Re: [PATCH] add semtimedop call to kernel 2.5.46 (was against 2.4.19)

From: Mark Fasheh (mfasheh@linux.ucla.edu)
Date: Tue Nov 05 2002 - 01:45:47 EST


Alan, thank you very much for the feedback. I fixed the dumb variable naming
and have ported the patch to kernel 2.5.46 (inlined below). As always, I'd
love feedback, otherwise it'd be cool to see this merged :)

On Mon, Nov 04, 2002 at 08:02:51PM +0000, Alan Cox wrote:
> On Mon, 2002-11-04 at 19:26, Mark Fasheh wrote:
> > Hello,
> > Included is a patch against 2.4.19 to allow semaphore operations
> > with timeouts. The new call functions exactly like semtimedop in Solaris.
> > Userspace code to use/test this new syscall can be found at:
> > http://www.exothermic.org/linux/semtimedop.tar.gz
> > Feedback is greatly appreciated :)
>
> Only two feedbacks from a first glance - its a 2.5 type change not a 2.4
> one. Also call your local variable something other than "jiffies" as
> that is used for a global to do with time !

diff -urNp linux-2.5.46-orig/arch/i386/kernel/sys_i386.c linux-2.5.46/arch/i386/kernel/sys_i386.c
--- linux-2.5.46-orig/arch/i386/kernel/sys_i386.c 2002-11-04 14:30:52.000000000 -0800
+++ linux-2.5.46/arch/i386/kernel/sys_i386.c 2002-11-04 21:06:25.000000000 -0800
@@ -140,7 +140,11 @@ asmlinkage int sys_ipc (uint call, int f
 
         switch (call) {
         case SEMOP:
- return sys_semop (first, (struct sembuf *)ptr, second);
+ return sys_semtimedop (first, (struct sembuf *)ptr, second, NULL);
+ case SEMTIMEDOP:
+ return sys_semtimedop (first, (struct sembuf *)ptr, second,
+ (const struct timespec *)fifth);
+
         case SEMGET:
                 return sys_semget (first, second, third);
         case SEMCTL: {
diff -urNp linux-2.5.46-orig/arch/ia64/ia32/sys_ia32.c linux-2.5.46/arch/ia64/ia32/sys_ia32.c
--- linux-2.5.46-orig/arch/ia64/ia32/sys_ia32.c 2002-11-04 14:30:33.000000000 -0800
+++ linux-2.5.46/arch/ia64/ia32/sys_ia32.c 2002-11-04 21:08:30.000000000 -0800
@@ -2124,6 +2124,7 @@ struct ipc_kludge {
 #define SEMOP 1
 #define SEMGET 2
 #define SEMCTL 3
+#define SEMTIMEDOP 4
 #define MSGSND 11
 #define MSGRCV 12
 #define MSGGET 13
diff -urNp linux-2.5.46-orig/arch/ia64/kernel/entry.S linux-2.5.46/arch/ia64/kernel/entry.S
--- linux-2.5.46-orig/arch/ia64/kernel/entry.S 2002-11-04 14:30:15.000000000 -0800
+++ linux-2.5.46/arch/ia64/kernel/entry.S 2002-11-04 21:11:39.000000000 -0800
@@ -1254,7 +1254,7 @@ sys_call_table:
         data8 sys_epoll_create
         data8 sys_epoll_ctl
         data8 sys_epoll_wait // 1245
- data8 ia64_ni_syscall
+ data8 sys_semtimedop
         data8 ia64_ni_syscall
         data8 ia64_ni_syscall
         data8 ia64_ni_syscall
diff -urNp linux-2.5.46-orig/include/asm-i386/ipc.h linux-2.5.46/include/asm-i386/ipc.h
--- linux-2.5.46-orig/include/asm-i386/ipc.h 2002-11-04 14:30:49.000000000 -0800
+++ linux-2.5.46/include/asm-i386/ipc.h 2002-11-04 21:44:53.000000000 -0800
@@ -14,6 +14,7 @@ struct ipc_kludge {
 #define SEMOP 1
 #define SEMGET 2
 #define SEMCTL 3
+#define SEMTIMEDOP 4
 #define MSGSND 11
 #define MSGRCV 12
 #define MSGGET 13
diff -urNp linux-2.5.46-orig/include/asm-ia64/unistd.h linux-2.5.46/include/asm-ia64/unistd.h
--- linux-2.5.46-orig/include/asm-ia64/unistd.h 2002-11-04 14:30:07.000000000 -0800
+++ linux-2.5.46/include/asm-ia64/unistd.h 2002-11-04 21:13:19.000000000 -0800
@@ -235,6 +235,7 @@
 #define __NR_epoll_create 1243
 #define __NR_epoll_ctl 1244
 #define __NR_epoll_wait 1245
+#define __NR_semtimedop 1246
 
 #if !defined(__ASSEMBLY__) && !defined(ASSEMBLER)
 
diff -urNp linux-2.5.46-orig/include/linux/sem.h linux-2.5.46/include/linux/sem.h
--- linux-2.5.46-orig/include/linux/sem.h 2002-11-04 14:30:24.000000000 -0800
+++ linux-2.5.46/include/linux/sem.h 2002-11-04 21:15:39.000000000 -0800
@@ -140,6 +140,8 @@ struct sysv_sem {
 asmlinkage long sys_semget (key_t key, int nsems, int semflg);
 asmlinkage long sys_semop (int semid, struct sembuf *sops, unsigned nsops);
 asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg);
+asmlinkage long sys_semtimedop (int semid, struct sembuf *sops,
+ unsigned nsops, const struct timespec *timeout);
 
 #endif /* __KERNEL__ */
 
diff -urNp linux-2.5.46-orig/ipc/sem.c linux-2.5.46/ipc/sem.c
--- linux-2.5.46-orig/ipc/sem.c 2002-11-04 14:30:22.000000000 -0800
+++ linux-2.5.46/ipc/sem.c 2002-11-04 21:19:02.000000000 -0800
@@ -62,6 +62,7 @@
 #include <linux/spinlock.h>
 #include <linux/init.h>
 #include <linux/proc_fs.h>
+#include <linux/time.h>
 #include <linux/smp_lock.h>
 #include <linux/security.h>
 #include <asm/uaccess.h>
@@ -969,6 +970,12 @@ static int alloc_undo(struct sem_array *
 
 asmlinkage long sys_semop (int semid, struct sembuf *tsops, unsigned nsops)
 {
+ return sys_semtimedop(semid, tsops, nsops, NULL);
+}
+
+asmlinkage long sys_semtimedop (int semid, struct sembuf *tsops,
+ unsigned nsops, const struct timespec *timeout)
+{
         int error = -EINVAL;
         struct sem_array *sma;
         struct sembuf fast_sops[SEMOPM_FAST];
@@ -976,6 +983,7 @@ asmlinkage long sys_semop (int semid, st
         struct sem_undo *un;
         int undos = 0, decrease = 0, alter = 0;
         struct sem_queue queue;
+ unsigned long offset = MAX_SCHEDULE_TIMEOUT;
 
 
         if (nsops < 1 || semid < 0)
@@ -991,6 +999,19 @@ asmlinkage long sys_semop (int semid, st
                 error=-EFAULT;
                 goto out_free;
         }
+ if (timeout) {
+ struct timespec _timeout;
+ if (copy_from_user(&_timeout, timeout, sizeof(*timeout))) {
+ error = -EFAULT;
+ goto out_free;
+ }
+ if (_timeout.tv_sec < 0 || _timeout.tv_nsec < 0 ||
+ _timeout.tv_nsec >= 1000000000L) {
+ error = -EINVAL;
+ goto out_free;
+ }
+ offset = timespec_to_jiffies(&_timeout);
+ }
         lock_semundo();
         sma = sem_lock(semid);
         error=-EINVAL;
@@ -1058,7 +1079,7 @@ asmlinkage long sys_semop (int semid, st
                 sem_unlock(sma);
                 unlock_semundo();
 
- schedule();
+ offset = schedule_timeout(offset);
 
                 lock_semundo();
                 sma = sem_lock(semid);
@@ -1084,6 +1105,8 @@ asmlinkage long sys_semop (int semid, st
                                 break;
                 } else {
                         error = queue.status;
+ if (error == -EINTR && offset == 0)
+ error = -EAGAIN;
                         if (queue.prev) /* got Interrupt */
                                 break;
                         /* Everything done by update_queue */
diff -urNp linux-2.5.46-orig/ipc/util.c linux-2.5.46/ipc/util.c
--- linux-2.5.46-orig/ipc/util.c 2002-11-04 14:30:24.000000000 -0800
+++ linux-2.5.46/ipc/util.c 2002-11-04 21:16:39.000000000 -0800
@@ -532,6 +532,13 @@ asmlinkage long sys_semop (int semid, st
         return -ENOSYS;
 }
 
+asmlinkage long sys_semtimedop (int semid, struct sembuf *sops, unsigned nsops,
+ const struct timespec *timeout)
+{
+ return -ENOSYS;
+}
+
+
 asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
 {
         return -ENOSYS;
-
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