- Retry the operations (instead of failing) in case of reallocation.

Suggested by <yamt>.
- Use predicts in checks for reallocation state.

sys/kern/sysv_msg.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: sysv_msg.c,v 1.52 2007/11/04 13:09:32 yamt Exp $	*/
+/*	$NetBSD: sysv_msg.c,v 1.53 2007/11/25 19:03:24 rmind Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2006, 2007 The NetBSD Foundation, Inc.
@@ -57,7 +57,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sysv_msg.c,v 1.52 2007/11/04 13:09:32 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sysv_msg.c,v 1.53 2007/11/25 19:03:24 rmind Exp $");
 
 #define SYSVMSG
 
@@ -659,15 +659,13 @@ msgsnd1(struct lwp *l, int msqidr, const char *user_msgp, size_t msgsz,
 
 	MSG_PRINTF(("call to msgsnd(%d, %p, %lld, %d)\n", msqid, user_msgp,
 	    (long long)msgsz, msgflg));
-
+restart:
 	msqid = IPCID_TO_IX(msqidr);
 
 	mutex_enter(&msgmutex);
-	if (msg_realloc_state) {
+	/* In case of reallocation, we will wait for completion */
-		/* In case of reallocation, we will wait for completion */
+	while (__predict_false(msg_realloc_state))
-		while (msg_realloc_state)
+		cv_wait(&msg_realloc_cv, &msgmutex);
-			cv_wait(&msg_realloc_cv, &msgmutex);
-	}
 
 	if (msqid < 0 || msqid >= msginfo.msgmni) {
 		MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
@@ -756,13 +754,20 @@ msgsnd1(struct lwp *l, int msqidr, const char *user_msgp, size_t msgsz,
 			MSG_PRINTF(("good morning, error=%d\n", error));
 			msg_waiters--;
 
-			/* Notify reallocator, in case of such state */
-			if (msg_realloc_state)
-				cv_broadcast(&msg_realloc_cv);
-
 			if (we_own_it)
 				msqptr->msg_perm.mode &= ~MSG_LOCKED;
-			if (error || msg_realloc_state) {
+
+			/*
+			 * In case of such state, notify reallocator and
+			 * restart the call.
+			 */
+			if (msg_realloc_state) {
+				cv_broadcast(&msg_realloc_cv);
+				mutex_exit(&msgmutex);
+				goto restart;
+			}
+
+			if (error != 0) {
 				MSG_PRINTF(("msgsnd: interrupted system "
 				    "call\n"));
 				error = EINTR;
@@ -959,15 +964,13 @@ msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp,
 
 	MSG_PRINTF(("call to msgrcv(%d, %p, %lld, %ld, %d)\n", msqid,
 	    user_msgp, (long long)msgsz, msgtyp, msgflg));
-
+restart:
 	msqid = IPCID_TO_IX(msqidr);
 
 	mutex_enter(&msgmutex);
-	if (msg_realloc_state) {
+	/* In case of reallocation, we will wait for completion */
-		/* In case of reallocation, we will wait for completion */
+	while (__predict_false(msg_realloc_state))
-		while (msg_realloc_state)
+		cv_wait(&msg_realloc_cv, &msgmutex);
-			cv_wait(&msg_realloc_cv, &msgmutex);
-	}
 
 	if (msqid < 0 || msqid >= msginfo.msgmni) {
 		MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
@@ -1090,11 +1093,17 @@ msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp,
 		MSG_PRINTF(("msgrcv: good morning (error=%d)\n", error));
 		msg_waiters--;
 
-		/* Notify reallocator, in case of such state */
+		/*
-		if (msg_realloc_state)
+		 * In case of such state, notify reallocator and
+		 * restart the call.
+		 */
+		if (msg_realloc_state) {
 			cv_broadcast(&msg_realloc_cv);
+			mutex_exit(&msgmutex);
+			goto restart;
+		}
 
-		if (error || msg_realloc_state) {
+		if (error != 0) {
 			MSG_PRINTF(("msgsnd: interrupted system call\n"));
 			error = EINTR;
 			goto unlock;

sys/kern/sysv_sem.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: sysv_sem.c,v 1.75 2007/11/04 13:09:33 yamt Exp $	*/
+/*	$NetBSD: sysv_sem.c,v 1.76 2007/11/25 19:03:24 rmind Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2007 The NetBSD Foundation, Inc.
@@ -46,7 +46,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sysv_sem.c,v 1.75 2007/11/04 13:09:33 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sysv_sem.c,v 1.76 2007/11/25 19:03:24 rmind Exp $");
 
 #define SYSVSEM
 
@@ -760,7 +760,7 @@ sys_semop(struct lwp *l, void *v, register_t *retval)
 	int do_wakeup, do_undos;
 
 	SEM_PRINTF(("call to semop(%d, %p, %zd)\n", semid, SCARG(uap,sops), nsops));
-
+restart:
 	if (nsops <= SMALL_SOPS) {
 		sops = small_sops;
 	} else if (nsops <= seminfo.semopm) {
@@ -774,11 +774,9 @@ sys_semop(struct lwp *l, void *v, register_t *retval)
 	}
 
 	mutex_enter(&semlock);
-	if (sem_realloc_state) {
+	/* In case of reallocation, we will wait for completion */
-		/* In case of reallocation, we will wait for completion */
+	while (__predict_false(sem_realloc_state))
-		while (sem_realloc_state)
+		cv_wait(&sem_realloc_cv, &semlock);
-			cv_wait(&sem_realloc_cv, &semlock);
-	}
 
 	semid = IPCID_TO_IX(semid);	/* Convert back to zero origin */
 	if (semid < 0 || semid >= seminfo.semmni) {
@@ -899,9 +897,8 @@ sys_semop(struct lwp *l, void *v, register_t *retval)
 		SEM_PRINTF(("semop:  good morning (error=%d)!\n", error));
 		sem_waiters--;
 
-		/* Notify reallocator, in case of such state */
+		/* Notify reallocator, if it is waiting */
-		if (sem_realloc_state)
+		cv_broadcast(&sem_realloc_cv);
-			cv_broadcast(&sem_realloc_cv);
 
 		/*
 		 * Make sure that the semaphore still exists
@@ -922,8 +919,14 @@ sys_semop(struct lwp *l, void *v, register_t *retval)
 		else
 			semptr->semncnt--;
 
+		/* In case of such state, restart the call */
+		if (sem_realloc_state) {
+			mutex_exit(&semlock);
+			goto restart;
+		}
+
 		/* Is it really morning, or was our sleep interrupted? */
-		if (error || sem_realloc_state) {
+		if (error != 0) {
 			error = EINTR;
 			goto out;
 		}