Merge commit 'v2.6.36' into kbuild/misc

Update to be able to fix a recent change to scripts/basic/docproc.c
(commit eda603f).

8 files changed, 493 insertions, 222 deletions

diff --git a/ipc/Makefile b/ipc/Makefile
index 4e1955ea815d..9075e172e52c 100644
--- a/ipc/Makefile
+++ b/ipc/Makefile
@@ -3,7 +3,7 @@
 #
 
 obj-$(CONFIG_SYSVIPC_COMPAT) += compat.o
-obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o ipcns_notifier.o
+obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o ipcns_notifier.o syscall.o
 obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o
 obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
diff --git a/ipc/compat.c b/ipc/compat.c
index ab76fb0ef844..9dc2c7d3c9e6 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -26,7 +26,6 @@
 #include <linux/init.h>
 #include <linux/msg.h>
 #include <linux/shm.h>
-#include <linux/slab.h>
 #include <linux/syscalls.h>
 
 #include <linux/mutex.h>
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index c79bd57353e7..c60e519e2917 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -32,6 +32,7 @@
 #include <linux/nsproxy.h>
 #include <linux/pid.h>
 #include <linux/ipc_namespace.h>
+#include <linux/slab.h>
 
 #include <net/sock.h>
 #include "util.h"
@@ -134,7 +135,6 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 			init_waitqueue_head(&info->wait_q);
 			INIT_LIST_HEAD(&info->e_wait_q[0].list);
 			INIT_LIST_HEAD(&info->e_wait_q[1].list);
-			info->messages = NULL;
 			info->notify_owner = NULL;
 			info->qsize = 0;
 			info->user = NULL;	/* set when all is ok */
@@ -146,26 +146,24 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 				info->attr.mq_msgsize = attr->mq_msgsize;
 			}
 			mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
+			info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
+			if (!info->messages)
+				goto out_inode;
+
 			mq_bytes = (mq_msg_tblsz +
 				(info->attr.mq_maxmsg * info->attr.mq_msgsize));
 
 			spin_lock(&mq_lock);
 			if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 		 	    u->mq_bytes + mq_bytes >
-			    p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
+			    task_rlimit(p, RLIMIT_MSGQUEUE)) {
 				spin_unlock(&mq_lock);
+				/* mqueue_evict_inode() releases info->messages */
 				goto out_inode;
 			}
 			u->mq_bytes += mq_bytes;
 			spin_unlock(&mq_lock);
 
-			info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
-			if (!info->messages) {
-				spin_lock(&mq_lock);
-				u->mq_bytes -= mq_bytes;
-				spin_unlock(&mq_lock);
-				goto out_inode;
-			}
 			/* all is ok */
 			info->user = get_uid(u);
 		} else if (S_ISDIR(mode)) {
@@ -178,7 +176,6 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 	}
 	return inode;
 out_inode:
-	make_bad_inode(inode);
 	iput(inode);
 	return NULL;
 }
@@ -187,7 +184,7 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *inode;
 	struct ipc_namespace *ns = data;
-	int error = 0;
+	int error;
 
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
@@ -205,7 +202,9 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 	if (!sb->s_root) {
 		iput(inode);
 		error = -ENOMEM;
+		goto out;
 	}
+	error = 0;
 
 out:
 	return error;
@@ -242,7 +241,7 @@ static void mqueue_destroy_inode(struct inode *inode)
 	kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 }
 
-static void mqueue_delete_inode(struct inode *inode)
+static void mqueue_evict_inode(struct inode *inode)
 {
 	struct mqueue_inode_info *info;
 	struct user_struct *user;
@@ -250,10 +249,11 @@ static void mqueue_delete_inode(struct inode *inode)
 	int i;
 	struct ipc_namespace *ipc_ns;
 
-	if (S_ISDIR(inode->i_mode)) {
-		clear_inode(inode);
+	end_writeback(inode);
+
+	if (S_ISDIR(inode->i_mode))
 		return;
-	}
+
 	ipc_ns = get_ns_from_inode(inode);
 	info = MQUEUE_I(inode);
 	spin_lock(&info->lock);
@@ -262,10 +262,9 @@ static void mqueue_delete_inode(struct inode *inode)
 	kfree(info->messages);
 	spin_unlock(&info->lock);
 
-	clear_inode(inode);
-
-	mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
-		   (info->attr.mq_maxmsg * info->attr.mq_msgsize));
+	/* Total amount of bytes accounted for the mqueue */
+	mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *)
+	    + info->attr.mq_msgsize);
 	user = info->user;
 	if (user) {
 		spin_lock(&mq_lock);
@@ -428,7 +427,7 @@ static void wq_add(struct mqueue_inode_info *info, int sr,
  * sr: SEND or RECV
  */
 static int wq_sleep(struct mqueue_inode_info *info, int sr,
-			long timeout, struct ext_wait_queue *ewp)
+		    ktime_t *timeout, struct ext_wait_queue *ewp)
 {
 	int retval;
 	signed long time;
@@ -439,7 +438,8 @@ static int wq_sleep(struct mqueue_inode_info *info, int sr,
 		set_current_state(TASK_INTERRUPTIBLE);
 
 		spin_unlock(&info->lock);
-		time = schedule_timeout(timeout);
+		time = schedule_hrtimeout_range_clock(timeout,
+		    HRTIMER_MODE_ABS, 0, CLOCK_REALTIME);
 
 		while (ewp->state == STATE_PENDING)
 			cpu_relax();
@@ -551,31 +551,16 @@ static void __do_notify(struct mqueue_inode_info *info)
 	wake_up(&info->wait_q);
 }
 
-static long prepare_timeout(struct timespec *p)
+static int prepare_timeout(const struct timespec __user *u_abs_timeout,
+			   ktime_t *expires, struct timespec *ts)
 {
-	struct timespec nowts;
-	long timeout;
-
-	if (p) {
-		if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
-			|| p->tv_nsec >= NSEC_PER_SEC))
-			return -EINVAL;
-		nowts = CURRENT_TIME;
-		/* first subtract as jiffies can't be too big */
-		p->tv_sec -= nowts.tv_sec;
-		if (p->tv_nsec < nowts.tv_nsec) {
-			p->tv_nsec += NSEC_PER_SEC;
-			p->tv_sec--;
-		}
-		p->tv_nsec -= nowts.tv_nsec;
-		if (p->tv_sec < 0)
-			return 0;
-
-		timeout = timespec_to_jiffies(p) + 1;
-	} else
-		return MAX_SCHEDULE_TIMEOUT;
+	if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
+		return -EFAULT;
+	if (!timespec_valid(ts))
+		return -EINVAL;
 
-	return timeout;
+	*expires = timespec_to_ktime(*ts);
+	return 0;
 }
 
 static void remove_notification(struct mqueue_inode_info *info)
@@ -604,8 +589,8 @@ static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 	/* check for overflow */
 	if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 		return 0;
-	if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
-	    (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
+	if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize
+	    + sizeof (struct msg_msg *))) <
 	    (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
 		return 0;
 	return 1;
@@ -623,9 +608,10 @@ static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
 	int ret;
 
 	if (attr) {
-		ret = -EINVAL;
-		if (!mq_attr_ok(ipc_ns, attr))
+		if (!mq_attr_ok(ipc_ns, attr)) {
+			ret = -EINVAL;
 			goto out;
+		}
 		/* store for use during create */
 		dentry->d_fsdata = attr;
 	}
@@ -659,24 +645,28 @@ out:
 static struct file *do_open(struct ipc_namespace *ipc_ns,
 				struct dentry *dentry, int oflag)
 {
+	int ret;
 	const struct cred *cred = current_cred();
 
 	static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 						  MAY_READ | MAY_WRITE };
 
 	if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
-		dput(dentry);
-		mntput(ipc_ns->mq_mnt);
-		return ERR_PTR(-EINVAL);
+		ret = -EINVAL;
+		goto err;
 	}
 
 	if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
-		dput(dentry);
-		mntput(ipc_ns->mq_mnt);
-		return ERR_PTR(-EACCES);
+		ret = -EACCES;
+		goto err;
 	}
 
 	return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
+
+err:
+	dput(dentry);
+	mntput(ipc_ns->mq_mnt);
+	return ERR_PTR(ret);
 }
 
 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
@@ -705,16 +695,17 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
 	dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 	if (IS_ERR(dentry)) {
 		error = PTR_ERR(dentry);
-		goto out_err;
+		goto out_putfd;
 	}
 	mntget(ipc_ns->mq_mnt);
 
 	if (oflag & O_CREAT) {
 		if (dentry->d_inode) {	/* entry already exists */
 			audit_inode(name, dentry);
-			error = -EEXIST;
-			if (oflag & O_EXCL)
+			if (oflag & O_EXCL) {
+				error = -EEXIST;
 				goto out;
+			}
 			filp = do_open(ipc_ns, dentry, oflag);
 		} else {
 			filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
@@ -722,9 +713,10 @@ SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
 						u_attr ? &attr : NULL);
 		}
 	} else {
-		error = -ENOENT;
-		if (!dentry->d_inode)
+		if (!dentry->d_inode) {
+			error = -ENOENT;
 			goto out;
+		}
 		audit_inode(name, dentry);
 		filp = do_open(ipc_ns, dentry, oflag);
 	}
@@ -742,7 +734,6 @@ out:
 	mntput(ipc_ns->mq_mnt);
 out_putfd:
 	put_unused_fd(fd);
-out_err:
 	fd = error;
 out_upsem:
 	mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
@@ -855,36 +846,40 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 	struct ext_wait_queue *receiver;
 	struct msg_msg *msg_ptr;
 	struct mqueue_inode_info *info;
-	struct timespec ts, *p = NULL;
-	long timeout;
+	ktime_t expires, *timeout = NULL;
+	struct timespec ts;
 	int ret;
 
 	if (u_abs_timeout) {
-		if (copy_from_user(&ts, u_abs_timeout, 
-					sizeof(struct timespec)))
-			return -EFAULT;
-		p = &ts;
+		int res = prepare_timeout(u_abs_timeout, &expires, &ts);
+		if (res)
+			return res;
+		timeout = &expires;
 	}
 
 	if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 		return -EINVAL;
 
-	audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
-	timeout = prepare_timeout(p);
+	audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
 
-	ret = -EBADF;
 	filp = fget(mqdes);
-	if (unlikely(!filp))
+	if (unlikely(!filp)) {
+		ret = -EBADF;
 		goto out;
+	}
 
 	inode = filp->f_path.dentry->d_inode;
-	if (unlikely(filp->f_op != &mqueue_file_operations))
+	if (unlikely(filp->f_op != &mqueue_file_operations)) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 	info = MQUEUE_I(inode);
 	audit_inode(NULL, filp->f_path.dentry);
 
-	if (unlikely(!(filp->f_mode & FMODE_WRITE)))
+	if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 
 	if (unlikely(msg_len > info->attr.mq_msgsize)) {
 		ret = -EMSGSIZE;
@@ -907,9 +902,6 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 		if (filp->f_flags & O_NONBLOCK) {
 			spin_unlock(&info->lock);
 			ret = -EAGAIN;
-		} else if (unlikely(timeout < 0)) {
-			spin_unlock(&info->lock);
-			ret = timeout;
 		} else {
 			wait.task = current;
 			wait.msg = (void *) msg_ptr;
@@ -942,38 +934,42 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
 		size_t, msg_len, unsigned int __user *, u_msg_prio,
 		const struct timespec __user *, u_abs_timeout)
 {
-	long timeout;
 	ssize_t ret;
 	struct msg_msg *msg_ptr;
 	struct file *filp;
 	struct inode *inode;
 	struct mqueue_inode_info *info;
 	struct ext_wait_queue wait;
-	struct timespec ts, *p = NULL;
+	ktime_t expires, *timeout = NULL;
+	struct timespec ts;
 
 	if (u_abs_timeout) {
-		if (copy_from_user(&ts, u_abs_timeout, 
-					sizeof(struct timespec)))
-			return -EFAULT;
-		p = &ts;
+		int res = prepare_timeout(u_abs_timeout, &expires, &ts);
+		if (res)
+			return res;
+		timeout = &expires;
 	}
 
-	audit_mq_sendrecv(mqdes, msg_len, 0, p);
-	timeout = prepare_timeout(p);
+	audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
 
-	ret = -EBADF;
 	filp = fget(mqdes);
-	if (unlikely(!filp))
+	if (unlikely(!filp)) {
+		ret = -EBADF;
 		goto out;
+	}
 
 	inode = filp->f_path.dentry->d_inode;
-	if (unlikely(filp->f_op != &mqueue_file_operations))
+	if (unlikely(filp->f_op != &mqueue_file_operations)) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 	info = MQUEUE_I(inode);
 	audit_inode(NULL, filp->f_path.dentry);
 
-	if (unlikely(!(filp->f_mode & FMODE_READ)))
+	if (unlikely(!(filp->f_mode & FMODE_READ))) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 
 	/* checks if buffer is big enough */
 	if (unlikely(msg_len < info->attr.mq_msgsize)) {
@@ -986,11 +982,6 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
 		if (filp->f_flags & O_NONBLOCK) {
 			spin_unlock(&info->lock);
 			ret = -EAGAIN;
-			msg_ptr = NULL;
-		} else if (unlikely(timeout < 0)) {
-			spin_unlock(&info->lock);
-			ret = timeout;
-			msg_ptr = NULL;
 		} else {
 			wait.task = current;
 			wait.state = STATE_NONE;
@@ -1063,13 +1054,14 @@ SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
 
 			/* create the notify skb */
 			nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
-			ret = -ENOMEM;
-			if (!nc)
+			if (!nc) {
+				ret = -ENOMEM;
 				goto out;
-			ret = -EFAULT;
+			}
 			if (copy_from_user(nc->data,
 					notification.sigev_value.sival_ptr,
 					NOTIFY_COOKIE_LEN)) {
+				ret = -EFAULT;
 				goto out;
 			}
 
@@ -1078,9 +1070,10 @@ SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
 			/* and attach it to the socket */
 retry:
 			filp = fget(notification.sigev_signo);
-			ret = -EBADF;
-			if (!filp)
+			if (!filp) {
+				ret = -EBADF;
 				goto out;
+			}
 			sock = netlink_getsockbyfilp(filp);
 			fput(filp);
 			if (IS_ERR(sock)) {
@@ -1092,7 +1085,7 @@ retry:
 			timeo = MAX_SCHEDULE_TIMEOUT;
 			ret = netlink_attachskb(sock, nc, &timeo, NULL);
 			if (ret == 1)
-		       		goto retry;
+				goto retry;
 			if (ret) {
 				sock = NULL;
 				nc = NULL;
@@ -1101,14 +1094,17 @@ retry:
 		}
 	}
 
-	ret = -EBADF;
 	filp = fget(mqdes);
-	if (!filp)
+	if (!filp) {
+		ret = -EBADF;
 		goto out;
+	}
 
 	inode = filp->f_path.dentry->d_inode;
-	if (unlikely(filp->f_op != &mqueue_file_operations))
+	if (unlikely(filp->f_op != &mqueue_file_operations)) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 	info = MQUEUE_I(inode);
 
 	ret = 0;
@@ -1171,14 +1167,17 @@ SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
 			return -EINVAL;
 	}
 
-	ret = -EBADF;
 	filp = fget(mqdes);
-	if (!filp)
+	if (!filp) {
+		ret = -EBADF;
 		goto out;
+	}
 
 	inode = filp->f_path.dentry->d_inode;
-	if (unlikely(filp->f_op != &mqueue_file_operations))
+	if (unlikely(filp->f_op != &mqueue_file_operations)) {
+		ret = -EBADF;
 		goto out_fput;
+	}
 	info = MQUEUE_I(inode);
 
 	spin_lock(&info->lock);
@@ -1225,9 +1224,8 @@ static const struct file_operations mqueue_file_operations = {
 static const struct super_operations mqueue_super_ops = {
 	.alloc_inode = mqueue_alloc_inode,
 	.destroy_inode = mqueue_destroy_inode,
+	.evict_inode = mqueue_evict_inode,
 	.statfs = simple_statfs,
-	.delete_inode = mqueue_delete_inode,
-	.drop_inode = generic_delete_inode,
 };
 
 static struct file_system_type mqueue_fs_type = {
@@ -1272,7 +1270,7 @@ static int __init init_mqueue_fs(void)
 	if (mqueue_inode_cachep == NULL)
 		return -ENOMEM;
 
-	/* ignore failues - they are not fatal */
+	/* ignore failures - they are not fatal */
 	mq_sysctl_table = mq_register_sysctl_table();
 
 	error = register_filesystem(&mqueue_fs_type);
diff --git a/ipc/msg.c b/ipc/msg.c
index af42ef8900a6..747b65507a91 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -23,7 +23,6 @@
  */
 
 #include <linux/capability.h>
-#include <linux/slab.h>
 #include <linux/msg.h>
 #include <linux/spinlock.h>
 #include <linux/init.h>
@@ -346,19 +345,19 @@ copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
 		out.msg_rtime		= in->msg_rtime;
 		out.msg_ctime		= in->msg_ctime;
 
-		if (in->msg_cbytes > USHORT_MAX)
-			out.msg_cbytes	= USHORT_MAX;
+		if (in->msg_cbytes > USHRT_MAX)
+			out.msg_cbytes	= USHRT_MAX;
 		else
 			out.msg_cbytes	= in->msg_cbytes;
 		out.msg_lcbytes		= in->msg_cbytes;
 
-		if (in->msg_qnum > USHORT_MAX)
-			out.msg_qnum	= USHORT_MAX;
+		if (in->msg_qnum > USHRT_MAX)
+			out.msg_qnum	= USHRT_MAX;
 		else
 			out.msg_qnum	= in->msg_qnum;
 
-		if (in->msg_qbytes > USHORT_MAX)
-			out.msg_qbytes	= USHORT_MAX;
+		if (in->msg_qbytes > USHRT_MAX)
+			out.msg_qbytes	= USHRT_MAX;
 		else
 			out.msg_qbytes	= in->msg_qbytes;
 		out.msg_lqbytes		= in->msg_qbytes;
diff --git a/ipc/sem.c b/ipc/sem.c
index dbef95b15941..0e0d49bbb867 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -3,56 +3,6 @@
  * Copyright (C) 1992 Krishna Balasubramanian
  * Copyright (C) 1995 Eric Schenk, Bruno Haible
  *
- * IMPLEMENTATION NOTES ON CODE REWRITE (Eric Schenk, January 1995):
- * This code underwent a massive rewrite in order to solve some problems
- * with the original code. In particular the original code failed to
- * wake up processes that were waiting for semval to go to 0 if the
- * value went to 0 and was then incremented rapidly enough. In solving
- * this problem I have also modified the implementation so that it
- * processes pending operations in a FIFO manner, thus give a guarantee
- * that processes waiting for a lock on the semaphore won't starve
- * unless another locking process fails to unlock.
- * In addition the following two changes in behavior have been introduced:
- * - The original implementation of semop returned the value
- *   last semaphore element examined on success. This does not
- *   match the manual page specifications, and effectively
- *   allows the user to read the semaphore even if they do not
- *   have read permissions. The implementation now returns 0
- *   on success as stated in the manual page.
- * - There is some confusion over whether the set of undo adjustments
- *   to be performed at exit should be done in an atomic manner.
- *   That is, if we are attempting to decrement the semval should we queue
- *   up and wait until we can do so legally?
- *   The original implementation attempted to do this.
- *   The current implementation does not do so. This is because I don't
- *   think it is the right thing (TM) to do, and because I couldn't
- *   see a clean way to get the old behavior with the new design.
- *   The POSIX standard and SVID should be consulted to determine
- *   what behavior is mandated.
- *
- * Further notes on refinement (Christoph Rohland, December 1998):
- * - The POSIX standard says, that the undo adjustments simply should
- *   redo. So the current implementation is o.K.
- * - The previous code had two flaws:
- *   1) It actively gave the semaphore to the next waiting process
- *      sleeping on the semaphore. Since this process did not have the
- *      cpu this led to many unnecessary context switches and bad
- *      performance. Now we only check which process should be able to
- *      get the semaphore and if this process wants to reduce some
- *      semaphore value we simply wake it up without doing the
- *      operation. So it has to try to get it later. Thus e.g. the
- *      running process may reacquire the semaphore during the current
- *      time slice. If it only waits for zero or increases the semaphore,
- *      we do the operation in advance and wake it up.
- *   2) It did not wake up all zero waiting processes. We try to do
- *      better but only get the semops right which only wait for zero or
- *      increase. If there are decrement operations in the operations
- *      array we do the same as before.
- *
- * With the incarnation of O(1) scheduler, it becomes unnecessary to perform
- * check/retry algorithm for waking up blocked processes as the new scheduler
- * is better at handling thread switch than the old one.
- *
  * /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
  *
  * SMP-threaded, sysctl's added
@@ -61,6 +11,8 @@
  * (c) 2001 Red Hat Inc
  * Lockless wakeup
  * (c) 2003 Manfred Spraul <manfred@colorfullife.com>
+ * Further wakeup optimizations, documentation
+ * (c) 2010 Manfred Spraul <manfred@colorfullife.com>
  *
  * support for audit of ipc object properties and permission changes
  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
@@ -68,6 +20,57 @@
  * namespaces support
  * OpenVZ, SWsoft Inc.
  * Pavel Emelianov <xemul@openvz.org>
+ *
+ * Implementation notes: (May 2010)
+ * This file implements System V semaphores.
+ *
+ * User space visible behavior:
+ * - FIFO ordering for semop() operations (just FIFO, not starvation
+ *   protection)
+ * - multiple semaphore operations that alter the same semaphore in
+ *   one semop() are handled.
+ * - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and
+ *   SETALL calls.
+ * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO.
+ * - undo adjustments at process exit are limited to 0..SEMVMX.
+ * - namespace are supported.
+ * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing
+ *   to /proc/sys/kernel/sem.
+ * - statistics about the usage are reported in /proc/sysvipc/sem.
+ *
+ * Internals:
+ * - scalability:
+ *   - all global variables are read-mostly.
+ *   - semop() calls and semctl(RMID) are synchronized by RCU.
+ *   - most operations do write operations (actually: spin_lock calls) to
+ *     the per-semaphore array structure.
+ *   Thus: Perfect SMP scaling between independent semaphore arrays.
+ *         If multiple semaphores in one array are used, then cache line
+ *         trashing on the semaphore array spinlock will limit the scaling.
+ * - semncnt and semzcnt are calculated on demand in count_semncnt() and
+ *   count_semzcnt()
+ * - the task that performs a successful semop() scans the list of all
+ *   sleeping tasks and completes any pending operations that can be fulfilled.
+ *   Semaphores are actively given to waiting tasks (necessary for FIFO).
+ *   (see update_queue())
+ * - To improve the scalability, the actual wake-up calls are performed after
+ *   dropping all locks. (see wake_up_sem_queue_prepare(),
+ *   wake_up_sem_queue_do())
+ * - All work is done by the waker, the woken up task does not have to do
+ *   anything - not even acquiring a lock or dropping a refcount.
+ * - A woken up task may not even touch the semaphore array anymore, it may
+ *   have been destroyed already by a semctl(RMID).
+ * - The synchronizations between wake-ups due to a timeout/signal and a
+ *   wake-up due to a completed semaphore operation is achieved by using an
+ *   intermediate state (IN_WAKEUP).
+ * - UNDO values are stored in an array (one per process and per
+ *   semaphore array, lazily allocated). For backwards compatibility, multiple
+ *   modes for the UNDO variables are supported (per process, per thread)
+ *   (see copy_semundo, CLONE_SYSVSEM)
+ * - There are two lists of the pending operations: a per-array list
+ *   and per-semaphore list (stored in the array). This allows to achieve FIFO
+ *   ordering without always scanning all pending operations.
+ *   The worst-case behavior is nevertheless O(N^2) for N wakeups.
  */
 
 #include <linux/slab.h>
@@ -381,7 +384,6 @@ static int try_atomic_semop (struct sem_array * sma, struct sembuf * sops,
 		sop--;
 	}
 	
-	sma->sem_otime = get_seconds();
 	return 0;
 
 out_of_range:
@@ -404,25 +406,51 @@ undo:
 	return result;
 }
 
-/*
- * Wake up a process waiting on the sem queue with a given error.
- * The queue is invalid (may not be accessed) after the function returns.
+/** wake_up_sem_queue_prepare(q, error): Prepare wake-up
+ * @q: queue entry that must be signaled
+ * @error: Error value for the signal
+ *
+ * Prepare the wake-up of the queue entry q.
  */
-static void wake_up_sem_queue(struct sem_queue *q, int error)
+static void wake_up_sem_queue_prepare(struct list_head *pt,
+				struct sem_queue *q, int error)
 {
-	/*
-	 * Hold preempt off so that we don't get preempted and have the
-	 * wakee busy-wait until we're scheduled back on. We're holding
-	 * locks here so it may not strictly be needed, however if the
-	 * locks become preemptible then this prevents such a problem.
-	 */
-	preempt_disable();
+	if (list_empty(pt)) {
+		/*
+		 * Hold preempt off so that we don't get preempted and have the
+		 * wakee busy-wait until we're scheduled back on.
+		 */
+		preempt_disable();
+	}
 	q->status = IN_WAKEUP;
-	wake_up_process(q->sleeper);
-	/* hands-off: q can disappear immediately after writing q->status. */
-	smp_wmb();
-	q->status = error;
-	preempt_enable();
+	q->pid = error;
+
+	list_add_tail(&q->simple_list, pt);
+}
+
+/**
+ * wake_up_sem_queue_do(pt) - do the actual wake-up
+ * @pt: list of tasks to be woken up
+ *
+ * Do the actual wake-up.
+ * The function is called without any locks held, thus the semaphore array
+ * could be destroyed already and the tasks can disappear as soon as the
+ * status is set to the actual return code.
+ */
+static void wake_up_sem_queue_do(struct list_head *pt)
+{
+	struct sem_queue *q, *t;
+	int did_something;
+
+	did_something = !list_empty(pt);
+	list_for_each_entry_safe(q, t, pt, simple_list) {
+		wake_up_process(q->sleeper);
+		/* q can disappear immediately after writing q->status. */
+		smp_wmb();
+		q->status = q->pid;
+	}
+	if (did_something)
+		preempt_enable();
 }
 
 static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
@@ -434,22 +462,90 @@ static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
 		sma->complex_count--;
 }
 
+/** check_restart(sma, q)
+ * @sma: semaphore array
+ * @q: the operation that just completed
+ *
+ * update_queue is O(N^2) when it restarts scanning the whole queue of
+ * waiting operations. Therefore this function checks if the restart is
+ * really necessary. It is called after a previously waiting operation
+ * was completed.
+ */
+static int check_restart(struct sem_array *sma, struct sem_queue *q)
+{
+	struct sem *curr;
+	struct sem_queue *h;
+
+	/* if the operation didn't modify the array, then no restart */
+	if (q->alter == 0)
+		return 0;
+
+	/* pending complex operations are too difficult to analyse */
+	if (sma->complex_count)
+		return 1;
+
+	/* we were a sleeping complex operation. Too difficult */
+	if (q->nsops > 1)
+		return 1;
+
+	curr = sma->sem_base + q->sops[0].sem_num;
+
+	/* No-one waits on this queue */
+	if (list_empty(&curr->sem_pending))
+		return 0;
+
+	/* the new semaphore value */
+	if (curr->semval) {
+		/* It is impossible that someone waits for the new value:
+		 * - q is a previously sleeping simple operation that
+		 *   altered the array. It must be a decrement, because
+		 *   simple increments never sleep.
+		 * - The value is not 0, thus wait-for-zero won't proceed.
+		 * - If there are older (higher priority) decrements
+		 *   in the queue, then they have observed the original
+		 *   semval value and couldn't proceed. The operation
+		 *   decremented to value - thus they won't proceed either.
+		 */
+		BUG_ON(q->sops[0].sem_op >= 0);
+		return 0;
+	}
+	/*
+	 * semval is 0. Check if there are wait-for-zero semops.
+	 * They must be the first entries in the per-semaphore simple queue
+	 */
+	h = list_first_entry(&curr->sem_pending, struct sem_queue, simple_list);
+	BUG_ON(h->nsops != 1);
+	BUG_ON(h->sops[0].sem_num != q->sops[0].sem_num);
+
+	/* Yes, there is a wait-for-zero semop. Restart */
+	if (h->sops[0].sem_op == 0)
+		return 1;
+
+	/* Again - no-one is waiting for the new value. */
+	return 0;
+}
+
 
 /**
  * update_queue(sma, semnum): Look for tasks that can be completed.
  * @sma: semaphore array.
  * @semnum: semaphore that was modified.
+ * @pt: list head for the tasks that must be woken up.
  *
  * update_queue must be called after a semaphore in a semaphore array
  * was modified. If multiple semaphore were modified, then @semnum
  * must be set to -1.
+ * The tasks that must be woken up are added to @pt. The return code
+ * is stored in q->pid.
+ * The function return 1 if at least one semop was completed successfully.
  */
-static void update_queue(struct sem_array *sma, int semnum)
+static int update_queue(struct sem_array *sma, int semnum, struct list_head *pt)
 {
 	struct sem_queue *q;
 	struct list_head *walk;
 	struct list_head *pending_list;
 	int offset;
+	int semop_completed = 0;
 
 	/* if there are complex operations around, then knowing the semaphore
 	 * that was modified doesn't help us. Assume that multiple semaphores
@@ -469,7 +565,7 @@ static void update_queue(struct sem_array *sma, int semnum)
 again:
 	walk = pending_list->next;
 	while (walk != pending_list) {
-		int error, alter;
+		int error, restart;
 
 		q = (struct sem_queue *)((char *)walk - offset);
 		walk = walk->next;
@@ -494,22 +590,58 @@ again:
 
 		unlink_queue(sma, q);
 
-		/*
-		 * The next operation that must be checked depends on the type
-		 * of the completed operation:
-		 * - if the operation modified the array, then restart from the
-		 *   head of the queue and check for threads that might be
-		 *   waiting for the new semaphore values.
-		 * - if the operation didn't modify the array, then just
-		 *   continue.
-		 */
-		alter = q->alter;
-		wake_up_sem_queue(q, error);
-		if (alter && !error)
+		if (error) {
+			restart = 0;
+		} else {
+			semop_completed = 1;
+			restart = check_restart(sma, q);
+		}
+
+		wake_up_sem_queue_prepare(pt, q, error);
+		if (restart)
 			goto again;
 	}
+	return semop_completed;
+}
+
+/**
+ * do_smart_update(sma, sops, nsops, otime, pt) - optimized update_queue
+ * @sma: semaphore array
+ * @sops: operations that were performed
+ * @nsops: number of operations
+ * @otime: force setting otime
+ * @pt: list head of the tasks that must be woken up.
+ *
+ * do_smart_update() does the required called to update_queue, based on the
+ * actual changes that were performed on the semaphore array.
+ * Note that the function does not do the actual wake-up: the caller is
+ * responsible for calling wake_up_sem_queue_do(@pt).
+ * It is safe to perform this call after dropping all locks.
+ */
+static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops,
+			int otime, struct list_head *pt)
+{
+	int i;
+
+	if (sma->complex_count || sops == NULL) {
+		if (update_queue(sma, -1, pt))
+			otime = 1;
+		goto done;
+	}
+
+	for (i = 0; i < nsops; i++) {
+		if (sops[i].sem_op > 0 ||
+			(sops[i].sem_op < 0 &&
+				sma->sem_base[sops[i].sem_num].semval == 0))
+			if (update_queue(sma, sops[i].sem_num, pt))
+				otime = 1;
+	}
+done:
+	if (otime)
+		sma->sem_otime = get_seconds();
 }
 
+
 /* The following counts are associated to each semaphore:
  *   semncnt        number of tasks waiting on semval being nonzero
  *   semzcnt        number of tasks waiting on semval being zero
@@ -572,6 +704,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 	struct sem_undo *un, *tu;
 	struct sem_queue *q, *tq;
 	struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
+	struct list_head tasks;
 
 	/* Free the existing undo structures for this semaphore set.  */
 	assert_spin_locked(&sma->sem_perm.lock);
@@ -585,15 +718,17 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 	}
 
 	/* Wake up all pending processes and let them fail with EIDRM. */
+	INIT_LIST_HEAD(&tasks);
 	list_for_each_entry_safe(q, tq, &sma->sem_pending, list) {
 		unlink_queue(sma, q);
-		wake_up_sem_queue(q, -EIDRM);
+		wake_up_sem_queue_prepare(&tasks, q, -EIDRM);
 	}
 
 	/* Remove the semaphore set from the IDR */
 	sem_rmid(ns, sma);
 	sem_unlock(sma);
 
+	wake_up_sem_queue_do(&tasks);
 	ns->used_sems -= sma->sem_nsems;
 	security_sem_free(sma);
 	ipc_rcu_putref(sma);
@@ -608,6 +743,8 @@ static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in,
 	    {
 		struct semid_ds out;
 
+		memset(&out, 0, sizeof(out));
+
 		ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm);
 
 		out.sem_otime	= in->sem_otime;
@@ -715,11 +852,13 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
 	ushort fast_sem_io[SEMMSL_FAST];
 	ushort* sem_io = fast_sem_io;
 	int nsems;
+	struct list_head tasks;
 
 	sma = sem_lock_check(ns, semid);
 	if (IS_ERR(sma))
 		return PTR_ERR(sma);
 
+	INIT_LIST_HEAD(&tasks);
 	nsems = sma->sem_nsems;
 
 	err = -EACCES;
@@ -807,7 +946,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
 		}
 		sma->sem_ctime = get_seconds();
 		/* maybe some queued-up processes were waiting for this */
-		update_queue(sma, -1);
+		do_smart_update(sma, NULL, 0, 0, &tasks);
 		err = 0;
 		goto out_unlock;
 	}
@@ -849,13 +988,15 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
 		curr->sempid = task_tgid_vnr(current);
 		sma->sem_ctime = get_seconds();
 		/* maybe some queued-up processes were waiting for this */
-		update_queue(sma, semnum);
+		do_smart_update(sma, NULL, 0, 0, &tasks);
 		err = 0;
 		goto out_unlock;
 	}
 	}
 out_unlock:
 	sem_unlock(sma);
+	wake_up_sem_queue_do(&tasks);
+
 out_free:
 	if(sem_io != fast_sem_io)
 		ipc_free(sem_io, sizeof(ushort)*nsems);
@@ -1069,7 +1210,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
 	/* step 1: figure out the size of the semaphore array */
 	sma = sem_lock_check(ns, semid);
 	if (IS_ERR(sma))
-		return ERR_PTR(PTR_ERR(sma));
+		return ERR_CAST(sma);
 
 	nsems = sma->sem_nsems;
 	sem_getref_and_unlock(sma);
@@ -1117,6 +1258,33 @@ out:
 	return un;
 }
 
+
+/**
+ * get_queue_result - Retrieve the result code from sem_queue
+ * @q: Pointer to queue structure
+ *
+ * Retrieve the return code from the pending queue. If IN_WAKEUP is found in
+ * q->status, then we must loop until the value is replaced with the final
+ * value: This may happen if a task is woken up by an unrelated event (e.g.
+ * signal) and in parallel the task is woken up by another task because it got
+ * the requested semaphores.
+ *
+ * The function can be called with or without holding the semaphore spinlock.
+ */
+static int get_queue_result(struct sem_queue *q)
+{
+	int error;
+
+	error = q->status;
+	while (unlikely(error == IN_WAKEUP)) {
+		cpu_relax();
+		error = q->status;
+	}
+
+	return error;
+}
+
+
 SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 		unsigned, nsops, const struct timespec __user *, timeout)
 {
@@ -1129,6 +1297,7 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 	struct sem_queue queue;
 	unsigned long jiffies_left = 0;
 	struct ipc_namespace *ns;
+	struct list_head tasks;
 
 	ns = current->nsproxy->ipc_ns;
 
@@ -1177,6 +1346,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 	} else
 		un = NULL;
 
+	INIT_LIST_HEAD(&tasks);
+
 	sma = sem_lock_check(ns, semid);
 	if (IS_ERR(sma)) {
 		if (un)
@@ -1225,7 +1396,7 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 	error = try_atomic_semop (sma, sops, nsops, un, task_tgid_vnr(current));
 	if (error <= 0) {
 		if (alter && error == 0)
-			update_queue(sma, (nsops == 1) ? sops[0].sem_num : -1);
+			do_smart_update(sma, sops, nsops, 1, &tasks);
 
 		goto out_unlock_free;
 	}
@@ -1267,15 +1438,18 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 	else
 		schedule();
 
-	error = queue.status;
-	while(unlikely(error == IN_WAKEUP)) {
-		cpu_relax();
-		error = queue.status;
-	}
+	error = get_queue_result(&queue);
 
 	if (error != -EINTR) {
 		/* fast path: update_queue already obtained all requested
-		 * resources */
+		 * resources.
+		 * Perform a smp_mb(): User space could assume that semop()
+		 * is a memory barrier: Without the mb(), the cpu could
+		 * speculatively read in user space stale data that was
+		 * overwritten by the previous owner of the semaphore.
+		 */
+		smp_mb();
+
 		goto out_free;
 	}
 
@@ -1285,10 +1459,12 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 		goto out_free;
 	}
 
+	error = get_queue_result(&queue);
+
 	/*
 	 * If queue.status != -EINTR we are woken up by another process
 	 */
-	error = queue.status;
+
 	if (error != -EINTR) {
 		goto out_unlock_free;
 	}
@@ -1302,6 +1478,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 
 out_unlock_free:
 	sem_unlock(sma);
+
+	wake_up_sem_queue_do(&tasks);
 out_free:
 	if(sops != fast_sops)
 		kfree(sops);
@@ -1362,6 +1540,7 @@ void exit_sem(struct task_struct *tsk)
 	for (;;) {
 		struct sem_array *sma;
 		struct sem_undo *un;
+		struct list_head tasks;
 		int semid;
 		int i;
 
@@ -1425,10 +1604,11 @@ void exit_sem(struct task_struct *tsk)
 				semaphore->sempid = task_tgid_vnr(current);
 			}
 		}
-		sma->sem_otime = get_seconds();
 		/* maybe some queued-up processes were waiting for this */
-		update_queue(sma, -1);
+		INIT_LIST_HEAD(&tasks);
+		do_smart_update(sma, NULL, 0, 1, &tasks);
 		sem_unlock(sma);
+		wake_up_sem_queue_do(&tasks);
 
 		call_rcu(&un->rcu, free_un);
 	}
diff --git a/ipc/shm.c b/ipc/shm.c
index 23256b855819..52ed77eb9713 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -273,16 +273,13 @@ static int shm_release(struct inode *ino, struct file *file)
 	return 0;
 }
 
-static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
+static int shm_fsync(struct file *file, int datasync)
 {
-	int (*fsync) (struct file *, struct dentry *, int datasync);
 	struct shm_file_data *sfd = shm_file_data(file);
-	int ret = -EINVAL;
 
-	fsync = sfd->file->f_op->fsync;
-	if (fsync)
-		ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
-	return ret;
+	if (!sfd->file->f_op->fsync)
+		return -EINVAL;
+	return sfd->file->f_op->fsync(sfd->file, datasync);
 }
 
 static unsigned long shm_get_unmapped_area(struct file *file,
@@ -764,8 +761,7 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 			if (euid != shp->shm_perm.uid &&
 			    euid != shp->shm_perm.cuid)
 				goto out_unlock;
-			if (cmd == SHM_LOCK &&
-			    !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
+			if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 				goto out_unlock;
 		}
 
diff --git a/ipc/syscall.c b/ipc/syscall.c
new file mode 100644
index 000000000000..1d6f53f6b562
--- /dev/null
+++ b/ipc/syscall.c
@@ -0,0 +1,99 @@
+/*
+ * sys_ipc() is the old de-multiplexer for the SysV IPC calls.
+ *
+ * This is really horribly ugly, and new architectures should just wire up
+ * the individual syscalls instead.
+ */
+#include <linux/unistd.h>
+
+#ifdef __ARCH_WANT_SYS_IPC
+#include <linux/errno.h>
+#include <linux/ipc.h>
+#include <linux/shm.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second,
+		unsigned long, third, void __user *, ptr, long, fifth)
+{
+	int version, ret;
+
+	version = call >> 16; /* hack for backward compatibility */
+	call &= 0xffff;
+
+	switch (call) {
+	case SEMOP:
+		return sys_semtimedop(first, (struct sembuf __user *)ptr,
+				      second, NULL);
+	case SEMTIMEDOP:
+		return sys_semtimedop(first, (struct sembuf __user *)ptr,
+				      second,
+				      (const struct timespec __user *)fifth);
+
+	case SEMGET:
+		return sys_semget(first, second, third);
+	case SEMCTL: {
+		union semun fourth;
+		if (!ptr)
+			return -EINVAL;
+		if (get_user(fourth.__pad, (void __user * __user *) ptr))
+			return -EFAULT;
+		return sys_semctl(first, second, third, fourth);
+	}
+
+	case MSGSND:
+		return sys_msgsnd(first, (struct msgbuf __user *) ptr,
+				  second, third);
+	case MSGRCV:
+		switch (version) {
+		case 0: {
+			struct ipc_kludge tmp;
+			if (!ptr)
+				return -EINVAL;
+
+			if (copy_from_user(&tmp,
+					   (struct ipc_kludge __user *) ptr,
+					   sizeof(tmp)))
+				return -EFAULT;
+			return sys_msgrcv(first, tmp.msgp, second,
+					   tmp.msgtyp, third);
+		}
+		default:
+			return sys_msgrcv(first,
+					   (struct msgbuf __user *) ptr,
+					   second, fifth, third);
+		}
+	case MSGGET:
+		return sys_msgget((key_t) first, second);
+	case MSGCTL:
+		return sys_msgctl(first, second, (struct msqid_ds __user *)ptr);
+
+	case SHMAT:
+		switch (version) {
+		default: {
+			unsigned long raddr;
+			ret = do_shmat(first, (char __user *)ptr,
+				       second, &raddr);
+			if (ret)
+				return ret;
+			return put_user(raddr, (unsigned long __user *) third);
+		}
+		case 1:
+			/*
+			 * This was the entry point for kernel-originating calls
+			 * from iBCS2 in 2.2 days.
+			 */
+			return -EINVAL;
+		}
+	case SHMDT:
+		return sys_shmdt((char __user *)ptr);
+	case SHMGET:
+		return sys_shmget(first, second, third);
+	case SHMCTL:
+		return sys_shmctl(first, second,
+				   (struct shmid_ds __user *) ptr);
+	default:
+		return -ENOSYS;
+	}
+}
+#endif
diff --git a/ipc/util.c b/ipc/util.c
index 79ce84e890f7..69a0cc13d966 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -124,8 +124,8 @@ void ipc_init_ids(struct ipc_ids *ids)
 	ids->seq = 0;
 	{
 		int seq_limit = INT_MAX/SEQ_MULTIPLIER;
-		if (seq_limit > USHORT_MAX)
-			ids->seq_max = USHORT_MAX;
+		if (seq_limit > USHRT_MAX)
+			ids->seq_max = USHRT_MAX;
 		 else
 		 	ids->seq_max = seq_limit;
 	}