skb_splice_bits(): get rid of callback

since pipe_lock is the outermost now, we don't need to drop/regain
socket locks around the call of splice_to_pipe() from skb_splice_bits(),
which kills the need to have a socket-specific callback; we can just
call splice_to_pipe() and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

5 files changed, 6 insertions, 66 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0f665cb26b50..f520251ec43f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3021,15 +3021,9 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
 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, __wsum csum);
-ssize_t skb_socket_splice(struct sock *sk,
-                          struct pipe_inode_info *pipe,
-                          struct splice_pipe_desc *spd);
 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,
-                    ssize_t (*splice_cb)(struct sock *,
-                                         struct pipe_inode_info *,
-                                         struct splice_pipe_desc *));
+                    unsigned int flags);
 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3864b4b68fa1..208a9bc4af74 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1962,37 +1962,13 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
         return false;
 }
 
-ssize_t skb_socket_splice(struct sock *sk,
-                          struct pipe_inode_info *pipe,
-                          struct splice_pipe_desc *spd)
-{
-        int ret;
-
-        /* Drop the socket lock, otherwise we have reverse
-         * locking dependencies between sk_lock and i_mutex
-         * here as compared to sendfile(). We enter here
-         * with the socket lock held, and splice_to_pipe() will
-         * grab the pipe inode lock. For sendfile() emulation,
-         * we call into ->sendpage() with the i_mutex lock held
-         * and networking will grab the socket lock.
-         */
-        release_sock(sk);
-        ret = splice_to_pipe(pipe, spd);
-        lock_sock(sk);
-
-        return ret;
-}
-
 /*
  * Map data from the skb to a pipe. Should handle both the linear part,
  * 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,
-                    ssize_t (*splice_cb)(struct sock *,
-                                         struct pipe_inode_info *,
-                                         struct splice_pipe_desc *))
+                    unsigned int flags)
 {
         struct partial_page partial[MAX_SKB_FRAGS];
         struct page *pages[MAX_SKB_FRAGS];
@@ -2009,7 +1985,7 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
         __skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
 
         if (spd.nr_pages)
-                ret = splice_cb(sk, pipe, &spd);
+                ret = splice_to_pipe(pipe, &spd);
 
         return ret;
 }
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ffbb218de520..ddd2179538f7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -688,8 +688,7 @@ 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,
-                              skb_socket_splice);
+                              min(rd_desc->count, len), tss->flags);
         if (ret > 0)
                 rd_desc->count -= ret;
         return ret;
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 411693288648..8a720ba50061 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1462,19 +1462,6 @@ out:
         return copied ? : err;
 }
 
-static ssize_t kcm_sock_splice(struct sock *sk,
-                               struct pipe_inode_info *pipe,
-                               struct splice_pipe_desc *spd)
-{
-        int ret;
-
-        release_sock(sk);
-        ret = splice_to_pipe(pipe, spd);
-        lock_sock(sk);
-
-        return ret;
-}
-
 static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
                                struct pipe_inode_info *pipe, size_t len,
                                unsigned int flags)
@@ -1504,8 +1491,7 @@ static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
         if (len > rxm->full_len)
                 len = rxm->full_len;
 
-        copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
-                                 kcm_sock_splice);
+        copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags);
         if (copied < 0) {
                 err = copied;
                 goto err_out;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 8309687a56b0..145082e2ba36 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2475,28 +2475,13 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
         return unix_stream_read_generic(&state);
 }
 
-static ssize_t skb_unix_socket_splice(struct sock *sk,
-                                      struct pipe_inode_info *pipe,
-                                      struct splice_pipe_desc *spd)
-{
-        int ret;
-        struct unix_sock *u = unix_sk(sk);
-
-        mutex_unlock(&u->iolock);
-        ret = splice_to_pipe(pipe, spd);
-        mutex_lock(&u->iolock);
-
-        return ret;
-}
-
 static int unix_stream_splice_actor(struct sk_buff *skb,
                                     int skip, int chunk,
                                     struct unix_stream_read_state *state)
 {
         return skb_splice_bits(skb, state->socket->sk,
                                UNIXCB(skb).consumed + skip,
-                               state->pipe, chunk, state->splice_flags,
-                               skb_unix_socket_splice);
+                               state->pipe, chunk, state->splice_flags);
 }
 
 static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,