_frag_set_page(skb, i, pkt_dev->page);
 			skb_shinfo(skb)->frags[i].page_offset = 0;
 			/*last fragment, fill rest of data*/
 			if (i == (frags - 1))
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index e27334e..296afd0 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -326,7 +326,7 @@  static void skb_release_data(struct sk_buff *skb)
 		if (skb_shinfo(skb)->nr_frags) {
 			int i;
 			for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-				put_page(skb_shinfo(skb)->frags[i].page);
+				skb_frag_unref(skb, i);
 		}
 
 		/*
@@ -809,7 +809,7 @@  struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
 		}
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 			skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
-			get_page(skb_shinfo(n)->frags[i].page);
+			skb_frag_ref(skb, i);
 		}
 		skb_shinfo(n)->nr_frags = i;
 	}
@@ -901,7 +901,7 @@  int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 			skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
 		}
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
-			get_page(skb_shinfo(skb)->frags[i].page);
+			skb_frag_ref(skb, i);
 
 		if (skb_has_frag_list(skb))
 			skb_clone_fraglist(skb);
@@ -1181,7 +1181,7 @@  drop_pages:
 		skb_shinfo(skb)->nr_frags = i;
 
 		for (; i < nfrags; i++)
-			put_page(skb_shinfo(skb)->frags[i].page);
+			skb_frag_unref(skb, i);
 
 		if (skb_has_frag_list(skb))
 			skb_drop_fraglist(skb);
@@ -1350,7 +1350,7 @@  pull_pages:
 	k = 0;
 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 		if (skb_shinfo(skb)->frags[i].size <= eat) {
-			put_page(skb_shinfo(skb)->frags[i].page);
+			skb_frag_unref(skb, i);
 			eat -= skb_shinfo(skb)->frags[i].size;
 		} else {
 			skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
@@ -1609,7 +1609,8 @@  static int __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 	for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) {
 		const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];
 
-		if (__splice_segment(f->page, f->page_offset, f->size,
+		if (__splice_segment(skb_frag_page(f),
+				     f->page_offset, f->size,
 				     offset, len, skb, spd, 0, sk, pipe))
 			return 1;
 	}
@@ -2154,7 +2155,7 @@  static inline void skb_split_no_header(struct sk_buff *skb,
 				 *    where splitting is expensive.
 				 * 2. Split is accurately. We make this.
 				 */
-				get_page(skb_shinfo(skb)->frags[i].page);
+				skb_frag_ref(skb, i);
 				skb_shinfo(skb1)->frags[0].page_offset += len - pos;
 				skb_shinfo(skb1)->frags[0].size -= len - pos;
 				skb_shinfo(skb)->frags[i].size	= len - pos;
@@ -2229,7 +2230,8 @@  int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 	 * commit all, so that we don't have to undo partial changes
 	 */
 	if (!to ||
-	    !skb_can_coalesce(tgt, to, fragfrom->page, fragfrom->page_offset)) {
+	    !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
+			      fragfrom->page_offset)) {
 		merge = -1;
 	} else {
 		merge = to - 1;
@@ -2276,7 +2278,7 @@  int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 			to++;
 
 		} else {
-			get_page(fragfrom->page);
+			__skb_frag_ref(fragfrom);
 			fragto->page = fragfrom->page;
 			fragto->page_offset = fragfrom->page_offset;
 			fragto->size = todo;
@@ -2298,7 +2300,7 @@  int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 		fragto = &skb_shinfo(tgt)->frags[merge];
 
 		fragto->size += fragfrom->size;
-		put_page(fragfrom->page);
+		__skb_frag_unref(fragfrom);
 	}
 
 	/* Reposition in the original skb */
@@ -2543,8 +2545,7 @@  int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
 		left = PAGE_SIZE - frag->page_offset;
 		copy = (length > left)? left : length;
 
-		ret = getfrag(from, (page_address(frag->page) +
-			    frag->page_offset + frag->size),
+		ret = getfrag(from, skb_frag_address(frag) + frag->size,
 			    offset, copy, 0, skb);
 		if (ret < 0)
 			return -EFAULT;
@@ -2696,7 +2697,7 @@  struct sk_buff *skb_segment(struct sk_buff *skb, u32 features)
 
 		while (pos < offset + len && i < nfrags) {
 			*frag = skb_shinfo(skb)->frags[i];
-			get_page(frag->page);
+			__skb_frag_ref(frag);
 			size = frag->size;
 
 			if (pos < offset) {
@@ -2919,7 +2920,7 @@  __skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len)
 
 			if (copy > len)
 				copy = len;
-			sg_set_page(&sg[elt], frag->page, copy,
+			sg_set_page(&sg[elt], skb_frag_page(frag), copy,
 					frag->page_offset+offset-start);
 			elt++;
 			if (!(len -= copy))
diff --git a/net/core/sock.c b/net/core/sock.c
index 9997026..b29ab61 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1533,7 +1533,6 @@  struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
 				skb_shinfo(skb)->nr_frags = npages;
 				for (i = 0; i < npages; i++) {
 					struct page *page;
-					skb_frag_t *frag;
 
 					page = alloc_pages(sk->sk_allocation, 0);
 					if (!page) {
@@ -1543,12 +1542,11 @@  struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
 						goto failure;
 					}
 
-					frag = &skb_shinfo(skb)->frags[i];
-					frag->page = page;
-					frag->page_offset = 0;
-					frag->size = (data_len >= PAGE_SIZE ?
-						      PAGE_SIZE :
-						      data_len);
+					__skb_fill_page_desc(skb, i,
+							page, 0,
+							(data_len >= PAGE_SIZE ?
+							 PAGE_SIZE :
+							 data_len));
 					data_len -= PAGE_SIZE;
 				}
 
diff --git a/net/core/user_dma.c b/net/core/user_dma.c
index 25d717e..34e9664 100644
--- a/net/core/user_dma.c
+++ b/net/core/user_dma.c
@@ -78,7 +78,7 @@  int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
 		copy = end - offset;
 		if (copy > 0) {
 			skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
-			struct page *page = frag->page;
+			struct page *page = skb_frag_page(frag);
 
 			if (copy > len)
 				copy = len;