diff mbox series

[net-next,v2,2/3] net: mirror skb frag ref/unref helpers

Message ID 20240327214523.2182174-3-almasrymina@google.com (mailing list archive)
State Superseded
Headers show
Series Minor cleanups to skb frag ref/unref | expand

Commit Message

Mina Almasry March 27, 2024, 9:45 p.m. UTC 
Refactor some of the skb frag ref/unref helpers for improved clarity.

Implement napi_pp_get_page() to be the mirror counterpart of
napi_pp_put_page().

Implement skb_page_ref() to be the mirror of skb_page_unref().

Improve __skb_frag_ref() to become a mirror counterpart of
__skb_frag_unref(). Previously unref could handle pp & non-pp pages,
while the ref could only handle non-pp pages. Now both the ref & unref
helpers can correctly handle both pp & non-pp pages.

Now that __skb_frag_ref() can handle both pp & non-pp pages, remove
skb_pp_frag_ref(), and use __skb_frag_ref() instead.  This lets us
remove pp specific handling from skb_try_coalesce.

Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>

---
 .../chelsio/inline_crypto/ch_ktls/chcr_ktls.c |  2 +-
 drivers/net/ethernet/sun/cassini.c            |  4 +-
 include/linux/skbuff.h                        | 22 ++++++--
 net/core/skbuff.c                             | 54 ++++++-------------
 4 files changed, 38 insertions(+), 44 deletions(-)

Comments

kernel test robot March 28, 2024, 5:07 p.m. UTC | #1 
Hi Mina,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Mina-Almasry/net-make-napi_frag_unref-reuse-skb_page_unref/20240328-054816
base:   net-next/main
patch link:    https://lore.kernel.org/r/20240327214523.2182174-3-almasrymina%40google.com
patch subject: [PATCH net-next v2 2/3] net: mirror skb frag ref/unref helpers
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240329/202403290006.WfusvToB-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240329/202403290006.WfusvToB-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403290006.WfusvToB-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/tls/tls_device_fallback.c:280:22: error: too few arguments to function call, expected 2, have 1
     280 |                 __skb_frag_ref(frag);
         |                 ~~~~~~~~~~~~~~     ^
   include/linux/skbuff.h:3517:20: note: '__skb_frag_ref' declared here
    3517 | static inline void __skb_frag_ref(skb_frag_t *frag, bool recycle)
         |                    ^              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 error generated.


vim +280 net/tls/tls_device_fallback.c

e8f69799810c32 Ilya Lesokhin  2018-04-30  228  
e8f69799810c32 Ilya Lesokhin  2018-04-30  229  /* This function may be called after the user socket is already
e8f69799810c32 Ilya Lesokhin  2018-04-30  230   * closed so make sure we don't use anything freed during
e8f69799810c32 Ilya Lesokhin  2018-04-30  231   * tls_sk_proto_close here
e8f69799810c32 Ilya Lesokhin  2018-04-30  232   */
e8f69799810c32 Ilya Lesokhin  2018-04-30  233  
e8f69799810c32 Ilya Lesokhin  2018-04-30  234  static int fill_sg_in(struct scatterlist *sg_in,
e8f69799810c32 Ilya Lesokhin  2018-04-30  235  		      struct sk_buff *skb,
d80a1b9d186057 Boris Pismenny 2018-07-13  236  		      struct tls_offload_context_tx *ctx,
e8f69799810c32 Ilya Lesokhin  2018-04-30  237  		      u64 *rcd_sn,
e8f69799810c32 Ilya Lesokhin  2018-04-30  238  		      s32 *sync_size,
e8f69799810c32 Ilya Lesokhin  2018-04-30  239  		      int *resync_sgs)
e8f69799810c32 Ilya Lesokhin  2018-04-30  240  {
504148fedb8542 Eric Dumazet   2022-06-30  241  	int tcp_payload_offset = skb_tcp_all_headers(skb);
e8f69799810c32 Ilya Lesokhin  2018-04-30  242  	int payload_len = skb->len - tcp_payload_offset;
e8f69799810c32 Ilya Lesokhin  2018-04-30  243  	u32 tcp_seq = ntohl(tcp_hdr(skb)->seq);
e8f69799810c32 Ilya Lesokhin  2018-04-30  244  	struct tls_record_info *record;
e8f69799810c32 Ilya Lesokhin  2018-04-30  245  	unsigned long flags;
e8f69799810c32 Ilya Lesokhin  2018-04-30  246  	int remaining;
e8f69799810c32 Ilya Lesokhin  2018-04-30  247  	int i;
e8f69799810c32 Ilya Lesokhin  2018-04-30  248  
e8f69799810c32 Ilya Lesokhin  2018-04-30  249  	spin_lock_irqsave(&ctx->lock, flags);
e8f69799810c32 Ilya Lesokhin  2018-04-30  250  	record = tls_get_record(ctx, tcp_seq, rcd_sn);
e8f69799810c32 Ilya Lesokhin  2018-04-30  251  	if (!record) {
e8f69799810c32 Ilya Lesokhin  2018-04-30  252  		spin_unlock_irqrestore(&ctx->lock, flags);
e8f69799810c32 Ilya Lesokhin  2018-04-30  253  		return -EINVAL;
e8f69799810c32 Ilya Lesokhin  2018-04-30  254  	}
e8f69799810c32 Ilya Lesokhin  2018-04-30  255  
e8f69799810c32 Ilya Lesokhin  2018-04-30  256  	*sync_size = tcp_seq - tls_record_start_seq(record);
e8f69799810c32 Ilya Lesokhin  2018-04-30  257  	if (*sync_size < 0) {
e8f69799810c32 Ilya Lesokhin  2018-04-30  258  		int is_start_marker = tls_record_is_start_marker(record);
e8f69799810c32 Ilya Lesokhin  2018-04-30  259  
e8f69799810c32 Ilya Lesokhin  2018-04-30  260  		spin_unlock_irqrestore(&ctx->lock, flags);
e8f69799810c32 Ilya Lesokhin  2018-04-30  261  		/* This should only occur if the relevant record was
e8f69799810c32 Ilya Lesokhin  2018-04-30  262  		 * already acked. In that case it should be ok
e8f69799810c32 Ilya Lesokhin  2018-04-30  263  		 * to drop the packet and avoid retransmission.
e8f69799810c32 Ilya Lesokhin  2018-04-30  264  		 *
e8f69799810c32 Ilya Lesokhin  2018-04-30  265  		 * There is a corner case where the packet contains
e8f69799810c32 Ilya Lesokhin  2018-04-30  266  		 * both an acked and a non-acked record.
e8f69799810c32 Ilya Lesokhin  2018-04-30  267  		 * We currently don't handle that case and rely
a0e128ef88e4a0 Yueh-Shun Li   2023-06-22  268  		 * on TCP to retransmit a packet that doesn't contain
e8f69799810c32 Ilya Lesokhin  2018-04-30  269  		 * already acked payload.
e8f69799810c32 Ilya Lesokhin  2018-04-30  270  		 */
e8f69799810c32 Ilya Lesokhin  2018-04-30  271  		if (!is_start_marker)
e8f69799810c32 Ilya Lesokhin  2018-04-30  272  			*sync_size = 0;
e8f69799810c32 Ilya Lesokhin  2018-04-30  273  		return -EINVAL;
e8f69799810c32 Ilya Lesokhin  2018-04-30  274  	}
e8f69799810c32 Ilya Lesokhin  2018-04-30  275  
e8f69799810c32 Ilya Lesokhin  2018-04-30  276  	remaining = *sync_size;
e8f69799810c32 Ilya Lesokhin  2018-04-30  277  	for (i = 0; remaining > 0; i++) {
e8f69799810c32 Ilya Lesokhin  2018-04-30  278  		skb_frag_t *frag = &record->frags[i];
e8f69799810c32 Ilya Lesokhin  2018-04-30  279  
e8f69799810c32 Ilya Lesokhin  2018-04-30 @280  		__skb_frag_ref(frag);
e8f69799810c32 Ilya Lesokhin  2018-04-30  281  		sg_set_page(sg_in + i, skb_frag_page(frag),
b54c9d5bd6e38e Jonathan Lemon 2019-07-30  282  			    skb_frag_size(frag), skb_frag_off(frag));
e8f69799810c32 Ilya Lesokhin  2018-04-30  283  
e8f69799810c32 Ilya Lesokhin  2018-04-30  284  		remaining -= skb_frag_size(frag);
e8f69799810c32 Ilya Lesokhin  2018-04-30  285  
e8f69799810c32 Ilya Lesokhin  2018-04-30  286  		if (remaining < 0)
e8f69799810c32 Ilya Lesokhin  2018-04-30  287  			sg_in[i].length += remaining;
e8f69799810c32 Ilya Lesokhin  2018-04-30  288  	}
e8f69799810c32 Ilya Lesokhin  2018-04-30  289  	*resync_sgs = i;
e8f69799810c32 Ilya Lesokhin  2018-04-30  290  
e8f69799810c32 Ilya Lesokhin  2018-04-30  291  	spin_unlock_irqrestore(&ctx->lock, flags);
e8f69799810c32 Ilya Lesokhin  2018-04-30  292  	if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0)
e8f69799810c32 Ilya Lesokhin  2018-04-30  293  		return -EINVAL;
e8f69799810c32 Ilya Lesokhin  2018-04-30  294  
e8f69799810c32 Ilya Lesokhin  2018-04-30  295  	return 0;
e8f69799810c32 Ilya Lesokhin  2018-04-30  296  }
e8f69799810c32 Ilya Lesokhin  2018-04-30  297
kernel test robot March 28, 2024, 5:18 p.m. UTC | #2 
Hi Mina,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Mina-Almasry/net-make-napi_frag_unref-reuse-skb_page_unref/20240328-054816
base:   net-next/main
patch link:    https://lore.kernel.org/r/20240327214523.2182174-3-almasrymina%40google.com
patch subject: [PATCH net-next v2 2/3] net: mirror skb frag ref/unref helpers
config: riscv-defconfig (https://download.01.org/0day-ci/archive/20240329/202403290103.BHENUIYW-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 23de3862dce582ce91c1aa914467d982cb1a73b4)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240329/202403290103.BHENUIYW-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403290103.BHENUIYW-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from net/core/skbuff.c:40:
   In file included from include/linux/mm.h:2208:
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> net/core/skbuff.c:1016:21: error: use of undeclared identifier 'head_page'
    1016 |         page_pool_ref_page(head_page);
         |                            ^
   1 warning and 1 error generated.


vim +/head_page +1016 net/core/skbuff.c

  1010	
  1011		page = compound_head(page);
  1012	
  1013		if (!is_pp_page(page))
  1014			return false;
  1015	
> 1016		page_pool_ref_page(head_page);
  1017		return true;
  1018	}
  1019	EXPORT_SYMBOL(napi_pp_get_page);
  1020
diff mbox series

Patch

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
index 6482728794dd..f9b0a9533985 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
@@ -1658,7 +1658,7 @@  static void chcr_ktls_copy_record_in_skb(struct sk_buff *nskb,
 	for (i = 0; i < record->num_frags; i++) {
 		skb_shinfo(nskb)->frags[i] = record->frags[i];
 		/* increase the frag ref count */
-		__skb_frag_ref(&skb_shinfo(nskb)->frags[i]);
+		__skb_frag_ref(&skb_shinfo(nskb)->frags[i], false);
 	}
 
 	skb_shinfo(nskb)->nr_frags = record->num_frags;
diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index bfb903506367..fabba729e1b8 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -1999,7 +1999,7 @@  static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
 		skb->len      += hlen - swivel;
 
 		skb_frag_fill_page_desc(frag, page->buffer, off, hlen - swivel);
-		__skb_frag_ref(frag);
+		__skb_frag_ref(frag, false);
 
 		/* any more data? */
 		if ((words[0] & RX_COMP1_SPLIT_PKT) && ((dlen -= hlen) > 0)) {
@@ -2023,7 +2023,7 @@  static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
 			frag++;
 
 			skb_frag_fill_page_desc(frag, page->buffer, 0, hlen);
-			__skb_frag_ref(frag);
+			__skb_frag_ref(frag, false);
 			RX_USED_ADD(page, hlen + cp->crc_size);
 		}
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bafa5c9ff59a..058d72a2a250 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3494,15 +3494,29 @@  static inline struct page *skb_frag_page(const skb_frag_t *frag)
 	return netmem_to_page(frag->netmem);
 }
 
+bool napi_pp_get_page(struct page *page);
+
+static inline void skb_page_ref(struct page *page, bool recycle)
+{
+#ifdef CONFIG_PAGE_POOL
+	if (recycle && napi_pp_get_page(page))
+		return;
+#endif
+	get_page(page);
+}
+
 /**
  * __skb_frag_ref - take an addition reference on a paged fragment.
  * @frag: the paged fragment
+ * @recycle: skb->pp_recycle param of the parent skb. False if no parent skb.
  *
- * Takes an additional reference on the paged fragment @frag.
+ * Takes an additional reference on the paged fragment @frag. Obtains the
+ * correct reference count depending on whether skb->pp_recycle is set and
+ * whether the frag is a page pool frag.
  */
-static inline void __skb_frag_ref(skb_frag_t *frag)
+static inline void __skb_frag_ref(skb_frag_t *frag, bool recycle)
 {
-	get_page(skb_frag_page(frag));
+	skb_page_ref(skb_frag_page(frag), recycle);
 }
 
 /**
@@ -3514,7 +3528,7 @@  static inline void __skb_frag_ref(skb_frag_t *frag)
  */
 static inline void skb_frag_ref(struct sk_buff *skb, int f)
 {
-	__skb_frag_ref(&skb_shinfo(skb)->frags[f]);
+	__skb_frag_ref(&skb_shinfo(skb)->frags[f], skb->pp_recycle);
 }
 
 int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 17617c29be2d..5c86ecaceb6c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1005,6 +1005,19 @@  int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
 EXPORT_SYMBOL(skb_cow_data_for_xdp);
 
 #if IS_ENABLED(CONFIG_PAGE_POOL)
+bool napi_pp_get_page(struct page *page)
+{
+
+	page = compound_head(page);
+
+	if (!is_pp_page(page))
+		return false;
+
+	page_pool_ref_page(head_page);
+	return true;
+}
+EXPORT_SYMBOL(napi_pp_get_page);
+
 bool napi_pp_put_page(struct page *page, bool napi_safe)
 {
 	bool allow_direct = false;
@@ -1057,37 +1070,6 @@  static bool skb_pp_recycle(struct sk_buff *skb, void *data, bool napi_safe)
 	return napi_pp_put_page(virt_to_page(data), napi_safe);
 }
 
-/**
- * skb_pp_frag_ref() - Increase fragment references of a page pool aware skb
- * @skb:	page pool aware skb
- *
- * Increase the fragment reference count (pp_ref_count) of a skb. This is
- * intended to gain fragment references only for page pool aware skbs,
- * i.e. when skb->pp_recycle is true, and not for fragments in a
- * non-pp-recycling skb. It has a fallback to increase references on normal
- * pages, as page pool aware skbs may also have normal page fragments.
- */
-static int skb_pp_frag_ref(struct sk_buff *skb)
-{
-	struct skb_shared_info *shinfo;
-	struct page *head_page;
-	int i;
-
-	if (!skb->pp_recycle)
-		return -EINVAL;
-
-	shinfo = skb_shinfo(skb);
-
-	for (i = 0; i < shinfo->nr_frags; i++) {
-		head_page = compound_head(skb_frag_page(&shinfo->frags[i]));
-		if (likely(is_pp_page(head_page)))
-			page_pool_ref_page(head_page);
-		else
-			page_ref_inc(head_page);
-	}
-	return 0;
-}
-
 static void skb_kfree_head(void *head, unsigned int end_offset)
 {
 	if (end_offset == SKB_SMALL_HEAD_HEADROOM)
@@ -4196,7 +4178,7 @@  int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 			to++;
 
 		} else {
-			__skb_frag_ref(fragfrom);
+			__skb_frag_ref(fragfrom, skb->pp_recycle);
 			skb_frag_page_copy(fragto, fragfrom);
 			skb_frag_off_copy(fragto, fragfrom);
 			skb_frag_size_set(fragto, todo);
@@ -4846,7 +4828,7 @@  struct sk_buff *skb_segment(struct sk_buff *head_skb,
 			}
 
 			*nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
-			__skb_frag_ref(nskb_frag);
+			__skb_frag_ref(nskb_frag, nskb->pp_recycle);
 			size = skb_frag_size(nskb_frag);
 
 			if (pos < offset) {
@@ -5977,10 +5959,8 @@  bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 	/* if the skb is not cloned this does nothing
 	 * since we set nr_frags to 0.
 	 */
-	if (skb_pp_frag_ref(from)) {
-		for (i = 0; i < from_shinfo->nr_frags; i++)
-			__skb_frag_ref(&from_shinfo->frags[i]);
-	}
+	for (i = 0; i < from_shinfo->nr_frags; i++)
+		__skb_frag_ref(&from_shinfo->frags[i], from->pp_recycle);
 
 	to->truesize += delta;
 	to->len += len;