net: remove sock_iocb

The sock_iocb structure is allocate on stack for each read/write-like
operation on sockets, and contains various fields of which only the
embedded msghdr and sometimes a pointer to the scm_cookie is ever used.
Get rid of the sock_iocb and put a msghdr directly on the stack and pass
the scm_cookie explicitly to netlink_mmap_sendmsg.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sock.h b/include/net/sock.h
index 2210fec..1534149 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1374,29 +1374,6 @@ void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
 #define SOCK_BINDADDR_LOCK     4
 #define SOCK_BINDPORT_LOCK     8
 
-/* sock_iocb: used to kick off async processing of socket ios */
-struct sock_iocb {
-       struct list_head        list;
-
-       int                     flags;
-       int                     size;
-       struct socket           *sock;
-       struct sock             *sk;
-       struct scm_cookie       *scm;
-       struct msghdr           *msg, async_msg;
-       struct kiocb            *kiocb;
-};
-
-static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
-{
-       return (struct sock_iocb *)iocb->private;
-}
-
-static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
-{
-       return si->kiocb;
-}
-
 struct socket_alloc {
        struct socket socket;
        struct inode vfs_inode;

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 2197af0..a36777b 100644 (file)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -695,7 +695,7 @@ static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
 
 static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
                                u32 dst_portid, u32 dst_group,
-                               struct sock_iocb *siocb)
+                               struct scm_cookie *scm)
 {
        struct netlink_sock *nlk = nlk_sk(sk);
        struct netlink_ring *ring;
@@ -741,7 +741,7 @@ static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
 
                NETLINK_CB(skb).portid    = nlk->portid;
                NETLINK_CB(skb).dst_group = dst_group;
-               NETLINK_CB(skb).creds     = siocb->scm->creds;
+               NETLINK_CB(skb).creds     = scm->creds;
 
                err = security_netlink_send(sk, skb);
                if (err) {
@@ -820,7 +820,7 @@ static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
 #define netlink_tx_is_mmaped(sk)       false
 #define netlink_mmap                   sock_no_mmap
 #define netlink_poll                   datagram_poll
-#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb)    0
+#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, scm)      0
 #endif /* CONFIG_NETLINK_MMAP */
 
 static void netlink_skb_destructor(struct sk_buff *skb)
@@ -2259,7 +2259,6 @@ static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
                           struct msghdr *msg, size_t len)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
        struct sock *sk = sock->sk;
        struct netlink_sock *nlk = nlk_sk(sk);
        DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
@@ -2273,10 +2272,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
        if (msg->msg_flags&MSG_OOB)
                return -EOPNOTSUPP;
 
-       if (NULL == siocb->scm)
-               siocb->scm = &scm;
-
-       err = scm_send(sock, msg, siocb->scm, true);
+       err = scm_send(sock, msg, &scm, true);
        if (err < 0)
                return err;
 
@@ -2305,7 +2301,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
        if (netlink_tx_is_mmaped(sk) &&
            msg->msg_iter.iov->iov_base == NULL) {
                err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
-                                          siocb);
+                                          &scm);
                goto out;
        }
 
@@ -2319,7 +2315,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
 
        NETLINK_CB(skb).portid  = nlk->portid;
        NETLINK_CB(skb).dst_group = dst_group;
-       NETLINK_CB(skb).creds   = siocb->scm->creds;
+       NETLINK_CB(skb).creds   = scm.creds;
        NETLINK_CB(skb).flags   = netlink_skb_flags;
 
        err = -EFAULT;
@@ -2341,7 +2337,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
        err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
 
 out:
-       scm_destroy(siocb->scm);
+       scm_destroy(&scm);
        return err;
 }
 
@@ -2349,7 +2345,6 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
                           struct msghdr *msg, size_t len,
                           int flags)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
        struct scm_cookie scm;
        struct sock *sk = sock->sk;
        struct netlink_sock *nlk = nlk_sk(sk);
@@ -2412,11 +2407,8 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
        if (nlk->flags & NETLINK_RECV_PKTINFO)
                netlink_cmsg_recv_pktinfo(msg, skb);
 
-       if (NULL == siocb->scm) {
-               memset(&scm, 0, sizeof(scm));
-               siocb->scm = &scm;
-       }
-       siocb->scm->creds = *NETLINK_CREDS(skb);
+       memset(&scm, 0, sizeof(scm));
+       scm.creds = *NETLINK_CREDS(skb);
        if (flags & MSG_TRUNC)
                copied = data_skb->len;
 
@@ -2431,7 +2423,7 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
                }
        }
 
-       scm_recv(sock, msg, siocb->scm, flags);
+       scm_recv(sock, msg, &scm, flags);
 out:
        netlink_rcv_wake(sk);
        return err ? : copied;

diff --git a/net/socket.c b/net/socket.c
index 3acd35f..3326d67 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -613,13 +613,6 @@ EXPORT_SYMBOL(__sock_tx_timestamp);
 static inline int __sock_sendmsg_nosec(struct kiocb *iocb, struct socket *sock,
                                       struct msghdr *msg, size_t size)
 {
-       struct sock_iocb *si = kiocb_to_siocb(iocb);
-
-       si->sock = sock;
-       si->scm = NULL;
-       si->msg = msg;
-       si->size = size;
-
        return sock->ops->sendmsg(iocb, sock, msg, size);
 }
 
@@ -635,11 +628,9 @@ static int do_sock_sendmsg(struct socket *sock, struct msghdr *msg,
                           size_t size, bool nosec)
 {
        struct kiocb iocb;
-       struct sock_iocb siocb;
        int ret;
 
        init_sync_kiocb(&iocb, NULL);
-       iocb.private = &siocb;
        ret = nosec ? __sock_sendmsg_nosec(&iocb, sock, msg, size) :
                      __sock_sendmsg(&iocb, sock, msg, size);
        if (-EIOCBQUEUED == ret)
@@ -756,14 +747,6 @@ EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);
 static inline int __sock_recvmsg_nosec(struct kiocb *iocb, struct socket *sock,
                                       struct msghdr *msg, size_t size, int flags)
 {
-       struct sock_iocb *si = kiocb_to_siocb(iocb);
-
-       si->sock = sock;
-       si->scm = NULL;
-       si->msg = msg;
-       si->size = size;
-       si->flags = flags;
-
        return sock->ops->recvmsg(iocb, sock, msg, size, flags);
 }
 
@@ -779,11 +762,9 @@ int sock_recvmsg(struct socket *sock, struct msghdr *msg,
                 size_t size, int flags)
 {
        struct kiocb iocb;
-       struct sock_iocb siocb;
        int ret;
 
        init_sync_kiocb(&iocb, NULL);
-       iocb.private = &siocb;
        ret = __sock_recvmsg(&iocb, sock, msg, size, flags);
        if (-EIOCBQUEUED == ret)
                ret = wait_on_sync_kiocb(&iocb);
@@ -795,11 +776,9 @@ static int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
                              size_t size, int flags)
 {
        struct kiocb iocb;
-       struct sock_iocb siocb;
        int ret;
 
        init_sync_kiocb(&iocb, NULL);
-       iocb.private = &siocb;
        ret = __sock_recvmsg_nosec(&iocb, sock, msg, size, flags);
        if (-EIOCBQUEUED == ret)
                ret = wait_on_sync_kiocb(&iocb);
@@ -866,14 +845,6 @@ static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
        return sock->ops->splice_read(sock, ppos, pipe, len, flags);
 }
 
-static struct sock_iocb *alloc_sock_iocb(struct kiocb *iocb,
-                                        struct sock_iocb *siocb)
-{
-       siocb->kiocb = iocb;
-       iocb->private = siocb;
-       return siocb;
-}
-
 static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,
                struct file *file, const struct iovec *iov,
                unsigned long nr_segs)
@@ -893,7 +864,7 @@ static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,
 static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
                                unsigned long nr_segs, loff_t pos)
 {
-       struct sock_iocb siocb, *x;
+       struct msghdr msg;
 
        if (pos != 0)
                return -ESPIPE;
@@ -901,11 +872,7 @@ static ssize_t sock_aio_read(struct kiocb *iocb, const struct iovec *iov,
        if (iocb->ki_nbytes == 0)       /* Match SYS5 behaviour */
                return 0;
 
-
-       x = alloc_sock_iocb(iocb, &siocb);
-       if (!x)
-               return -ENOMEM;
-       return do_sock_read(&x->async_msg, iocb, iocb->ki_filp, iov, nr_segs);
+       return do_sock_read(&msg, iocb, iocb->ki_filp, iov, nr_segs);
 }
 
 static ssize_t do_sock_write(struct msghdr *msg, struct kiocb *iocb,
@@ -929,16 +896,12 @@ static ssize_t do_sock_write(struct msghdr *msg, struct kiocb *iocb,
 static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov,
                          unsigned long nr_segs, loff_t pos)
 {
-       struct sock_iocb siocb, *x;
+       struct msghdr msg;
 
        if (pos != 0)
                return -ESPIPE;
 
-       x = alloc_sock_iocb(iocb, &siocb);
-       if (!x)
-               return -ENOMEM;
-
-       return do_sock_write(&x->async_msg, iocb, iocb->ki_filp, iov, nr_segs);
+       return do_sock_write(&msg, iocb, iocb->ki_filp, iov, nr_segs);
 }
 
 /*

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 8e1b102..526b6ed 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1445,7 +1445,6 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
 static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
                              struct msghdr *msg, size_t len)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
        struct sock *sk = sock->sk;
        struct net *net = sock_net(sk);
        struct unix_sock *u = unix_sk(sk);
@@ -1456,14 +1455,12 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
        unsigned int hash;
        struct sk_buff *skb;
        long timeo;
-       struct scm_cookie tmp_scm;
+       struct scm_cookie scm;
        int max_level;
        int data_len = 0;
 
-       if (NULL == siocb->scm)
-               siocb->scm = &tmp_scm;
        wait_for_unix_gc();
-       err = scm_send(sock, msg, siocb->scm, false);
+       err = scm_send(sock, msg, &scm, false);
        if (err < 0)
                return err;
 
@@ -1507,11 +1504,11 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
        if (skb == NULL)
                goto out;
 
-       err = unix_scm_to_skb(siocb->scm, skb, true);
+       err = unix_scm_to_skb(&scm, skb, true);
        if (err < 0)
                goto out_free;
        max_level = err + 1;
-       unix_get_secdata(siocb->scm, skb);
+       unix_get_secdata(&scm, skb);
 
        skb_put(skb, len - data_len);
        skb->data_len = data_len;
@@ -1606,7 +1603,7 @@ restart:
        unix_state_unlock(other);
        other->sk_data_ready(other);
        sock_put(other);
-       scm_destroy(siocb->scm);
+       scm_destroy(&scm);
        return len;
 
 out_unlock:
@@ -1616,7 +1613,7 @@ out_free:
 out:
        if (other)
                sock_put(other);
-       scm_destroy(siocb->scm);
+       scm_destroy(&scm);
        return err;
 }
 
@@ -1628,21 +1625,18 @@ out:
 static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                               struct msghdr *msg, size_t len)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
        struct sock *sk = sock->sk;
        struct sock *other = NULL;
        int err, size;
        struct sk_buff *skb;
        int sent = 0;
-       struct scm_cookie tmp_scm;
+       struct scm_cookie scm;
        bool fds_sent = false;
        int max_level;
        int data_len;
 
-       if (NULL == siocb->scm)
-               siocb->scm = &tmp_scm;
        wait_for_unix_gc();
-       err = scm_send(sock, msg, siocb->scm, false);
+       err = scm_send(sock, msg, &scm, false);
        if (err < 0)
                return err;
 
@@ -1683,7 +1677,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                        goto out_err;
 
                /* Only send the fds in the first buffer */
-               err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
+               err = unix_scm_to_skb(&scm, skb, !fds_sent);
                if (err < 0) {
                        kfree_skb(skb);
                        goto out_err;
@@ -1715,8 +1709,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                sent += size;
        }
 
-       scm_destroy(siocb->scm);
-       siocb->scm = NULL;
+       scm_destroy(&scm);
 
        return sent;
 
@@ -1728,8 +1721,7 @@ pipe_err:
                send_sig(SIGPIPE, current, 0);
        err = -EPIPE;
 out_err:
-       scm_destroy(siocb->scm);
-       siocb->scm = NULL;
+       scm_destroy(&scm);
        return sent ? : err;
 }
 
@@ -1778,8 +1770,7 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
                              struct msghdr *msg, size_t size,
                              int flags)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(iocb);
-       struct scm_cookie tmp_scm;
+       struct scm_cookie scm;
        struct sock *sk = sock->sk;
        struct unix_sock *u = unix_sk(sk);
        int noblock = flags & MSG_DONTWAIT;
@@ -1831,16 +1822,14 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
        if (sock_flag(sk, SOCK_RCVTSTAMP))
                __sock_recv_timestamp(msg, sk, skb);
 
-       if (!siocb->scm) {
-               siocb->scm = &tmp_scm;
-               memset(&tmp_scm, 0, sizeof(tmp_scm));
-       }
-       scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
-       unix_set_secdata(siocb->scm, skb);
+       memset(&scm, 0, sizeof(scm));
+
+       scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
+       unix_set_secdata(&scm, skb);
 
        if (!(flags & MSG_PEEK)) {
                if (UNIXCB(skb).fp)
-                       unix_detach_fds(siocb->scm, skb);
+                       unix_detach_fds(&scm, skb);
 
                sk_peek_offset_bwd(sk, skb->len);
        } else {
@@ -1860,11 +1849,11 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
                sk_peek_offset_fwd(sk, size);
 
                if (UNIXCB(skb).fp)
-                       siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
+                       scm.fp = scm_fp_dup(UNIXCB(skb).fp);
        }
        err = (flags & MSG_TRUNC) ? skb->len - skip : size;
 
-       scm_recv(sock, msg, siocb->scm, flags);
+       scm_recv(sock, msg, &scm, flags);
 
 out_free:
        skb_free_datagram(sk, skb);
@@ -1915,8 +1904,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
                               struct msghdr *msg, size_t size,
                               int flags)
 {
-       struct sock_iocb *siocb = kiocb_to_siocb(iocb);
-       struct scm_cookie tmp_scm;
+       struct scm_cookie scm;
        struct sock *sk = sock->sk;
        struct unix_sock *u = unix_sk(sk);
        DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
@@ -1943,10 +1931,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
         * while sleeps in memcpy_tomsg
         */
 
-       if (!siocb->scm) {
-               siocb->scm = &tmp_scm;
-               memset(&tmp_scm, 0, sizeof(tmp_scm));
-       }
+       memset(&scm, 0, sizeof(scm));
 
        err = mutex_lock_interruptible(&u->readlock);
        if (unlikely(err)) {
@@ -2012,13 +1997,13 @@ again:
 
                if (check_creds) {
                        /* Never glue messages from different writers */
-                       if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
-                           !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
-                           !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
+                       if ((UNIXCB(skb).pid  != scm.pid) ||
+                           !uid_eq(UNIXCB(skb).uid, scm.creds.uid) ||
+                           !gid_eq(UNIXCB(skb).gid, scm.creds.gid))
                                break;
                } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
                        /* Copy credentials */
-                       scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
+                       scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
                        check_creds = 1;
                }
 
@@ -2045,7 +2030,7 @@ again:
                        sk_peek_offset_bwd(sk, chunk);
 
                        if (UNIXCB(skb).fp)
-                               unix_detach_fds(siocb->scm, skb);
+                               unix_detach_fds(&scm, skb);
 
                        if (unix_skb_len(skb))
                                break;
@@ -2053,13 +2038,13 @@ again:
                        skb_unlink(skb, &sk->sk_receive_queue);
                        consume_skb(skb);
 
-                       if (siocb->scm->fp)
+                       if (scm.fp)
                                break;
                } else {
                        /* It is questionable, see note in unix_dgram_recvmsg.
                         */
                        if (UNIXCB(skb).fp)
-                               siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
+                               scm.fp = scm_fp_dup(UNIXCB(skb).fp);
 
                        sk_peek_offset_fwd(sk, chunk);
 
@@ -2068,7 +2053,7 @@ again:
        } while (size);
 
        mutex_unlock(&u->readlock);
-       scm_recv(sock, msg, siocb->scm, flags);
+       scm_recv(sock, msg, &scm, flags);
 out:
        return copied ? : err;
 }