The bug is fixed in my latest version of the SMP-threaded ipc/sem code.
The code seems stable, please test it.
--
Manfred
<<<<<<<<<<<<<<<<<<<
// $Header: /pub/cvs/ms/patches/patch-ipcsem,v 1.5 1999/10/22 22:25:03 manfreds Exp $
// Kernel Version:
// VERSION = 2
// PATCHLEVEL = 3
// SUBLEVEL = 23
// EXTRAVERSION =
diff -r -u 2.3/include/linux/ipc.h build-2.3/include/linux/ipc.h
--- 2.3/include/linux/ipc.h Mon Dec 28 07:18:28 1998
+++ build-2.3/include/linux/ipc.h Fri Oct 22 22:18:44 1999
@@ -38,7 +38,7 @@
#ifdef __KERNEL__
-/* special shmsegs[id], msgque[id] or semary[id] values */
+/* special shmsegs[id] values */
#define IPC_UNUSED ((void *) -1)
#define IPC_NOID ((void *) -2) /* being allocated/destroyed */
diff -r -u 2.3/include/linux/sem.h build-2.3/include/linux/sem.h
--- 2.3/include/linux/sem.h Thu Aug 26 17:59:51 1999
+++ build-2.3/include/linux/sem.h Fri Oct 22 22:18:47 1999
@@ -81,15 +81,16 @@
int sempid; /* pid of last operation */
};
-/* One queue for each semaphore set in the system. */
+/* One queue for each sleeping process in the system. */
struct sem_queue {
struct sem_queue * next; /* next entry in the queue */
struct sem_queue ** prev; /* previous entry in the queue, *(q->prev) == q */
- wait_queue_head_t sleeper; /* sleeping process */
+ struct task_struct* sleeper; /* this process */
struct sem_undo * undo; /* undo structure */
int pid; /* process id of requesting process */
int status; /* completion status of operation */
struct semid_ds * sma; /* semaphore array for operations */
+ int id; /* internal sem id */
struct sembuf * sops; /* array of pending operations */
int nsops; /* number of operations */
int alter; /* operation will alter semaphore */
diff -r -u 2.3/ipc/sem.c build-2.3/ipc/sem.c
--- 2.3/ipc/sem.c Thu Aug 26 17:59:52 1999
+++ build-2.3/ipc/sem.c Fri Oct 22 23:53:38 1999
@@ -50,11 +50,13 @@
* array we do the same as before.
*
* /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
+ *
+ * SMP-threaded (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
*/
#include <linux/config.h>
#include <linux/malloc.h>
-#include <linux/smp_lock.h>
+#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
@@ -68,13 +70,31 @@
static int sysvipc_sem_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif
-static struct semid_ds *semary[SEMMNI];
-static int used_sems = 0, used_semids = 0;
-static DECLARE_WAIT_QUEUE_HEAD(sem_lock);
+struct semid_ary
+{
+ spinlock_t lock;
+ struct semid_ds* s;
+};
+
+static struct semid_ary semary[SEMMNI];
+
+static DECLARE_MUTEX(sem_lock);
static int max_semid = 0;
+static int used_sems = 0;
+static int used_semids = 0;
static unsigned short sem_seq = 0;
+/* anti-deadlock ordering:
+ * sem_lock < semary[].lock
+ * linked list protection:
+ * sem_undo.id_next,
+ * semid_ds.sem_pending{,last},
+ * semid_ds.sem_undo: semary[].lock for read/write
+ * sem_undo.proc_next: only "current" is allowed to read/write that field.
+ *
+ */
+
void __init sem_init (void)
{
int i;
@@ -82,10 +102,11 @@
struct proc_dir_entry *ent;
#endif
- init_waitqueue_head(&sem_lock);
used_sems = used_semids = max_semid = sem_seq = 0;
- for (i = 0; i < SEMMNI; i++)
- semary[i] = (struct semid_ds *) IPC_UNUSED;
+ for (i = 0; i < SEMMNI; i++) {
+ semary[i].lock = SPIN_LOCK_UNLOCKED;
+ semary[i].s = NULL;
+ }
#ifdef CONFIG_PROC_FS
ent = create_proc_entry("sysvipc/sem", 0, 0);
ent->read_proc = sysvipc_sem_read_proc;
@@ -99,10 +120,10 @@
struct semid_ds *sma;
for (id = 0; id <= max_semid; id++) {
- while ((sma = semary[id]) == IPC_NOID)
- interruptible_sleep_on (&sem_lock);
- if (sma == IPC_UNUSED)
+ sma = semary[id].s;
+ if(sma==NULL)
continue;
+
if (key == sma->sem_perm.key)
return id;
}
@@ -120,20 +141,17 @@
return -EINVAL;
if (used_sems + nsems > SEMMNS)
return -ENOSPC;
- for (id = 0; id < SEMMNI; id++)
- if (semary[id] == IPC_UNUSED) {
- semary[id] = (struct semid_ds *) IPC_NOID;
+ for (id = 0; id < SEMMNI; id++) {
+ if(semary[id].s == NULL)
goto found;
- }
+ }
return -ENOSPC;
found:
size = sizeof (*sma) + nsems * sizeof (struct sem);
used_sems += nsems;
sma = (struct semid_ds *) kmalloc (size, GFP_KERNEL);
if (!sma) {
- semary[id] = (struct semid_ds *) IPC_UNUSED;
used_sems -= nsems;
- wake_up (&sem_lock);
return -ENOMEM;
}
memset (sma, 0, size);
@@ -143,7 +161,10 @@
ipcp->key = key;
ipcp->cuid = ipcp->uid = current->euid;
ipcp->gid = ipcp->cgid = current->egid;
- sma->sem_perm.seq = sem_seq;
+ /* sma->sem_perm.seq*MSGMNI must be a positive integer.
+ * this limits MSGMNI to 32768
+ */
+ sma->sem_perm.seq = sem_seq++;
/* sma->sem_pending = NULL; */
sma->sem_pending_last = &sma->sem_pending;
/* sma->undo = NULL; */
@@ -152,8 +173,9 @@
if (id > max_semid)
max_semid = id;
used_semids++;
- semary[id] = sma;
- wake_up (&sem_lock);
+ spin_lock(&semary[id].lock);
+ semary[id].s = sma;
+ spin_unlock(&semary[id].lock);
return (unsigned int) sma->sem_perm.seq * SEMMNI + id;
}
@@ -162,9 +184,10 @@
int id, err = -EINVAL;
struct semid_ds *sma;
- lock_kernel();
if (nsems < 0 || nsems > SEMMSL)
- goto out;
+ return -EINVAL;
+ down(&sem_lock);
+
if (key == IPC_PRIVATE) {
err = newary(key, nsems, semflg);
} else if ((id = findkey (key)) == -1) { /* key not used */
@@ -175,7 +198,7 @@
} else if (semflg & IPC_CREAT && semflg & IPC_EXCL) {
err = -EEXIST;
} else {
- sma = semary[id];
+ sma = semary[id].s;
if (nsems > sma->sem_nsems)
err = -EINVAL;
else if (ipcperms(&sma->sem_perm, semflg))
@@ -183,8 +206,8 @@
else
err = (int) sma->sem_perm.seq * SEMMNI + id;
}
-out:
- unlock_kernel();
+
+ up(&sem_lock);
return err;
}
@@ -304,7 +327,7 @@
/* Does q->sleeper still need to sleep? */
if (error <= 0) {
/* Found one, wake it up */
- wake_up_interruptible(&q->sleeper);
+ wake_up_process(q->sleeper);
if (error == 0 && q->alter) {
/* if q-> alter let it self try */
q->status = 1;
@@ -365,21 +388,22 @@
/* Free a semaphore set. */
static void freeary (int id)
{
- struct semid_ds *sma = semary[id];
+ struct semid_ds *sma;
struct sem_undo *un;
struct sem_queue *q;
- /* Invalidate this semaphore set */
- sma->sem_perm.seq++;
- sem_seq = (sem_seq+1) % ((unsigned)(1<<31)/SEMMNI); /* increment, but avoid overflow */
+ /* we own both locks, noone can get in */
+ sma = semary[id].s;
+ semary[id].s = NULL;
+
used_sems -= sma->sem_nsems;
if (id == max_semid)
- while (max_semid && (semary[--max_semid] == IPC_UNUSED));
- semary[id] = (struct semid_ds *) IPC_UNUSED;
+ while (max_semid && (semary[--max_semid].s == NULL));
used_semids--;
/* Invalidate the existing undo structures for this semaphore set.
- * (They will be freed without any further action in sem_exit().)
+ * (They will be freed without any further action in sem_exit()
+ * or during the next semop.)
*/
for (un = sma->undo; un; un = un->id_next)
un->semid = -1;
@@ -388,35 +412,23 @@
for (q = sma->sem_pending; q; q = q->next) {
q->status = -EIDRM;
q->prev = NULL;
- wake_up_interruptible(&q->sleeper); /* doesn't sleep! */
+ wake_up_process(q->sleeper); /* doesn't sleep */
}
kfree(sma);
}
-asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
+int semctl_nolock(int semid, int semnum, int cmd, union semun arg)
{
- struct semid_ds *buf = NULL;
- struct semid_ds tbuf;
- int i, id, val = 0;
- struct semid_ds *sma;
- struct ipc_perm *ipcp;
- struct sem *curr = NULL;
- struct sem_undo *un;
- unsigned int nsems;
- ushort *array = NULL;
- ushort sem_io[SEMMSL];
int err = -EINVAL;
+ int lid = semid % SEMMNI;
- lock_kernel();
- if (semid < 0 || semnum < 0 || cmd < 0)
- goto out;
-
- switch (cmd) {
+ switch(cmd) {
case IPC_INFO:
case SEM_INFO:
{
- struct seminfo seminfo, *tmp = arg.__buf;
+ struct seminfo seminfo;
+
seminfo.semmni = SEMMNI;
seminfo.semmns = SEMMNS;
seminfo.semmsl = SEMMSL;
@@ -428,174 +440,201 @@
seminfo.semusz = SEMUSZ;
seminfo.semaem = SEMAEM;
if (cmd == SEM_INFO) {
+ down(&sem_lock);
seminfo.semusz = used_semids;
seminfo.semaem = used_sems;
+ up(&sem_lock);
}
- err = -EFAULT;
- if (copy_to_user (tmp, &seminfo, sizeof(struct seminfo)))
- goto out;
- err = max_semid;
- goto out;
+ if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo)))
+ return -EFAULT;
+ return max_semid;
}
-
case SEM_STAT:
- buf = arg.buf;
- err = -EINVAL;
+ {
+ struct semid_ds *sma;
+ struct semid_ds tbuf;
+ int id;
+
if (semid > max_semid)
- goto out;
- sma = semary[semid];
- if (sma == IPC_UNUSED || sma == IPC_NOID)
- goto out;
+ return -EINVAL;
+
+ spin_lock(&semary[lid].lock);
+ err = -EINVAL;
+ sma = semary[semid].s;
+ if (sma == NULL)
+ goto out_unlock;
err = -EACCES;
if (ipcperms (&sma->sem_perm, S_IRUGO))
- goto out;
+ goto out_unlock;
id = (unsigned int) sma->sem_perm.seq * SEMMNI + semid;
+ memset(&tbuf,0,sizeof(tbuf));
tbuf.sem_perm = sma->sem_perm;
tbuf.sem_otime = sma->sem_otime;
tbuf.sem_ctime = sma->sem_ctime;
tbuf.sem_nsems = sma->sem_nsems;
- err = -EFAULT;
- if (copy_to_user (buf, &tbuf, sizeof(*buf)) == 0)
- err = id;
- goto out;
+ spin_unlock(&semary[lid].lock);
+ if (copy_to_user (arg.buf, &tbuf, sizeof(tbuf)))
+ return -EFAULT;
+ return id;
+ }
+ default:
+ return -EINVAL;
}
+ return err;
+out_unlock:
+ spin_unlock(&semary[lid].lock);
+ return err;
+}
- id = (unsigned int) semid % SEMMNI;
- sma = semary [id];
- err = -EINVAL;
- if (sma == IPC_UNUSED || sma == IPC_NOID)
- goto out;
- ipcp = &sma->sem_perm;
- nsems = sma->sem_nsems;
- err = -EIDRM;
+int semctl_locked_unlock(int semid, int semnum, int cmd, union semun arg)
+{
+ struct semid_ds *sma;
+ struct semid_ds tbuf;
+ int err;
+ int lid = semid % SEMMNI;
+
+ sma = semary[lid].s;
+ err=-EINVAL;
+ if (sma == NULL)
+ goto out_unlock;
+ err=-EIDRM;
if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI)
- goto out;
+ goto out_unlock;
+ err = -EACCES;
+ if (ipcperms(&sma->sem_perm, S_IRUGO))
+ goto out_unlock;
+
switch (cmd) {
- case GETVAL:
- case GETPID:
- case GETNCNT:
- case GETZCNT:
- case SETVAL:
+ case GETALL:
+ {
+ ushort *array = arg.array;
+ ushort sem_io[SEMMSL];
+ int i;
+ int nsems = sma->sem_nsems;
+
+ for (i = 0; i < sma->sem_nsems; i++)
+ sem_io[i] = sma->sem_base[i].semval;
+ spin_unlock(&semary[lid].lock);
+ if (copy_to_user (array, sem_io, nsems*sizeof(ushort)))
+ return -EFAULT;
+ return 0;
+ }
+ case IPC_STAT:
+ memset(&tbuf,0,sizeof(tbuf));
+ tbuf.sem_perm = sma->sem_perm;
+ tbuf.sem_otime = sma->sem_otime;
+ tbuf.sem_ctime = sma->sem_ctime;
+ tbuf.sem_nsems = sma->sem_nsems;
+ spin_unlock(&semary[lid].lock);
+ if (copy_to_user (arg.buf, &tbuf, sizeof(tbuf)))
+ return -EFAULT;
+ return 0;
+default:
err = -EINVAL;
- if (semnum >= nsems)
- goto out;
- curr = &sma->sem_base[semnum];
- break;
}
+out_unlock:
+ spin_unlock(&semary[lid].lock);
+ return err;
+
+}
+
+int semctl_locked(int semid, int semnum, int cmd, union semun arg)
+{
+ struct semid_ds *sma;
+ int lid = semid % SEMMNI;
+ struct sem *curr;
+
+ sma = semary[lid].s;
+ if (sma == NULL)
+ return -EINVAL;
+
+ if (ipcperms (&sma->sem_perm, (cmd==SETVAL)?S_IWUGO:S_IRUGO))
+ return -EACCES;
+
+ if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI)
+ return -EIDRM;
+
+ if (semnum >= sma->sem_nsems)
+ return -EINVAL;
+
+ curr = &sma->sem_base[semnum];
switch (cmd) {
case GETVAL:
+ return curr->semval;
case GETPID:
+ return curr->sempid & 0xffff;
case GETNCNT:
+ return count_semncnt(sma,semnum);
case GETZCNT:
- case GETALL:
- err = -EACCES;
- if (ipcperms (ipcp, S_IRUGO))
- goto out;
- switch (cmd) {
- case GETVAL : err = curr->semval; goto out;
- case GETPID : err = curr->sempid & 0xffff; goto out;
- case GETNCNT: err = count_semncnt(sma,semnum); goto out;
- case GETZCNT: err = count_semzcnt(sma,semnum); goto out;
- case GETALL:
- array = arg.array;
- break;
- }
- break;
+ return count_semzcnt(sma,semnum);
case SETVAL:
- val = arg.val;
- err = -ERANGE;
+ {
+ int val = arg.val;
+ struct sem_undo *un;
if (val > SEMVMX || val < 0)
- goto out;
- break;
- case IPC_RMID:
- if (current->euid == ipcp->cuid ||
- current->euid == ipcp->uid || capable(CAP_SYS_ADMIN)) {
- freeary (id);
- err = 0;
- goto out;
- }
- err = -EPERM;
- goto out;
- case SETALL: /* arg is a pointer to an array of ushort */
- array = arg.array;
- err = -EFAULT;
- if (copy_from_user (sem_io, array, nsems*sizeof(ushort)))
- goto out;
- err = 0;
- for (i = 0; i < nsems; i++)
- if (sem_io[i] > SEMVMX) {
- err = -ERANGE;
- goto out;
- }
- break;
- case IPC_STAT:
- buf = arg.buf;
- break;
- case IPC_SET:
- buf = arg.buf;
- err = copy_from_user (&tbuf, buf, sizeof (*buf));
- if (err)
- err = -EFAULT;
- break;
- }
-
- err = -EIDRM;
- if (semary[id] == IPC_UNUSED || semary[id] == IPC_NOID)
- goto out;
- if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI)
- goto out;
+ return -ERANGE;
- switch (cmd) {
- case GETALL:
- err = -EACCES;
- if (ipcperms (ipcp, S_IRUGO))
- goto out;
- for (i = 0; i < sma->sem_nsems; i++)
- sem_io[i] = sma->sem_base[i].semval;
- if (copy_to_user (array, sem_io, nsems*sizeof(ushort)))
- err = -EFAULT;
- break;
- case SETVAL:
- err = -EACCES;
- if (ipcperms (ipcp, S_IWUGO))
- goto out;
for (un = sma->undo; un; un = un->id_next)
un->semadj[semnum] = 0;
curr->semval = val;
sma->sem_ctime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
- break;
- case IPC_SET:
- if (current->euid == ipcp->cuid ||
- current->euid == ipcp->uid || capable(CAP_SYS_ADMIN)) {
- ipcp->uid = tbuf.sem_perm.uid;
- ipcp->gid = tbuf.sem_perm.gid;
- ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
- | (tbuf.sem_perm.mode & S_IRWXUGO);
- sma->sem_ctime = CURRENT_TIME;
- err = 0;
- goto out;
- }
- err = -EPERM;
- goto out;
- case IPC_STAT:
- err = -EACCES;
- if (ipcperms (ipcp, S_IRUGO))
- goto out;
- tbuf.sem_perm = sma->sem_perm;
- tbuf.sem_otime = sma->sem_otime;
- tbuf.sem_ctime = sma->sem_ctime;
- tbuf.sem_nsems = sma->sem_nsems;
- if (copy_to_user (buf, &tbuf, sizeof(*buf)))
- err = -EFAULT;
- break;
- case SETALL:
- err = -EACCES;
+ return 0;
+ }
+ }
+ return -EINVAL;
+}
+
+int semctl_down(int semid, int semnum, int cmd, union semun arg)
+{
+ struct semid_ds *sma;
+ int err;
+ int lid = semid % SEMMNI;
+ struct semid_ds tbuf;
+ struct ipc_perm *ipcp;
+
+ if(cmd == IPC_SET) {
+ if(copy_from_user (&tbuf, arg.buf, sizeof (tbuf)))
+ return -EFAULT;
+ }
+ spin_lock(&semary[lid].lock);
+ sma = semary[lid].s;
+ err=-EINVAL;
+ if (sma == NULL)
+ goto out_unlock;
+ ipcp = &sma->sem_perm;
+
+ if(cmd == SETALL) {
+ int i;
+ struct sem_undo *un;
+ unsigned int nsems;
+ ushort sem_io[SEMMSL];
+ /* SETALL doesn't belong into this
+ * group, but I need the semaphore
+ * for atomically reading nsems
+ * and changing the semaphore values
+ */
+ err=-EACCES;
if (ipcperms (ipcp, S_IWUGO))
- goto out;
+ goto out_unlock;
+ nsems=sma->sem_nsems;
+ spin_unlock(&semary[lid].lock);
+
+ if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort)))
+ return -EFAULT;
+ for (i = 0; i < nsems; i++) {
+ if (sem_io[i] > SEMVMX) {
+ return -ERANGE;
+ }
+ }
+ /* we still own sem_lock, ie neither ownership
+ * nor permissions of the sem array could
+ * have changed. Just continue.
+ */
+ spin_lock(&semary[lid].lock);
for (i = 0; i < nsems; i++)
sma->sem_base[i].semval = sem_io[i];
for (un = sma->undo; un; un = un->id_next)
@@ -604,44 +643,169 @@
sma->sem_ctime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
+ err = 0;
+ goto out_unlock;
+ }
+
+ if (current->euid != ipcp->cuid &&
+ current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) {
+ err=-EPERM;
+ goto out_unlock;
+ }
+
+ if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI) {
+ err=-EIDRM;
+ goto out_unlock;
+ }
+ switch(cmd){
+ case IPC_RMID:
+ freeary(lid);
+ err = 0;
+ break;
+ case IPC_SET:
+ ipcp->uid = tbuf.sem_perm.uid;
+ ipcp->gid = tbuf.sem_perm.gid;
+ ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
+ | (tbuf.sem_perm.mode & S_IRWXUGO);
+ sma->sem_ctime = CURRENT_TIME;
+ err = 0;
break;
default:
err = -EINVAL;
- goto out;
}
- err = 0;
-out:
- unlock_kernel();
+
+out_unlock:
+ spin_unlock(&semary[lid].lock);
return err;
}
+asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
+{
+ int lid; /* lock id */
+ int err = -EINVAL;
+
+ if (semid < 0 || semnum < 0 || cmd < 0)
+ return -EINVAL;
+
+ lid = semid % SEMMNI;
+
+ switch(cmd) {
+ case IPC_INFO:
+ case SEM_INFO:
+ case SEM_STAT:
+ err = semctl_nolock(semid,semnum,cmd,arg);
+ return err;
+ case GETALL:
+ case IPC_STAT:
+ spin_lock(&semary[lid].lock);
+ err = semctl_locked_unlock(semid,semnum,cmd,arg);
+ return err;
+ case GETVAL:
+ case GETPID:
+ case GETNCNT:
+ case GETZCNT:
+ case SETVAL:
+ spin_lock(&semary[lid].lock);
+ err= semctl_locked(semid,semnum,cmd,arg);
+ spin_unlock(&semary[lid].lock);
+ return err;
+ case SETALL:
+ case IPC_RMID:
+ case IPC_SET:
+ down(&sem_lock);
+ err= semctl_down(semid,semnum,cmd,arg);
+ up(&sem_lock);
+ return err;
+ default:
+ return -EINVAL;
+ }
+}
+
+static struct sem_undo* freeundos(struct semid_ds *sma, struct sem_undo* un)
+{
+ struct sem_undo* u;
+ struct sem_undo** up;
+
+ for(up = ¤t->semundo;(u=*up);up=&u->proc_next) {
+ if(un==u) {
+ un=u->proc_next;
+ *up=un;
+ kfree(u);
+ return un;
+ }
+ }
+ printk ("freeundos undo list error id=%d\n", un->semid);
+ return un->proc_next;
+}
+
+static int alloc_undo(struct semid_ds *sma, struct sem_undo** unp, int semid, int alter)
+{
+ int size;
+ struct sem_undo *un;
+ int error,id;
+ id = (unsigned int) semid % SEMMNI;
+ size = sizeof(struct sem_undo) + sizeof(short)*sma->sem_nsems;
+ spin_unlock(&semary[id].lock);
+
+ un = (struct sem_undo *) kmalloc(size, GFP_KERNEL);
+ spin_lock(&semary[id].lock);
+ if (!un) {
+ return -ENOMEM;
+ }
+ sma = semary[id].s;
+ error = -EIDRM;
+ if (sma == NULL)
+ goto out;
+ if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI)
+ goto out;
+ if (size != sizeof(struct sem_undo) + sizeof(short)*sma->sem_nsems)
+ goto out;
+
+ error = -EACCES;
+ if (ipcperms(&sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
+ goto out;
+ memset(un, 0, size);
+ un->semadj = (short *) &un[1];
+ un->semid = semid;
+ un->proc_next = current->semundo;
+ current->semundo = un;
+ un->id_next = sma->undo;
+ sma->undo = un;
+ *unp = un;
+ return 0;
+out:
+ kfree(un);
+ return error;
+}
+
asmlinkage long sys_semop (int semid, struct sembuf *tsops, unsigned nsops)
{
- int id, size, error = -EINVAL;
+ int id, error = -EINVAL;
struct semid_ds *sma;
struct sembuf sops[SEMOPM], *sop;
struct sem_undo *un;
int undos = 0, decrease = 0, alter = 0;
struct sem_queue queue;
- lock_kernel();
if (nsops < 1 || semid < 0)
- goto out;
- error = -E2BIG;
+ return -EINVAL;
+
if (nsops > SEMOPM)
- goto out;
- error = -EFAULT;
+ return -E2BIG;
if (copy_from_user (sops, tsops, nsops * sizeof(*tsops)))
- goto out;
+ return -EFAULT;
+
id = (unsigned int) semid % SEMMNI;
+ spin_lock(&semary[id].lock);
+ sma = semary[id].s;
error = -EINVAL;
- if ((sma = semary[id]) == IPC_UNUSED || sma == IPC_NOID)
+ if (sma == NULL)
goto out;
error = -EIDRM;
if (sma->sem_perm.seq != (unsigned int) semid / SEMMNI)
goto out;
- error = -EFBIG;
+ error = -EFBIG;
for (sop = sops; sop < sops + nsops; sop++) {
if (sop->sem_num >= sma->sem_nsems)
goto out;
@@ -661,23 +825,19 @@
/* Make sure we have an undo structure
* for this process and this semaphore set.
*/
- for (un = current->semundo; un; un = un->proc_next)
- if (un->semid == semid)
+ un=current->semundo;
+ while(un != NULL) {
+ if(un->semid==semid)
break;
+ if(un->semid==-1)
+ un=freeundos(sma,un);
+ else
+ un=un->proc_next;
+ }
if (!un) {
- size = sizeof(struct sem_undo) + sizeof(short)*sma->sem_nsems;
- un = (struct sem_undo *) kmalloc(size, GFP_ATOMIC);
- if (!un) {
- error = -ENOMEM;
+ error = alloc_undo(sma,&un,semid,alter);
+ if(error<0)
goto out;
- }
- memset(un, 0, size);
- un->semadj = (short *) &un[1];
- un->semid = semid;
- un->proc_next = current->semundo;
- current->semundo = un;
- un->id_next = sma->undo;
- sma->undo = un;
}
} else
un = NULL;
@@ -696,6 +856,7 @@
queue.undo = un;
queue.pid = current->pid;
queue.alter = decrease;
+ queue.id = id;
current->semsleeping = &queue;
if (alter)
append_to_queue(sma ,&queue);
@@ -704,9 +865,16 @@
for (;;) {
queue.status = -EINTR;
- init_waitqueue_head(&queue.sleeper);
- interruptible_sleep_on(&queue.sleeper);
+ queue.sleeper = current;
+ current->state = TASK_INTERRUPTIBLE;
+ spin_unlock(&semary[id].lock);
+
+ schedule();
+ /* we can lock the semary even if it was
+ * deleted.
+ */
+ spin_lock(&semary[id].lock);
/*
* If queue.status == 1 we where woken up and
* have to retry else we simply return.
@@ -721,7 +889,7 @@
if (error <= 0)
break;
} else {
- error = queue.status;;
+ error = queue.status;
if (queue.prev) /* got Interrupt */
break;
/* Everything done by update_queue */
@@ -735,7 +903,7 @@
if (alter)
update_queue (sma);
out:
- unlock_kernel();
+ spin_unlock(&semary[id].lock);
return error;
}
@@ -761,27 +929,43 @@
/* If the current process was sleeping for a semaphore,
* remove it from the queue.
*/
+ /* semsleeping is part of "current", and it
+ * is never modified by another thread.
+ * No synchronization required.
+ */
if ((q = current->semsleeping)) {
+ spin_lock(&semary[current->semsleeping->id].lock);
+
if (q->prev)
remove_from_queue(q->sma,q);
current->semsleeping = NULL;
+ spin_unlock(&semary[current->semsleeping->id].lock);
}
for (up = ¤t->semundo; (u = *up); *up = u->proc_next, kfree(u)) {
- if (u->semid == -1)
- continue;
- sma = semary[(unsigned int) u->semid % SEMMNI];
- if (sma == IPC_UNUSED || sma == IPC_NOID)
+ int semid = u->semid;
+ int lid;
+ if(semid == -1)
continue;
+ lid = semid % SEMMNI;
+ spin_lock(&semary[lid].lock);
+
+ if (u->semid == -1)
+ goto next_entry;
+
+ sma = semary[lid].s;
+ if (sma == NULL)
+ goto next_entry;
if (sma->sem_perm.seq != (unsigned int) u->semid / SEMMNI)
- continue;
+ goto next_entry;
+
/* remove u from the sma->undo list */
for (unp = &sma->undo; (un = *unp); unp = &un->id_next) {
if (u == un)
goto found;
}
printk ("sem_exit undo list error id=%d\n", u->semid);
- break;
+ goto next_entry;
found:
*unp = un->id_next;
/* perform adjustments registered in u */
@@ -796,6 +980,8 @@
sma->sem_otime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
+next_entry:
+ spin_unlock(&semary[lid].lock);
}
current->semundo = NULL;
}
@@ -808,20 +994,23 @@
int i, len = 0;
len += sprintf(buffer, " key semid perms nsems uid gid cuid cgid otime ctime\n");
+ down(&sem_lock);
for(i = 0; i < SEMMNI; i++)
- if(semary[i] != IPC_UNUSED) {
+ if(semary[i].s != NULL) {
+ spin_lock(&semary[i].lock);
len += sprintf(buffer + len, "%10d %10d %4o %5u %5u %5u %5u %5u %10lu %10lu\n",
- semary[i]->sem_perm.key,
- semary[i]->sem_perm.seq * SEMMNI + i,
- semary[i]->sem_perm.mode,
- semary[i]->sem_nsems,
- semary[i]->sem_perm.uid,
- semary[i]->sem_perm.gid,
- semary[i]->sem_perm.cuid,
- semary[i]->sem_perm.cgid,
- semary[i]->sem_otime,
- semary[i]->sem_ctime);
+ semary[i].s->sem_perm.key,
+ semary[i].s->sem_perm.seq * SEMMNI + i,
+ semary[i].s->sem_perm.mode,
+ semary[i].s->sem_nsems,
+ semary[i].s->sem_perm.uid,
+ semary[i].s->sem_perm.gid,
+ semary[i].s->sem_perm.cuid,
+ semary[i].s->sem_perm.cgid,
+ semary[i].s->sem_otime,
+ semary[i].s->sem_ctime);
+ spin_unlock(&semary[i].lock);
pos += len;
if(pos < offset) {
@@ -833,6 +1022,7 @@
}
*eof = 1;
done:
+ up(&sem_lock);
*start = buffer + (offset - begin);
len -= (offset - begin);
if(len > length)
>>>>>>>>>>>>>>>>>>>
-
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