[PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Michal Luczaj]

Couple of cleanup patches to get rid of unused function parameters around
skbuff.c, plus little things spotted along the way.

Offshoot of my question in [1], but way more contained. Found by adding
"-Wunused-parameter -Wno-error" to KBUILD_CFLAGS and grepping for specific
skbuff.c warnings.

[1]: https://lore.kernel.org/netdev/972af569-0c90-4585-9e1f-f2266dab6ec6@rbox.co/

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
Changes in v2:
- Fix typos in commit messages
- Remove one more unused parameter in skbuff.c (patch 9)
- Collect R-b, add a one-line cleanup of smc_rx_splice() (patch 7) [Simon]
- Link to v1: https://lore.kernel.org/r/20250624-splice-drop-unused-v1-0-cf641a676d04@rbox.co

---
Michal Luczaj (9):
      net: splice: Drop unused @pipe
      net: splice: Drop unused @flags
      tcp: Drop tcp_splice_state::flags
      af_unix: Drop unix_stream_read_state::splice_flags
      net: splice: Drop unused @gfp
      net: splice: Drop nr_pages_max initialization
      net/smc: Drop nr_pages_max initialization
      net: skbuff: Drop unused @skb
      net: skbuff: Drop unused @skb

 .../chelsio/inline_crypto/chtls/chtls_io.c         |  3 +-
 include/linux/skbuff.h                             |  5 ++-
 net/core/skbuff.c                                  | 37 ++++++++--------------
 net/ipv4/ip_output.c                               |  3 +-
 net/ipv4/tcp.c                                     |  7 ++--
 net/ipv6/ip6_output.c                              |  3 +-
 net/kcm/kcmsock.c                                  |  5 ++-
 net/smc/smc_rx.c                                   |  1 -
 net/tls/tls_sw.c                                   |  2 +-
 net/unix/af_unix.c                                 |  7 ++--
 10 files changed, 26 insertions(+), 47 deletions(-)
---
base-commit: a9b24b3583ae1da7dbda031f141264f2da260219
change-id: 20250618-splice-drop-unused-0e4ea8a12681

Best regards,
-- 
Michal Luczaj <mhal@rbox.co>

[PATCH net-next v2 1/9] net: splice: Drop unused @pipe

[Michal Luczaj]

Since commit 41c73a0d44c9 ("net: speedup skb_splice_bits()"),
__splice_segment() and spd_fill_page() do not use the @pipe argument. Drop
it.

While adapting the callers, move one line to enforce reverse xmas tree
order.

No functional change intended.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/core/skbuff.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d6420b74ea9c6a9c53a7c16634cce82a1cd1bbd3..ae0f1aae3c91d914020c64e0703732b9c6cd8511 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3060,10 +3060,8 @@ static bool spd_can_coalesce(const struct splice_pipe_desc *spd,
 /*
  * Fill page/offset/length into spd, if it can hold more pages.
  */
-static bool spd_fill_page(struct splice_pipe_desc *spd,
-			  struct pipe_inode_info *pipe, struct page *page,
-			  unsigned int *len, unsigned int offset,
-			  bool linear,
+static bool spd_fill_page(struct splice_pipe_desc *spd, struct page *page,
+			  unsigned int *len, unsigned int offset, bool linear,
 			  struct sock *sk)
 {
 	if (unlikely(spd->nr_pages == MAX_SKB_FRAGS))
@@ -3091,8 +3089,7 @@ static bool __splice_segment(struct page *page, unsigned int poff,
 			     unsigned int plen, unsigned int *off,
 			     unsigned int *len,
 			     struct splice_pipe_desc *spd, bool linear,
-			     struct sock *sk,
-			     struct pipe_inode_info *pipe)
+			     struct sock *sk)
 {
 	if (!*len)
 		return true;
@@ -3111,8 +3108,7 @@ static bool __splice_segment(struct page *page, unsigned int poff,
 	do {
 		unsigned int flen = min(*len, plen);
 
-		if (spd_fill_page(spd, pipe, page, &flen, poff,
-				  linear, sk))
+		if (spd_fill_page(spd, page, &flen, poff, linear, sk))
 			return true;
 		poff += flen;
 		plen -= flen;
@@ -3130,8 +3126,8 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 			      unsigned int *offset, unsigned int *len,
 			      struct splice_pipe_desc *spd, struct sock *sk)
 {
-	int seg;
 	struct sk_buff *iter;
+	int seg;
 
 	/* map the linear part :
 	 * If skb->head_frag is set, this 'linear' part is backed by a
@@ -3143,7 +3139,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 			     skb_headlen(skb),
 			     offset, len, spd,
 			     skb_head_is_locked(skb),
-			     sk, pipe))
+			     sk))
 		return true;
 
 	/*
@@ -3160,7 +3156,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 
 		if (__splice_segment(skb_frag_page(f),
 				     skb_frag_off(f), skb_frag_size(f),
-				     offset, len, spd, false, sk, pipe))
+				     offset, len, spd, false, sk))
 			return true;
 	}
 

-- 
2.49.0

[PATCH net-next v2 2/9] net: splice: Drop unused @flags

[Michal Luczaj]

Since commit 79fddc4efd5d ("new helper: add_to_pipe()") which removed
`spd->flags` check in splice_to_pipe(), skb_splice_bits() does not use the
@flags argument.

Remove it and adapt callers. No functional change intended.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 include/linux/skbuff.h | 3 +--
 net/core/skbuff.c      | 3 +--
 net/ipv4/tcp.c         | 2 +-
 net/kcm/kcmsock.c      | 2 +-
 net/tls/tls_sw.c       | 2 +-
 net/unix/af_unix.c     | 2 +-
 6 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4f6dcb37bae8ada524a1e8f8de44c259cfac695b..5b6f460c69b277124e788cfa0599486522e62c9c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4157,8 +4157,7 @@ int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
 			      int len);
 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
-		    struct pipe_inode_info *pipe, unsigned int len,
-		    unsigned int flags);
+		    struct pipe_inode_info *pipe, unsigned int len);
 int skb_send_sock_locked(struct sock *sk, struct sk_buff *skb, int offset,
 			 int len);
 int skb_send_sock_locked_with_flags(struct sock *sk, struct sk_buff *skb,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ae0f1aae3c91d914020c64e0703732b9c6cd8511..02ead44a82bb71d30d294a6931943d07cf7c7177 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3181,8 +3181,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
  * the fragments, and the frag list.
  */
 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
-		    struct pipe_inode_info *pipe, unsigned int tlen,
-		    unsigned int flags)
+		    struct pipe_inode_info *pipe, unsigned int tlen)
 {
 	struct partial_page partial[MAX_SKB_FRAGS];
 	struct page *pages[MAX_SKB_FRAGS];
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8a3c99246d2ed32ba45849b56830bf128e265763..46997793d87ab40dcd1e1dd041e4641e287e1b7e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -766,7 +766,7 @@ static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 	int ret;
 
 	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
-			      min(rd_desc->count, len), tss->flags);
+			      min(rd_desc->count, len));
 	if (ret > 0)
 		rd_desc->count -= ret;
 	return ret;
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 24aec295a51cf737912f1aefe81556bd9f23331e..8140c9c9cc2cb7aa71eaceab8a019d882bc454aa 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1043,7 +1043,7 @@ static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
 	if (len > stm->full_len)
 		len = stm->full_len;
 
-	copied = skb_splice_bits(skb, sk, stm->offset, pipe, len, flags);
+	copied = skb_splice_bits(skb, sk, stm->offset, pipe, len);
 	if (copied < 0) {
 		err = copied;
 		goto err_out;
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index fc88e34b7f33fefed8aa3c26e1f6eed07cd20853..5bca6cfce749aa9fd64da764b2a0d6a4c936efac 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2266,7 +2266,7 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
 	}
 
 	chunk = min_t(unsigned int, rxm->full_len, len);
-	copied = skb_splice_bits(skb, sk, rxm->offset, pipe, chunk, flags);
+	copied = skb_splice_bits(skb, sk, rxm->offset, pipe, chunk);
 	if (copied < 0)
 		goto splice_requeue;
 
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 1e320f89168d1cd4b5e8fa56565cce9f008ab857..235319a045a1238cf27791dfefa9e61b4a593551 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -3070,7 +3070,7 @@ static int unix_stream_splice_actor(struct sk_buff *skb,
 {
 	return skb_splice_bits(skb, state->socket->sk,
 			       UNIXCB(skb).consumed + skip,
-			       state->pipe, chunk, state->splice_flags);
+			       state->pipe, chunk);
 }
 
 static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,

-- 
2.49.0

[PATCH net-next v2 3/9] tcp: Drop tcp_splice_state::flags

[Michal Luczaj]

Since skb_splice_bits() does not accept @flags anymore, struct's field
became unused. Remove it.

No functional change indented.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/ipv4/tcp.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 46997793d87ab40dcd1e1dd041e4641e287e1b7e..b6285fb1369d32541b9f7d660ca33389b7e4da61 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -324,7 +324,6 @@ EXPORT_IPV6_MOD(tcp_sockets_allocated);
 struct tcp_splice_state {
 	struct pipe_inode_info *pipe;
 	size_t len;
-	unsigned int flags;
 };
 
 /*
@@ -803,7 +802,6 @@ ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 	struct tcp_splice_state tss = {
 		.pipe = pipe,
 		.len = len,
-		.flags = flags,
 	};
 	long timeo;
 	ssize_t spliced;

-- 
2.49.0

[PATCH net-next v2 4/9] af_unix: Drop unix_stream_read_state::splice_flags

[Michal Luczaj]

Since skb_splice_bits() does not accept the @flags argument anymore,
struct's field became unused. Remove it.

No functional change indented.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/unix/af_unix.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 235319a045a1238cf27791dfefa9e61b4a593551..1e3a4db1a96a57c84c199e30c164f66409b04be4 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2674,7 +2674,6 @@ struct unix_stream_read_state {
 	struct pipe_inode_info *pipe;
 	size_t size;
 	int flags;
-	unsigned int splice_flags;
 };
 
 #if IS_ENABLED(CONFIG_AF_UNIX_OOB)
@@ -3082,7 +3081,6 @@ static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,
 		.socket = sock,
 		.pipe = pipe,
 		.size = size,
-		.splice_flags = flags,
 	};
 
 	if (unlikely(*ppos))

-- 
2.49.0

[PATCH net-next v2 5/9] net: splice: Drop unused @gfp

[Michal Luczaj]

Since its introduction in commit 2e910b95329c ("net: Add a function to
splice pages into an skbuff for MSG_SPLICE_PAGES"), skb_splice_from_iter()
never used the @gfp argument. Remove it and adapt callers.

No functional change intended.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c | 3 +--
 include/linux/skbuff.h                                      | 2 +-
 net/core/skbuff.c                                           | 3 +--
 net/ipv4/ip_output.c                                        | 3 +--
 net/ipv4/tcp.c                                              | 3 +--
 net/ipv6/ip6_output.c                                       | 3 +--
 net/kcm/kcmsock.c                                           | 3 +--
 net/unix/af_unix.c                                          | 3 +--
 8 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
index d567e42e176011d42b9549d0cc6292a06126d61d..465fa807796439b90c949f54e203a798f06acf1f 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
@@ -1096,8 +1096,7 @@ int chtls_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 			copy = size;
 
 		if (msg->msg_flags & MSG_SPLICE_PAGES) {
-			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, copy);
 			if (err < 0) {
 				if (err == -EMSGSIZE)
 					goto new_buf;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5b6f460c69b277124e788cfa0599486522e62c9c..4952a6991c720a5001477a77d252567aa2c15ac2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -5264,7 +5264,7 @@ static inline void skb_mark_for_recycle(struct sk_buff *skb)
 }
 
 ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
-			     ssize_t maxsize, gfp_t gfp);
+			     ssize_t maxsize);
 
 #endif	/* __KERNEL__ */
 #endif	/* _LINUX_SKBUFF_H */
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 02ead44a82bb71d30d294a6931943d07cf7c7177..c381a097aa6e087d1b5934f2d193a896a255bf83 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -7229,7 +7229,6 @@ static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
  * @skb: The buffer to add pages to
  * @iter: Iterator representing the pages to be added
  * @maxsize: Maximum amount of pages to be added
- * @gfp: Allocation flags
  *
  * This is a common helper function for supporting MSG_SPLICE_PAGES.  It
  * extracts pages from an iterator and adds them to the socket buffer if
@@ -7240,7 +7239,7 @@ static void skb_splice_csum_page(struct sk_buff *skb, struct page *page,
  * insufficient space in the buffer to transfer anything.
  */
 ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
-			     ssize_t maxsize, gfp_t gfp)
+			     ssize_t maxsize)
 {
 	size_t frag_limit = READ_ONCE(net_hotdata.sysctl_max_skb_frags);
 	struct page *pages[8], **ppages = pages;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index a2705d454fd645b442b2901833afa51b26512512..5d75d60efcf361ed9c3b34eaa982f6c667c716f6 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1222,8 +1222,7 @@ static int __ip_append_data(struct sock *sk,
 			if (WARN_ON_ONCE(copy > msg->msg_iter.count))
 				goto error;
 
-			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, copy);
 			if (err < 0)
 				goto error;
 			copy = err;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b6285fb1369d32541b9f7d660ca33389b7e4da61..9d41113e3a68455f3cc7e067d72f3aa2485a21f2 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1295,8 +1295,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 			if (!copy)
 				goto wait_for_space;
 
-			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, copy);
 			if (err < 0) {
 				if (err == -EMSGSIZE) {
 					tcp_mark_push(tp, skb);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 7bd29a9ff0db8d74c79f50afa5c693231e0f82d5..618ed7d72b28f43ab6d7a02e5f8f53a4d22de87a 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1760,8 +1760,7 @@ static int __ip6_append_data(struct sock *sk,
 			if (WARN_ON_ONCE(copy > msg->msg_iter.count))
 				goto error;
 
-			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, copy);
 			if (err < 0)
 				goto error;
 			copy = err;
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 8140c9c9cc2cb7aa71eaceab8a019d882bc454aa..71fedf9cfac85b7cbcd8fd3dbacd74440fa556f4 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -835,8 +835,7 @@ static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 			if (!sk_wmem_schedule(sk, copy))
 				goto wait_for_memory;
 
-			err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, copy);
 			if (err < 0) {
 				if (err == -EMSGSIZE)
 					goto wait_for_memory;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 1e3a4db1a96a57c84c199e30c164f66409b04be4..c2d1a547b14650b53d16c18f239aeb7c5f50cc96 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2377,8 +2377,7 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 
 		if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
-			err = skb_splice_from_iter(skb, &msg->msg_iter, size,
-						   sk->sk_allocation);
+			err = skb_splice_from_iter(skb, &msg->msg_iter, size);
 			if (err < 0)
 				goto out_free;
 

-- 
2.49.0

[PATCH net-next v2 6/9] net: splice: Drop nr_pages_max initialization

[Michal Luczaj]

splice_pipe_desc::nr_pages_max was initialized unnecessarily in commit
41c73a0d44c9 ("net: speedup skb_splice_bits()"). spd_fill_page() compares
spd->nr_pages against a constant MAX_SKB_FRAGS, which makes setting
nr_pages_max redundant.

Remove the assignment. No functional change intended.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/core/skbuff.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index c381a097aa6e087d1b5934f2d193a896a255bf83..b4f7843430a3f8f84aed387bf41ae761d97687ad 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3188,7 +3188,6 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
 	struct splice_pipe_desc spd = {
 		.pages = pages,
 		.partial = partial,
-		.nr_pages_max = MAX_SKB_FRAGS,
 		.ops = &nosteal_pipe_buf_ops,
 		.spd_release = sock_spd_release,
 	};

-- 
2.49.0

[PATCH net-next v2 7/9] net/smc: Drop nr_pages_max initialization

[Michal Luczaj]

splice_pipe_desc::nr_pages_max was initialized unnecessarily in
commit b8d199451c99 ("net/smc: Allow virtually contiguous sndbufs or RMBs
for SMC-R"). Struct's field is unused in this context.

Remove the assignment. No functional change intended.

Suggested-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/smc/smc_rx.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index e7f1134453ef40dd81a9574d6df4ead95acd8ae5..bbba5d4dc7eb0dbb31a9800023b0caab33e87842 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -202,7 +202,6 @@ static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len,
 			offset = 0;
 		}
 	}
-	spd.nr_pages_max = nr_pages;
 	spd.nr_pages = nr_pages;
 	spd.pages = pages;
 	spd.partial = partial;

-- 
2.49.0

Re: [PATCH net-next v2 7/9] net/smc: Drop nr_pages_max initialization

[Sidraya Jayagond]

On 26/06/25 2:03 pm, Michal Luczaj wrote:
> splice_pipe_desc::nr_pages_max was initialized unnecessarily in
> commit b8d199451c99 ("net/smc: Allow virtually contiguous sndbufs or RMBs
> for SMC-R"). Struct's field is unused in this context.
> 
> Remove the assignment. No functional change intended.
> 
> Suggested-by: Simon Horman <horms@kernel.org>
> Signed-off-by: Michal Luczaj <mhal@rbox.co>
> ---
>   net/smc/smc_rx.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
> index e7f1134453ef40dd81a9574d6df4ead95acd8ae5..bbba5d4dc7eb0dbb31a9800023b0caab33e87842 100644
> --- a/net/smc/smc_rx.c
> +++ b/net/smc/smc_rx.c
> @@ -202,7 +202,6 @@ static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len,
>   			offset = 0;
>   		}
>   	}
> -	spd.nr_pages_max = nr_pages;
>   	spd.nr_pages = nr_pages;
>   	spd.pages = pages;
>   	spd.partial = partial;
> 
LGTM.
Reviewed-by: Sidraya Jayagond <sidraya@linux.ibm.com>

Re: [PATCH net-next v2 7/9] net/smc: Drop nr_pages_max initialization

[Simon Horman]

On Thu, Jun 26, 2025 at 10:33:40AM +0200, Michal Luczaj wrote:
> splice_pipe_desc::nr_pages_max was initialized unnecessarily in
> commit b8d199451c99 ("net/smc: Allow virtually contiguous sndbufs or RMBs
> for SMC-R"). Struct's field is unused in this context.
> 
> Remove the assignment. No functional change intended.
> 
> Suggested-by: Simon Horman <horms@kernel.org>
> Signed-off-by: Michal Luczaj <mhal@rbox.co>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next v2 7/9] net/smc: Drop nr_pages_max initialization

[Dust Li]

On 2025-06-26 10:33:40, Michal Luczaj wrote:
>splice_pipe_desc::nr_pages_max was initialized unnecessarily in
>commit b8d199451c99 ("net/smc: Allow virtually contiguous sndbufs or RMBs
>for SMC-R"). Struct's field is unused in this context.
>
>Remove the assignment. No functional change intended.
>
>Suggested-by: Simon Horman <horms@kernel.org>
>Signed-off-by: Michal Luczaj <mhal@rbox.co>

Reviewed-by: Dust Li <dust.li@linux.alibaba.com>

>---
> net/smc/smc_rx.c | 1 -
> 1 file changed, 1 deletion(-)
>
>diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
>index e7f1134453ef40dd81a9574d6df4ead95acd8ae5..bbba5d4dc7eb0dbb31a9800023b0caab33e87842 100644
>--- a/net/smc/smc_rx.c
>+++ b/net/smc/smc_rx.c
>@@ -202,7 +202,6 @@ static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len,
> 			offset = 0;
> 		}
> 	}
>-	spd.nr_pages_max = nr_pages;
> 	spd.nr_pages = nr_pages;
> 	spd.pages = pages;
> 	spd.partial = partial;
>
>-- 
>2.49.0
>

[PATCH net-next v2 8/9] net: skbuff: Drop unused @skb

[Michal Luczaj]

Since its introduction in commit ce098da1497c ("skbuff: Introduce
slab_build_skb()"), __slab_build_skb() never used the @skb argument. Remove
it and adapt both callers.

No functional change intended.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/core/skbuff.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index b4f7843430a3f8f84aed387bf41ae761d97687ad..b5f685b6611c177c199f70bb16fd3940bce8cded 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -384,8 +384,7 @@ static inline void __finalize_skb_around(struct sk_buff *skb, void *data,
 	skb_set_kcov_handle(skb, kcov_common_handle());
 }
 
-static inline void *__slab_build_skb(struct sk_buff *skb, void *data,
-				     unsigned int *size)
+static inline void *__slab_build_skb(void *data, unsigned int *size)
 {
 	void *resized;
 
@@ -418,7 +417,7 @@ struct sk_buff *slab_build_skb(void *data)
 		return NULL;
 
 	memset(skb, 0, offsetof(struct sk_buff, tail));
-	data = __slab_build_skb(skb, data, &size);
+	data = __slab_build_skb(data, &size);
 	__finalize_skb_around(skb, data, size);
 
 	return skb;
@@ -435,7 +434,7 @@ static void __build_skb_around(struct sk_buff *skb, void *data,
 	 * using slab buffer should use slab_build_skb() instead.
 	 */
 	if (WARN_ONCE(size == 0, "Use slab_build_skb() instead"))
-		data = __slab_build_skb(skb, data, &size);
+		data = __slab_build_skb(data, &size);
 
 	__finalize_skb_around(skb, data, size);
 }

-- 
2.49.0

[PATCH net-next v2 9/9] net: skbuff: Drop unused @skb

[Michal Luczaj]

Since its introduction in commit 6fa01ccd8830 ("skbuff: Add pskb_extract()
helper function"), pskb_carve_frag_list() never used the argument @skb.
Drop it and adapt the only caller.

No functional change intended.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/core/skbuff.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index b5f685b6611c177c199f70bb16fd3940bce8cded..f8553c674fe5052e7c1ea53022e252a54a9d6c72 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6756,8 +6756,7 @@ static int pskb_carve(struct sk_buff *skb, const u32 off, gfp_t gfp);
 /* carve out the first eat bytes from skb's frag_list. May recurse into
  * pskb_carve()
  */
-static int pskb_carve_frag_list(struct sk_buff *skb,
-				struct skb_shared_info *shinfo, int eat,
+static int pskb_carve_frag_list(struct skb_shared_info *shinfo, int eat,
 				gfp_t gfp_mask)
 {
 	struct sk_buff *list = shinfo->frag_list;
@@ -6862,7 +6861,7 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
 		skb_clone_fraglist(skb);
 
 	/* split line is in frag list */
-	if (k == 0 && pskb_carve_frag_list(skb, shinfo, off - pos, gfp_mask)) {
+	if (k == 0 && pskb_carve_frag_list(shinfo, off - pos, gfp_mask)) {
 		/* skb_frag_unref() is not needed here as shinfo->nr_frags = 0. */
 		if (skb_has_frag_list(skb))
 			kfree_skb_list(skb_shinfo(skb)->frag_list);

-- 
2.49.0

Re: [PATCH net-next v2 9/9] net: skbuff: Drop unused @skb

[Simon Horman]

On Thu, Jun 26, 2025 at 10:33:42AM +0200, Michal Luczaj wrote:
> Since its introduction in commit 6fa01ccd8830 ("skbuff: Add pskb_extract()
> helper function"), pskb_carve_frag_list() never used the argument @skb.
> Drop it and adapt the only caller.
> 
> No functional change intended.
> 
> Signed-off-by: Michal Luczaj <mhal@rbox.co>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Jakub Kicinski]

On Thu, 26 Jun 2025 10:33:33 +0200 Michal Luczaj wrote:
> Couple of cleanup patches to get rid of unused function parameters around
> skbuff.c, plus little things spotted along the way.
> 
> Offshoot of my question in [1], but way more contained. Found by adding
> "-Wunused-parameter -Wno-error" to KBUILD_CFLAGS and grepping for specific
> skbuff.c warnings.

I feel a little ambivalent about the removal of the flags arguments.
I understand that they are unused now, but theoretically the operation
as a whole has flags so it's not crazy to pass them along.. Dunno.

Re: [PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Michal Luczaj]

On 7/1/25 03:18, Jakub Kicinski wrote:
> On Thu, 26 Jun 2025 10:33:33 +0200 Michal Luczaj wrote:
>> Couple of cleanup patches to get rid of unused function parameters around
>> skbuff.c, plus little things spotted along the way.
>>
>> Offshoot of my question in [1], but way more contained. Found by adding
>> "-Wunused-parameter -Wno-error" to KBUILD_CFLAGS and grepping for specific
>> skbuff.c warnings.
> 
> I feel a little ambivalent about the removal of the flags arguments.
> I understand that they are unused now, but theoretically the operation
> as a whole has flags so it's not crazy to pass them along.. Dunno.

I suspect you can say the same about @gfp. Even though they've both became
irrelevant for the functions that define them. But I understand your
hesitation. Should I post v3 without this/these changes?

What's netdev's stance on using __always_unused in such cases?

Thanks,
Michal

Re: [PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Paolo Abeni]

On 7/1/25 9:27 AM, Michal Luczaj wrote:
> On 7/1/25 03:18, Jakub Kicinski wrote:
>> On Thu, 26 Jun 2025 10:33:33 +0200 Michal Luczaj wrote:
>>> Couple of cleanup patches to get rid of unused function parameters around
>>> skbuff.c, plus little things spotted along the way.
>>>
>>> Offshoot of my question in [1], but way more contained. Found by adding
>>> "-Wunused-parameter -Wno-error" to KBUILD_CFLAGS and grepping for specific
>>> skbuff.c warnings.
>>
>> I feel a little ambivalent about the removal of the flags arguments.
>> I understand that they are unused now, but theoretically the operation
>> as a whole has flags so it's not crazy to pass them along.. Dunno.
> 
> I suspect you can say the same about @gfp. Even though they've both became
> irrelevant for the functions that define them. But I understand your
> hesitation. Should I post v3 without this/these changes?

Yes please, I think it would make the series less controversial.

Also I feel like the gfp flag removal is less controversial, as is IMHO
reasonable that skb_splice_from_iter() would not allocate any memory.

Thanks,

Paolo

Re: [PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Jakub Kicinski]

On Tue, 1 Jul 2025 11:02:50 +0200 Paolo Abeni wrote:
> >> I feel a little ambivalent about the removal of the flags arguments.
> >> I understand that they are unused now, but theoretically the operation
> >> as a whole has flags so it's not crazy to pass them along.. Dunno.  
> > 
> > I suspect you can say the same about @gfp. Even though they've both became
> > irrelevant for the functions that define them. But I understand your
> > hesitation. Should I post v3 without this/these changes?  
> 
> Yes please, I think it would make the series less controversial.
> 
> Also I feel like the gfp flag removal is less controversial, as is IMHO
> reasonable that skb_splice_from_iter() would not allocate any memory.

+1, FWIW, gfp flags are more as need be the callee.

> > What's netdev's stance on using __always_unused in such cases?

Subjectively, I find the unused argument warnings in the kernel
to usually be counter-productive. If a maintainer of a piece of code
wants to clean them up -- perfectly fine. But taking cleanup patches
and annotating with __always_unused doesn't see very productive.

Re: [PATCH net-next v2 0/9] net: Remove unused function parameters in skbuff.c

[Michal Luczaj]

On 7/2/25 01:52, Jakub Kicinski wrote:
> On Tue, 1 Jul 2025 11:02:50 +0200 Paolo Abeni wrote:
>>>> I feel a little ambivalent about the removal of the flags arguments.
>>>> I understand that they are unused now, but theoretically the operation
>>>> as a whole has flags so it's not crazy to pass them along.. Dunno.  
>>>
>>> I suspect you can say the same about @gfp. Even though they've both became
>>> irrelevant for the functions that define them. But I understand your
>>> hesitation. Should I post v3 without this/these changes?  
>>
>> Yes please, I think it would make the series less controversial.
>>
>> Also I feel like the gfp flag removal is less controversial, as is IMHO
>> reasonable that skb_splice_from_iter() would not allocate any memory.
> 
> +1, FWIW, gfp flags are more as need be the callee.

OK, here's v3 with @flags untouched:
https://lore.kernel.org/netdev/20250702-splice-drop-unused-v3-0-55f68b60d2b7@rbox.co/

>>> What's netdev's stance on using __always_unused in such cases?
> 
> Subjectively, I find the unused argument warnings in the kernel
> to usually be counter-productive. If a maintainer of a piece of code
> wants to clean them up -- perfectly fine. But taking cleanup patches
> and annotating with __always_unused doesn't see very productive.

Go it, thanks.

Michal