Index: head/sys/kern/sys_socket.c
===================================================================
--- head/sys/kern/sys_socket.c	(revision 359183)
+++ head/sys/kern/sys_socket.c	(revision 359184)
@@ -1,823 +1,824 @@
 /*-
  * SPDX-License-Identifier: BSD-3-Clause
  *
  * Copyright (c) 1982, 1986, 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  *	@(#)sys_socket.c	8.1 (Berkeley) 6/10/93
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/aio.h>
 #include <sys/domain.h>
 #include <sys/file.h>
 #include <sys/filedesc.h>
 #include <sys/kernel.h>
 #include <sys/kthread.h>
 #include <sys/malloc.h>
 #include <sys/proc.h>
 #include <sys/protosw.h>
 #include <sys/sigio.h>
 #include <sys/signal.h>
 #include <sys/signalvar.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/filio.h>			/* XXX */
 #include <sys/sockio.h>
 #include <sys/stat.h>
 #include <sys/sysctl.h>
 #include <sys/sysproto.h>
 #include <sys/taskqueue.h>
 #include <sys/uio.h>
 #include <sys/ucred.h>
 #include <sys/un.h>
 #include <sys/unpcb.h>
 #include <sys/user.h>
 
 #include <net/if.h>
 #include <net/if_var.h>
 #include <net/route.h>
 #include <net/vnet.h>
 
 #include <netinet/in.h>
 #include <netinet/in_pcb.h>
 
 #include <security/mac/mac_framework.h>
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
 #include <vm/vm_extern.h>
 #include <vm/vm_map.h>
 
 static SYSCTL_NODE(_kern_ipc, OID_AUTO, aio, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
     "socket AIO stats");
 
 static int empty_results;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_results, CTLFLAG_RD, &empty_results,
     0, "socket operation returned EAGAIN");
 
 static int empty_retries;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_retries, CTLFLAG_RD, &empty_retries,
     0, "socket operation retries");
 
 static fo_rdwr_t soo_read;
 static fo_rdwr_t soo_write;
 static fo_ioctl_t soo_ioctl;
 static fo_poll_t soo_poll;
 extern fo_kqfilter_t soo_kqfilter;
 static fo_stat_t soo_stat;
 static fo_close_t soo_close;
 static fo_fill_kinfo_t soo_fill_kinfo;
 static fo_aio_queue_t soo_aio_queue;
 
 static void	soo_aio_cancel(struct kaiocb *job);
 
 struct fileops	socketops = {
 	.fo_read = soo_read,
 	.fo_write = soo_write,
 	.fo_truncate = invfo_truncate,
 	.fo_ioctl = soo_ioctl,
 	.fo_poll = soo_poll,
 	.fo_kqfilter = soo_kqfilter,
 	.fo_stat = soo_stat,
 	.fo_close = soo_close,
 	.fo_chmod = invfo_chmod,
 	.fo_chown = invfo_chown,
 	.fo_sendfile = invfo_sendfile,
 	.fo_fill_kinfo = soo_fill_kinfo,
 	.fo_aio_queue = soo_aio_queue,
 	.fo_flags = DFLAG_PASSABLE
 };
 
 static int
 soo_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
     int flags, struct thread *td)
 {
 	struct socket *so = fp->f_data;
 	int error;
 
 #ifdef MAC
 	error = mac_socket_check_receive(active_cred, so);
 	if (error)
 		return (error);
 #endif
 	error = soreceive(so, 0, uio, 0, 0, 0);
 	return (error);
 }
 
 static int
 soo_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
     int flags, struct thread *td)
 {
 	struct socket *so = fp->f_data;
 	int error;
 
 #ifdef MAC
 	error = mac_socket_check_send(active_cred, so);
 	if (error)
 		return (error);
 #endif
 	error = sosend(so, 0, uio, 0, 0, 0, uio->uio_td);
 	if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
 		PROC_LOCK(uio->uio_td->td_proc);
 		tdsignal(uio->uio_td, SIGPIPE);
 		PROC_UNLOCK(uio->uio_td->td_proc);
 	}
 	return (error);
 }
 
 static int
 soo_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred,
     struct thread *td)
 {
 	struct socket *so = fp->f_data;
 	int error = 0;
 
 	switch (cmd) {
 	case FIONBIO:
 		SOCK_LOCK(so);
 		if (*(int *)data)
 			so->so_state |= SS_NBIO;
 		else
 			so->so_state &= ~SS_NBIO;
 		SOCK_UNLOCK(so);
 		break;
 
 	case FIOASYNC:
 		if (*(int *)data) {
 			SOCK_LOCK(so);
 			so->so_state |= SS_ASYNC;
 			if (SOLISTENING(so)) {
 				so->sol_sbrcv_flags |= SB_ASYNC;
 				so->sol_sbsnd_flags |= SB_ASYNC;
 			} else {
 				SOCKBUF_LOCK(&so->so_rcv);
 				so->so_rcv.sb_flags |= SB_ASYNC;
 				SOCKBUF_UNLOCK(&so->so_rcv);
 				SOCKBUF_LOCK(&so->so_snd);
 				so->so_snd.sb_flags |= SB_ASYNC;
 				SOCKBUF_UNLOCK(&so->so_snd);
 			}
 			SOCK_UNLOCK(so);
 		} else {
 			SOCK_LOCK(so);
 			so->so_state &= ~SS_ASYNC;
 			if (SOLISTENING(so)) {
 				so->sol_sbrcv_flags &= ~SB_ASYNC;
 				so->sol_sbsnd_flags &= ~SB_ASYNC;
 			} else {
 				SOCKBUF_LOCK(&so->so_rcv);
 				so->so_rcv.sb_flags &= ~SB_ASYNC;
 				SOCKBUF_UNLOCK(&so->so_rcv);
 				SOCKBUF_LOCK(&so->so_snd);
 				so->so_snd.sb_flags &= ~SB_ASYNC;
 				SOCKBUF_UNLOCK(&so->so_snd);
 			}
 			SOCK_UNLOCK(so);
 		}
 		break;
 
 	case FIONREAD:
 		/* Unlocked read. */
 		*(int *)data = sbavail(&so->so_rcv);
 		break;
 
 	case FIONWRITE:
 		/* Unlocked read. */
 		*(int *)data = sbavail(&so->so_snd);
 		break;
 
 	case FIONSPACE:
 		/* Unlocked read. */
 		if ((so->so_snd.sb_hiwat < sbused(&so->so_snd)) ||
 		    (so->so_snd.sb_mbmax < so->so_snd.sb_mbcnt))
 			*(int *)data = 0;
 		else
 			*(int *)data = sbspace(&so->so_snd);
 		break;
 
 	case FIOSETOWN:
 		error = fsetown(*(int *)data, &so->so_sigio);
 		break;
 
 	case FIOGETOWN:
 		*(int *)data = fgetown(&so->so_sigio);
 		break;
 
 	case SIOCSPGRP:
 		error = fsetown(-(*(int *)data), &so->so_sigio);
 		break;
 
 	case SIOCGPGRP:
 		*(int *)data = -fgetown(&so->so_sigio);
 		break;
 
 	case SIOCATMARK:
 		/* Unlocked read. */
 		*(int *)data = (so->so_rcv.sb_state & SBS_RCVATMARK) != 0;
 		break;
 	default:
 		/*
 		 * Interface/routing/protocol specific ioctls: interface and
 		 * routing ioctls should have a different entry since a
 		 * socket is unnecessary.
 		 */
 		if (IOCGROUP(cmd) == 'i')
 			error = ifioctl(so, cmd, data, td);
 		else if (IOCGROUP(cmd) == 'r') {
 			CURVNET_SET(so->so_vnet);
 			error = rtioctl_fib(cmd, data, so->so_fibnum);
 			CURVNET_RESTORE();
 		} else {
 			CURVNET_SET(so->so_vnet);
 			error = ((*so->so_proto->pr_usrreqs->pru_control)
 			    (so, cmd, data, 0, td));
 			CURVNET_RESTORE();
 		}
 		break;
 	}
 	return (error);
 }
 
 static int
 soo_poll(struct file *fp, int events, struct ucred *active_cred,
     struct thread *td)
 {
 	struct socket *so = fp->f_data;
 #ifdef MAC
 	int error;
 
 	error = mac_socket_check_poll(active_cred, so);
 	if (error)
 		return (error);
 #endif
 	return (sopoll(so, events, fp->f_cred, td));
 }
 
 static int
 soo_stat(struct file *fp, struct stat *ub, struct ucred *active_cred,
     struct thread *td)
 {
 	struct socket *so = fp->f_data;
-#ifdef MAC
 	int error;
-#endif
 
 	bzero((caddr_t)ub, sizeof (*ub));
 	ub->st_mode = S_IFSOCK;
 #ifdef MAC
 	error = mac_socket_check_stat(active_cred, so);
 	if (error)
 		return (error);
 #endif
+	SOCK_LOCK(so);
 	if (!SOLISTENING(so)) {
 		struct sockbuf *sb;
 
 		/*
 		 * If SBS_CANTRCVMORE is set, but there's still data left
 		 * in the receive buffer, the socket is still readable.
 		 */
 		sb = &so->so_rcv;
 		SOCKBUF_LOCK(sb);
 		if ((sb->sb_state & SBS_CANTRCVMORE) == 0 || sbavail(sb))
 			ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
 		ub->st_size = sbavail(sb) - sb->sb_ctl;
 		SOCKBUF_UNLOCK(sb);
 	
 		sb = &so->so_snd;
 		SOCKBUF_LOCK(sb);
 		if ((sb->sb_state & SBS_CANTSENDMORE) == 0)
 			ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
 		SOCKBUF_UNLOCK(sb);
 	}
 	ub->st_uid = so->so_cred->cr_uid;
 	ub->st_gid = so->so_cred->cr_gid;
-	return (*so->so_proto->pr_usrreqs->pru_sense)(so, ub);
+	error = so->so_proto->pr_usrreqs->pru_sense(so, ub);
+	SOCK_UNLOCK(so);
+	return (error);
 }
 
 /*
  * API socket close on file pointer.  We call soclose() to close the socket
  * (including initiating closing protocols).  soclose() will sorele() the
  * file reference but the actual socket will not go away until the socket's
  * ref count hits 0.
  */
 static int
 soo_close(struct file *fp, struct thread *td)
 {
 	int error = 0;
 	struct socket *so;
 
 	so = fp->f_data;
 	fp->f_ops = &badfileops;
 	fp->f_data = NULL;
 
 	if (so)
 		error = soclose(so);
 	return (error);
 }
 
 static int
 soo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
 {
 	struct sockaddr *sa;
 	struct inpcb *inpcb;
 	struct unpcb *unpcb;
 	struct socket *so;
 	int error;
 
 	kif->kf_type = KF_TYPE_SOCKET;
 	so = fp->f_data;
 	CURVNET_SET(so->so_vnet);
 	kif->kf_un.kf_sock.kf_sock_domain0 =
 	    so->so_proto->pr_domain->dom_family;
 	kif->kf_un.kf_sock.kf_sock_type0 = so->so_type;
 	kif->kf_un.kf_sock.kf_sock_protocol0 = so->so_proto->pr_protocol;
 	kif->kf_un.kf_sock.kf_sock_pcb = (uintptr_t)so->so_pcb;
 	switch (kif->kf_un.kf_sock.kf_sock_domain0) {
 	case AF_INET:
 	case AF_INET6:
 		if (kif->kf_un.kf_sock.kf_sock_protocol0 == IPPROTO_TCP) {
 			if (so->so_pcb != NULL) {
 				inpcb = (struct inpcb *)(so->so_pcb);
 				kif->kf_un.kf_sock.kf_sock_inpcb =
 				    (uintptr_t)inpcb->inp_ppcb;
 				kif->kf_un.kf_sock.kf_sock_sendq =
 				    sbused(&so->so_snd);
 				kif->kf_un.kf_sock.kf_sock_recvq =
 				    sbused(&so->so_rcv);
 			}
 		}
 		break;
 	case AF_UNIX:
 		if (so->so_pcb != NULL) {
 			unpcb = (struct unpcb *)(so->so_pcb);
 			if (unpcb->unp_conn) {
 				kif->kf_un.kf_sock.kf_sock_unpconn =
 				    (uintptr_t)unpcb->unp_conn;
 				kif->kf_un.kf_sock.kf_sock_rcv_sb_state =
 				    so->so_rcv.sb_state;
 				kif->kf_un.kf_sock.kf_sock_snd_sb_state =
 				    so->so_snd.sb_state;
 				kif->kf_un.kf_sock.kf_sock_sendq =
 				    sbused(&so->so_snd);
 				kif->kf_un.kf_sock.kf_sock_recvq =
 				    sbused(&so->so_rcv);
 			}
 		}
 		break;
 	}
 	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
 	if (error == 0 &&
 	    sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_local)) {
 		bcopy(sa, &kif->kf_un.kf_sock.kf_sa_local, sa->sa_len);
 		free(sa, M_SONAME);
 	}
 	error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
 	if (error == 0 &&
 	    sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_peer)) {
 		bcopy(sa, &kif->kf_un.kf_sock.kf_sa_peer, sa->sa_len);
 		free(sa, M_SONAME);
 	}
 	strncpy(kif->kf_path, so->so_proto->pr_domain->dom_name,
 	    sizeof(kif->kf_path));
 	CURVNET_RESTORE();
 	return (0);	
 }
 
 /*
  * Use the 'backend3' field in AIO jobs to store the amount of data
  * completed by the AIO job so far.
  */
 #define	aio_done	backend3
 
 static STAILQ_HEAD(, task) soaio_jobs;
 static struct mtx soaio_jobs_lock;
 static struct task soaio_kproc_task;
 static int soaio_starting, soaio_idle, soaio_queued;
 static struct unrhdr *soaio_kproc_unr;
 
 static int soaio_max_procs = MAX_AIO_PROCS;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, max_procs, CTLFLAG_RW, &soaio_max_procs, 0,
     "Maximum number of kernel processes to use for async socket IO");
 
 static int soaio_num_procs;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, num_procs, CTLFLAG_RD, &soaio_num_procs, 0,
     "Number of active kernel processes for async socket IO");
 
 static int soaio_target_procs = TARGET_AIO_PROCS;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, target_procs, CTLFLAG_RD,
     &soaio_target_procs, 0,
     "Preferred number of ready kernel processes for async socket IO");
 
 static int soaio_lifetime;
 SYSCTL_INT(_kern_ipc_aio, OID_AUTO, lifetime, CTLFLAG_RW, &soaio_lifetime, 0,
     "Maximum lifetime for idle aiod");
 
 static void
 soaio_kproc_loop(void *arg)
 {
 	struct proc *p;
 	struct vmspace *myvm;
 	struct task *task;
 	int error, id, pending;
 
 	id = (intptr_t)arg;
 
 	/*
 	 * Grab an extra reference on the daemon's vmspace so that it
 	 * doesn't get freed by jobs that switch to a different
 	 * vmspace.
 	 */
 	p = curproc;
 	myvm = vmspace_acquire_ref(p);
 
 	mtx_lock(&soaio_jobs_lock);
 	MPASS(soaio_starting > 0);
 	soaio_starting--;
 	for (;;) {
 		while (!STAILQ_EMPTY(&soaio_jobs)) {
 			task = STAILQ_FIRST(&soaio_jobs);
 			STAILQ_REMOVE_HEAD(&soaio_jobs, ta_link);
 			soaio_queued--;
 			pending = task->ta_pending;
 			task->ta_pending = 0;
 			mtx_unlock(&soaio_jobs_lock);
 
 			task->ta_func(task->ta_context, pending);
 
 			mtx_lock(&soaio_jobs_lock);
 		}
 		MPASS(soaio_queued == 0);
 
 		if (p->p_vmspace != myvm) {
 			mtx_unlock(&soaio_jobs_lock);
 			vmspace_switch_aio(myvm);
 			mtx_lock(&soaio_jobs_lock);
 			continue;
 		}
 
 		soaio_idle++;
 		error = mtx_sleep(&soaio_idle, &soaio_jobs_lock, 0, "-",
 		    soaio_lifetime);
 		soaio_idle--;
 		if (error == EWOULDBLOCK && STAILQ_EMPTY(&soaio_jobs) &&
 		    soaio_num_procs > soaio_target_procs)
 			break;
 	}
 	soaio_num_procs--;
 	mtx_unlock(&soaio_jobs_lock);
 	free_unr(soaio_kproc_unr, id);
 	kproc_exit(0);
 }
 
 static void
 soaio_kproc_create(void *context, int pending)
 {
 	struct proc *p;
 	int error, id;
 
 	mtx_lock(&soaio_jobs_lock);
 	for (;;) {
 		if (soaio_num_procs < soaio_target_procs) {
 			/* Must create */
 		} else if (soaio_num_procs >= soaio_max_procs) {
 			/*
 			 * Hit the limit on kernel processes, don't
 			 * create another one.
 			 */
 			break;
 		} else if (soaio_queued <= soaio_idle + soaio_starting) {
 			/*
 			 * No more AIO jobs waiting for a process to be
 			 * created, so stop.
 			 */
 			break;
 		}
 		soaio_starting++;
 		mtx_unlock(&soaio_jobs_lock);
 
 		id = alloc_unr(soaio_kproc_unr);
 		error = kproc_create(soaio_kproc_loop, (void *)(intptr_t)id,
 		    &p, 0, 0, "soaiod%d", id);
 		if (error != 0) {
 			free_unr(soaio_kproc_unr, id);
 			mtx_lock(&soaio_jobs_lock);
 			soaio_starting--;
 			break;
 		}
 
 		mtx_lock(&soaio_jobs_lock);
 		soaio_num_procs++;
 	}
 	mtx_unlock(&soaio_jobs_lock);
 }
 
 void
 soaio_enqueue(struct task *task)
 {
 
 	mtx_lock(&soaio_jobs_lock);
 	MPASS(task->ta_pending == 0);
 	task->ta_pending++;
 	STAILQ_INSERT_TAIL(&soaio_jobs, task, ta_link);
 	soaio_queued++;
 	if (soaio_queued <= soaio_idle)
 		wakeup_one(&soaio_idle);
 	else if (soaio_num_procs < soaio_max_procs)
 		taskqueue_enqueue(taskqueue_thread, &soaio_kproc_task);
 	mtx_unlock(&soaio_jobs_lock);
 }
 
 static void
 soaio_init(void)
 {
 
 	soaio_lifetime = AIOD_LIFETIME_DEFAULT;
 	STAILQ_INIT(&soaio_jobs);
 	mtx_init(&soaio_jobs_lock, "soaio jobs", NULL, MTX_DEF);
 	soaio_kproc_unr = new_unrhdr(1, INT_MAX, NULL);
 	TASK_INIT(&soaio_kproc_task, 0, soaio_kproc_create, NULL);
 	if (soaio_target_procs > 0)
 		taskqueue_enqueue(taskqueue_thread, &soaio_kproc_task);
 }
 SYSINIT(soaio, SI_SUB_VFS, SI_ORDER_ANY, soaio_init, NULL);
 
 static __inline int
 soaio_ready(struct socket *so, struct sockbuf *sb)
 {
 	return (sb == &so->so_rcv ? soreadable(so) : sowriteable(so));
 }
 
 static void
 soaio_process_job(struct socket *so, struct sockbuf *sb, struct kaiocb *job)
 {
 	struct ucred *td_savedcred;
 	struct thread *td;
 	struct file *fp;
 	struct uio uio;
 	struct iovec iov;
 	size_t cnt, done;
 	long ru_before;
 	int error, flags;
 
 	SOCKBUF_UNLOCK(sb);
 	aio_switch_vmspace(job);
 	td = curthread;
 	fp = job->fd_file;
 retry:
 	td_savedcred = td->td_ucred;
 	td->td_ucred = job->cred;
 
 	done = job->aio_done;
 	cnt = job->uaiocb.aio_nbytes - done;
 	iov.iov_base = (void *)((uintptr_t)job->uaiocb.aio_buf + done);
 	iov.iov_len = cnt;
 	uio.uio_iov = &iov;
 	uio.uio_iovcnt = 1;
 	uio.uio_offset = 0;
 	uio.uio_resid = cnt;
 	uio.uio_segflg = UIO_USERSPACE;
 	uio.uio_td = td;
 	flags = MSG_NBIO;
 
 	/*
 	 * For resource usage accounting, only count a completed request
 	 * as a single message to avoid counting multiple calls to
 	 * sosend/soreceive on a blocking socket.
 	 */
 
 	if (sb == &so->so_rcv) {
 		uio.uio_rw = UIO_READ;
 		ru_before = td->td_ru.ru_msgrcv;
 #ifdef MAC
 		error = mac_socket_check_receive(fp->f_cred, so);
 		if (error == 0)
 
 #endif
 			error = soreceive(so, NULL, &uio, NULL, NULL, &flags);
 		if (td->td_ru.ru_msgrcv != ru_before)
 			job->msgrcv = 1;
 	} else {
 		if (!TAILQ_EMPTY(&sb->sb_aiojobq))
 			flags |= MSG_MORETOCOME;
 		uio.uio_rw = UIO_WRITE;
 		ru_before = td->td_ru.ru_msgsnd;
 #ifdef MAC
 		error = mac_socket_check_send(fp->f_cred, so);
 		if (error == 0)
 #endif
 			error = sosend(so, NULL, &uio, NULL, NULL, flags, td);
 		if (td->td_ru.ru_msgsnd != ru_before)
 			job->msgsnd = 1;
 		if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
 			PROC_LOCK(job->userproc);
 			kern_psignal(job->userproc, SIGPIPE);
 			PROC_UNLOCK(job->userproc);
 		}
 	}
 
 	done += cnt - uio.uio_resid;
 	job->aio_done = done;
 	td->td_ucred = td_savedcred;
 
 	if (error == EWOULDBLOCK) {
 		/*
 		 * The request was either partially completed or not
 		 * completed at all due to racing with a read() or
 		 * write() on the socket.  If the socket is
 		 * non-blocking, return with any partial completion.
 		 * If the socket is blocking or if no progress has
 		 * been made, requeue this request at the head of the
 		 * queue to try again when the socket is ready.
 		 */
 		MPASS(done != job->uaiocb.aio_nbytes);
 		SOCKBUF_LOCK(sb);
 		if (done == 0 || !(so->so_state & SS_NBIO)) {
 			empty_results++;
 			if (soaio_ready(so, sb)) {
 				empty_retries++;
 				SOCKBUF_UNLOCK(sb);
 				goto retry;
 			}
 			
 			if (!aio_set_cancel_function(job, soo_aio_cancel)) {
 				SOCKBUF_UNLOCK(sb);
 				if (done != 0)
 					aio_complete(job, done, 0);
 				else
 					aio_cancel(job);
 				SOCKBUF_LOCK(sb);
 			} else {
 				TAILQ_INSERT_HEAD(&sb->sb_aiojobq, job, list);
 			}
 			return;
 		}
 		SOCKBUF_UNLOCK(sb);
 	}		
 	if (done != 0 && (error == ERESTART || error == EINTR ||
 	    error == EWOULDBLOCK))
 		error = 0;
 	if (error)
 		aio_complete(job, -1, error);
 	else
 		aio_complete(job, done, 0);
 	SOCKBUF_LOCK(sb);
 }
 
 static void
 soaio_process_sb(struct socket *so, struct sockbuf *sb)
 {
 	struct kaiocb *job;
 
 	CURVNET_SET(so->so_vnet);
 	SOCKBUF_LOCK(sb);
 	while (!TAILQ_EMPTY(&sb->sb_aiojobq) && soaio_ready(so, sb)) {
 		job = TAILQ_FIRST(&sb->sb_aiojobq);
 		TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
 		if (!aio_clear_cancel_function(job))
 			continue;
 
 		soaio_process_job(so, sb, job);
 	}
 
 	/*
 	 * If there are still pending requests, the socket must not be
 	 * ready so set SB_AIO to request a wakeup when the socket
 	 * becomes ready.
 	 */
 	if (!TAILQ_EMPTY(&sb->sb_aiojobq))
 		sb->sb_flags |= SB_AIO;
 	sb->sb_flags &= ~SB_AIO_RUNNING;
 	SOCKBUF_UNLOCK(sb);
 
 	SOCK_LOCK(so);
 	sorele(so);
 	CURVNET_RESTORE();
 }
 
 void
 soaio_rcv(void *context, int pending)
 {
 	struct socket *so;
 
 	so = context;
 	soaio_process_sb(so, &so->so_rcv);
 }
 
 void
 soaio_snd(void *context, int pending)
 {
 	struct socket *so;
 
 	so = context;
 	soaio_process_sb(so, &so->so_snd);
 }
 
 void
 sowakeup_aio(struct socket *so, struct sockbuf *sb)
 {
 
 	SOCKBUF_LOCK_ASSERT(sb);
 	sb->sb_flags &= ~SB_AIO;
 	if (sb->sb_flags & SB_AIO_RUNNING)
 		return;
 	sb->sb_flags |= SB_AIO_RUNNING;
 	soref(so);
 	soaio_enqueue(&sb->sb_aiotask);
 }
 
 static void
 soo_aio_cancel(struct kaiocb *job)
 {
 	struct socket *so;
 	struct sockbuf *sb;
 	long done;
 	int opcode;
 
 	so = job->fd_file->f_data;
 	opcode = job->uaiocb.aio_lio_opcode;
 	if (opcode == LIO_READ)
 		sb = &so->so_rcv;
 	else {
 		MPASS(opcode == LIO_WRITE);
 		sb = &so->so_snd;
 	}
 
 	SOCKBUF_LOCK(sb);
 	if (!aio_cancel_cleared(job))
 		TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
 	if (TAILQ_EMPTY(&sb->sb_aiojobq))
 		sb->sb_flags &= ~SB_AIO;
 	SOCKBUF_UNLOCK(sb);
 
 	done = job->aio_done;
 	if (done != 0)
 		aio_complete(job, done, 0);
 	else
 		aio_cancel(job);
 }
 
 static int
 soo_aio_queue(struct file *fp, struct kaiocb *job)
 {
 	struct socket *so;
 	struct sockbuf *sb;
 	int error;
 
 	so = fp->f_data;
 	error = (*so->so_proto->pr_usrreqs->pru_aio_queue)(so, job);
 	if (error == 0)
 		return (0);
 
 	switch (job->uaiocb.aio_lio_opcode) {
 	case LIO_READ:
 		sb = &so->so_rcv;
 		break;
 	case LIO_WRITE:
 		sb = &so->so_snd;
 		break;
 	default:
 		return (EINVAL);
 	}
 
 	SOCKBUF_LOCK(sb);
 	if (!aio_set_cancel_function(job, soo_aio_cancel))
 		panic("new job was cancelled");
 	TAILQ_INSERT_TAIL(&sb->sb_aiojobq, job, list);
 	if (!(sb->sb_flags & SB_AIO_RUNNING)) {
 		if (soaio_ready(so, sb))
 			sowakeup_aio(so, sb);
 		else
 			sb->sb_flags |= SB_AIO;
 	}
 	SOCKBUF_UNLOCK(sb);
 	return (0);
 }