Merge branch 'Convert-skb_frag_t-to-bio_vec'

Matthew Wilcox says:

====================
Convert skb_frag_t to bio_vec

The skb_frag_t and bio_vec are fundamentally the same (page, offset,
length) tuple.  This patch series unifies the two, leaving the
skb_frag_t typedef in place.  This has the immediate advantage that
we already have iov_iter support for bvecs and don't need to add
support for iterating skbuffs.  It enables a long-term plan to use
bvecs more broadly within the kernel and should make network-storage
drivers able to do less work converting between skbuffs and biovecs.

It will consume more memory on 32-bit kernels.  If that proves
problematic, we can look at ways of addressing it.

v3: Rebase on latest Linus with net-next merged.
  - Reorder the uncontroversial 'Use skb accessors' patches first so you
    can apply just those two if you want to hold off on the full
    conversion.
  - Convert all the users of 'struct skb_frag_struct' to skb_frag_t.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 24 deletions

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index a032f01e928c..7f2b2ea9399c 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -18,7 +18,10 @@
 struct bio_vec {
 	struct page	*bv_page;
 	unsigned int	bv_len;
-	unsigned int	bv_offset;
+	union {
+		__u32		page_offset;
+		unsigned int	bv_offset;
+	};
 };
 
 struct bvec_iter {
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d8af86d995d6..718742b1c505 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -14,6 +14,7 @@
 #include <linux/compiler.h>
 #include <linux/time.h>
 #include <linux/bug.h>
+#include <linux/bvec.h>
 #include <linux/cache.h>
 #include <linux/rbtree.h>
 #include <linux/socket.h>
@@ -308,20 +309,7 @@ extern int sysctl_max_skb_frags;
  */
 #define GSO_BY_FRAGS	0xFFFF
 
-typedef struct skb_frag_struct skb_frag_t;
-
-struct skb_frag_struct {
-	struct {
-		struct page *p;
-	} page;
-#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
-	__u32 page_offset;
-	__u32 size;
-#else
-	__u16 page_offset;
-	__u16 size;
-#endif
-};
+typedef struct bio_vec skb_frag_t;
 
 /**
  * skb_frag_size - Returns the size of a skb fragment
@@ -329,7 +317,7 @@ struct skb_frag_struct {
  */
 static inline unsigned int skb_frag_size(const skb_frag_t *frag)
 {
-	return frag->size;
+	return frag->bv_len;
 }
 
 /**
@@ -339,7 +327,7 @@ static inline unsigned int skb_frag_size(const skb_frag_t *frag)
  */
 static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
 {
-	frag->size = size;
+	frag->bv_len = size;
 }
 
 /**
@@ -349,7 +337,7 @@ static inline void skb_frag_size_set(skb_frag_t *frag, unsigned int size)
  */
 static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
 {
-	frag->size += delta;
+	frag->bv_len += delta;
 }
 
 /**
@@ -359,7 +347,7 @@ static inline void skb_frag_size_add(skb_frag_t *frag, int delta)
  */
 static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
 {
-	frag->size -= delta;
+	frag->bv_len -= delta;
 }
 
 /**
@@ -379,7 +367,7 @@ static inline bool skb_frag_must_loop(struct page *p)
  *	skb_frag_foreach_page - loop over pages in a fragment
  *
  *	@f:		skb frag to operate on
- *	@f_off:		offset from start of f->page.p
+ *	@f_off:		offset from start of f->bv_page
  *	@f_len:		length from f_off to loop over
  *	@p:		(temp var) current page
  *	@p_off:		(temp var) offset from start of current page,
@@ -2089,7 +2077,7 @@ static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
 	 * that not all callers have unique ownership of the page but rely
 	 * on page_is_pfmemalloc doing the right thing(tm).
 	 */
-	frag->page.p		  = page;
+	frag->bv_page		  = page;
 	frag->page_offset	  = off;
 	skb_frag_size_set(frag, size);
 
@@ -2877,7 +2865,7 @@ static inline void skb_propagate_pfmemalloc(struct page *page,
  */
 static inline struct page *skb_frag_page(const skb_frag_t *frag)
 {
-	return frag->page.p;
+	return frag->bv_page;
 }
 
 /**
@@ -2963,7 +2951,7 @@ static inline void *skb_frag_address_safe(const skb_frag_t *frag)
  */
 static inline void __skb_frag_set_page(skb_frag_t *frag, struct page *page)
 {
-	frag->page.p = page;
+	frag->bv_page = page;
 }
 
 /**
@@ -3166,7 +3154,7 @@ static inline bool skb_can_coalesce(struct sk_buff *skb, int i,
 	if (skb_zcopy(skb))
 		return false;
 	if (i) {
-		const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[i - 1];
+		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i - 1];
 
 		return page == skb_frag_page(frag) &&
 		       off == frag->page_offset + skb_frag_size(frag);