* sysv_sem.cc: Update to FreeBSD version 1.69.

	1.68: Reduce the overhead of semop() by using the kernel stack
	instead of malloc'd memory to store the operations array if it
	is small enough to fit.
	1.69: Adjust the number of processes waiting on a semaphore properly
	if we're woken up in the middle of sleeping.

diff --git a/winsup/cygserver/ChangeLog b/winsup/cygserver/ChangeLog
index 99b69a2..5597350 100644 (file)
--- a/winsup/cygserver/ChangeLog
+++ b/winsup/cygserver/ChangeLog
@@ -1,3 +1,12 @@
+2004-10-01  Corinna Vinschen  <corinna@vinschen.de>
+
+       * sysv_sem.cc: Update to FreeBSD version 1.69.
+       1.68: Reduce the overhead of semop() by using the kernel stack
+       instead of malloc'd memory to store the operations array if it
+       is small enough to fit.
+       1.69: Adjust the number of processes waiting on a semaphore properly
+       if we're woken up in the middle of sleeping.
+
 2004-09-23  Corinna Vinschen  <corinna@vinschen.de>
 
        * sysv_shm.cc (kern_shmat): Avoid compiler warning.

diff --git a/winsup/cygserver/sysv_sem.cc b/winsup/cygserver/sysv_sem.cc
index bcb312d..a4acf37 100644 (file)
--- a/winsup/cygserver/sysv_sem.cc
+++ b/winsup/cygserver/sysv_sem.cc
@@ -17,7 +17,7 @@
 #ifndef __FBSDID
 #define __FBSDID(s)    const char version[] = (s)
 #endif
-__FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/kern/sysv_sem.c,v 1.67 2003/11/15 11:56:53 tjr Exp $");
+__FBSDID("$FreeBSD: /repoman/r/ncvs/src/sys/kern/sysv_sem.c,v 1.70 2004/05/30 20:34:58 phk Exp $");
 
 #define _KERNEL 1
 #define __BSD_VISIBLE 1
@@ -953,6 +953,8 @@ struct semop_args {
 int
 semop(struct thread *td, struct semop_args *uap)
 {
+#define SMALL_SOPS      8
+       struct sembuf small_sops[SMALL_SOPS];
        int semid = uap->semid;
        size_t nsops = uap->nsops;
        struct sembuf *sops;
@@ -976,16 +978,20 @@ semop(struct thread *td, struct semop_args *uap)
                return (EINVAL);
 
        /* Allocate memory for sem_ops */
-       if (nsops > (unsigned long) seminfo.semopm) {
+       if (nsops <= SMALL_SOPS)
+               sops = small_sops;
+       else if (nsops <= (unsigned long) seminfo.semopm)
+               sops = (struct sembuf *) sys_malloc(nsops * sizeof(*sops), M_SEM, M_WAITOK);
+       else {
                DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
                    nsops));
                return (E2BIG);
        }
-       sops = (struct sembuf *) sys_malloc(nsops * sizeof(sops[0]), M_SEM, M_WAITOK);
        if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) {
                DPRINTF(("error = %d from copyin(%08x, %08x, %d)\n", error,
                    uap->sops, sops, nsops * sizeof(sops[0])));
-               sys_free(sops, M_SEM);
+               if (sops != small_sops)
+                       sys_free(sops, M_SEM);
                return (error);
        }
 
@@ -1110,15 +1116,7 @@ semop(struct thread *td, struct semop_args *uap)
                error = msleep(semaptr, sema_mtxp, (PZERO - 4) | PCATCH,
                    "semwait", 0);
                DPRINTF(("semop:  good morning (error=%d)!\n", error));
-
-               if (error != 0) {
-#ifdef __CYGWIN__
-                   if (error != EIDRM)
-#endif /* __CYGWIN__ */
-                       error = EINTR;
-                       goto done2;
-               }
-               DPRINTF(("semop:  good morning!\n"));
+               /* return code is checked below, after sem[nz]cnt-- */
 
                /*
                 * Make sure that the semaphore still exists
@@ -1137,6 +1135,20 @@ semop(struct thread *td, struct semop_args *uap)
                        semptr->semzcnt--;
                else
                        semptr->semncnt--;
+
+               /*
+                * Is it really morning, or was our sleep interrupted?
+                * (Delayed check of msleep() return code because we
+                * need to decrement sem[nz]cnt either way.)
+                */
+               if (error != 0) {
+#ifdef __CYGWIN__
+                   if (error != EIDRM)
+#endif /* __CYGWIN__ */
+                       error = EINTR;
+                       goto done2;
+               }
+               DPRINTF(("semop:  good morning!\n"));
        }
 
 done:
@@ -1216,7 +1228,8 @@ done:
        td->td_retval[0] = 0;
 done2:
        mtx_unlock(sema_mtxp);
-       sys_free(sops, M_SEM);
+       if (sops != small_sops)
+               sys_free(sops, M_SEM);
        return (error);
 }