[patch -mm] update mq_notify to use a struct pid

message queues can signal a process waiting for a message.

this patch replaces the pid_t value with a struct pid to avoid pid wrap
around problems.

Signed-off-by: Cedric Le Goater <clg RemoveThis @fr.ibm.com>
Cc: Eric Biederman <ebiederm RemoveThis @xmission.com>
Cc: Andrew Morton <akpm RemoveThis @osdl.org>
Cc: containers RemoveThis @lists.osdl.org

---
ipc/mqueue.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)

Index: 2.6.18-rc6-mm1/ipc/mqueue.c
===================================================================
--- 2.6.18-rc6-mm1.orig/ipc/mqueue.c
+++ 2.6.18-rc6-mm1/ipc/mqueue.c
@@ -73,7 +73,7 @@ struct mqueue_inode_info {
struct mq_attr attr;

struct sigevent notify;
- pid_t notify_owner;
+ struct pid* notify_owner;
struct user_struct *user; /* user who created, for accounting */
struct sock *notify_sock;
struct sk_buff *notify_cookie;
@@ -134,7 +134,7 @@ static struct inode *mqueue_get_inode(st
INIT_LIST_HEAD(&info->e_wait_q[0].list);
INIT_LIST_HEAD(&info->e_wait_q[1].list);
info->messages = NULL;
- info->notify_owner = 0;
+ info->notify_owner = NULL;
info->qsize = 0;
info->user = NULL; /* set when all is ok */
memset(&info->attr, 0, sizeof(info->attr));
@@ -338,7 +338,7 @@ static ssize_t mqueue_read_file(struct f
(info->notify_owner &&
info->notify.sigev_notify == SIGEV_SIGNAL) ?
info->notify.sigev_signo : 0,
- info->notify_owner);
+ pid_nr(info->notify_owner));
spin_unlock(&info->lock);
buffer[sizeof(buffer)-1] = '\0';
slen = strlen(buffer)+1;
@@ -363,7 +363,7 @@ static int mqueue_flush_file(struct file
struct mqueue_inode_info *info = MQUEUE_I(filp->f_dentry->d_inode);

spin_lock(&info->lock);
- if (current->tgid == info->notify_owner)
+ if (task_tgid(current) == info->notify_owner)
remove_notification(info);

spin_unlock(&info->lock);
@@ -518,8 +518,8 @@ static void __do_notify(struct mqueue_in
sig_i.si_pid = current->tgid;
sig_i.si_uid = current->uid;

- kill_proc_info(info->notify.sigev_signo,
- &sig_i, info->notify_owner);
+ kill_pid_info(info->notify.sigev_signo,
+ &sig_i, info->notify_owner);
break;
case SIGEV_THREAD:
set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
@@ -528,7 +528,8 @@ static void __do_notify(struct mqueue_in
break;
}
/* after notification unregisters process */
- info->notify_owner = 0;
+ put_pid(info->notify_owner);
+ info->notify_owner = NULL;
}
wake_up(&info->wait_q);
}
@@ -566,12 +567,13 @@ static long prepare_timeout(const struct

static void remove_notification(struct mqueue_inode_info *info)
{
- if (info->notify_owner != 0 &&
+ if (info->notify_owner != NULL &&
info->notify.sigev_notify == SIGEV_THREAD) {
set_cookie(info->notify_cookie, NOTIFY_REMOVED);
netlink_sendskb(info->notify_sock, info->notify_cookie, 0);
}
- info->notify_owner = 0;
+ put_pid(info->notify_owner);
+ info->notify_owner = NULL;
}

static int mq_attr_ok(struct mq_attr *attr)
@@ -1062,11 +1064,11 @@ retry:
ret = 0;
spin_lock(&info->lock);
if (u_notification == NULL) {
- if (info->notify_owner == current->tgid) {
+ if (info->notify_owner == task_tgid(current)) {
remove_notification(info);
inode->i_atime = inode->i_ctime = CURRENT_TIME;
}
- } else if (info->notify_owner != 0) {
+ } else if (info->notify_owner != NULL) {
ret = -EBUSY;
} else {
switch (notification.sigev_notify) {
@@ -1086,7 +1088,8 @@ retry:
info->notify.sigev_notify = SIGEV_SIGNAL;
break;
}
- info->notify_owner = current->tgid;
+
+ info->notify_owner = get_pid(task_tgid(current));
inode->i_atime = inode->i_ctime = CURRENT_TIME;
}
spin_unlock(&info->lock);
-
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Cedric Le Goater <clg.DeleteThis@fr.ibm.com> writes:

> message queues can signal a process waiting for a message.
>
> this patch replaces the pid_t value with a struct pid to avoid pid wrap
> around problems.
>
> Signed-off-by: Cedric Le Goater <clg.DeleteThis@fr.ibm.com>
> Cc: Eric Biederman <ebiederm.DeleteThis@xmission.com>
> Cc: Andrew Morton <akpm.DeleteThis@osdl.org>
> Cc: containers.DeleteThis@lists.osdl.org

Signed-off-by: Eric Biederman <ebiederm.DeleteThis@xmission.com>

I was just about to send out this patch in a couple more hours.
So expect the fact we wrote the same code is a good sign


Eric
-
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