Change set_special_pids() to work with struct pid, not pid_t from global name
space. This again speedups and imho cleanups the code.
Signed-off-by: Oleg Nesterov <[email protected]>
--- PT/include/linux/sched.h~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
+++ PT/include/linux/sched.h 2007-11-26 16:47:35.000000000 +0300
@@ -1568,7 +1568,7 @@ extern struct task_struct *find_task_by_
extern struct task_struct *find_task_by_pid_ns(pid_t nr,
struct pid_namespace *ns);
-extern void __set_special_pids(pid_t session, pid_t pgrp);
+extern void __set_special_pids(struct pid *pid);
/* per-UID process charging. */
extern struct user_struct * alloc_uid(struct user_namespace *, uid_t);
--- PT/kernel/exit.c~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
+++ PT/kernel/exit.c 2007-11-26 16:47:35.000000000 +0300
@@ -295,26 +295,27 @@ static void reparent_to_kthreadd(void)
switch_uid(INIT_USER);
}
-void __set_special_pids(pid_t session, pid_t pgrp)
+void __set_special_pids(struct pid *pid)
{
struct task_struct *curr = current->group_leader;
+ pid_t nr = pid_nr(pid);
- if (task_session_nr(curr) != session) {
+ if (task_session(curr) != pid) {
detach_pid(curr, PIDTYPE_SID);
- set_task_session(curr, session);
- attach_pid(curr, PIDTYPE_SID, find_pid(session));
+ attach_pid(curr, PIDTYPE_SID, pid);
+ set_task_session(curr, nr);
}
- if (task_pgrp_nr(curr) != pgrp) {
+ if (task_pgrp(curr) != pid) {
detach_pid(curr, PIDTYPE_PGID);
- set_task_pgrp(curr, pgrp);
- attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp));
+ attach_pid(curr, PIDTYPE_PGID, pid);
+ set_task_pgrp(curr, nr);
}
}
-static void set_special_pids(pid_t session, pid_t pgrp)
+static void set_special_pids(struct pid *pid)
{
write_lock_irq(&tasklist_lock);
- __set_special_pids(session, pgrp);
+ __set_special_pids(pid);
write_unlock_irq(&tasklist_lock);
}
@@ -385,7 +386,11 @@ void daemonize(const char *name, ...)
*/
current->flags |= PF_NOFREEZE;
- set_special_pids(1, 1);
+ if (current->nsproxy != &init_nsproxy) {
+ get_nsproxy(&init_nsproxy);
+ switch_task_namespaces(current, &init_nsproxy);
+ }
+ set_special_pids(find_pid(1));
proc_clear_tty(current);
/* Block and flush all signals */
@@ -400,11 +405,6 @@ void daemonize(const char *name, ...)
current->fs = fs;
atomic_inc(&fs->count);
- if (current->nsproxy != init_task.nsproxy) {
- get_nsproxy(init_task.nsproxy);
- switch_task_namespaces(current, init_task.nsproxy);
- }
-
exit_files(current);
current->files = init_task.files;
atomic_inc(¤t->files->count);
--- PT/kernel/sys.c~2_set_special_pids 2007-11-26 16:10:43.000000000 +0300
+++ PT/kernel/sys.c 2007-11-26 16:48:02.000000000 +0300
@@ -1065,7 +1065,7 @@ asmlinkage long sys_setsid(void)
goto out;
group_leader->signal->leader = 1;
- __set_special_pids(pid_nr(sid), pid_nr(sid));
+ __set_special_pids(sid);
spin_lock(&group_leader->sighand->siglock);
group_leader->signal->tty = NULL;
--- PT/init/main.c~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
+++ PT/init/main.c 2007-11-26 16:56:24.000000000 +0300
@@ -829,7 +829,7 @@ static int __init kernel_init(void * unu
*/
init_pid_ns.child_reaper = current;
- __set_special_pids(1, 1);
+ __set_special_pids(task_pid(current));
cad_pid = task_pid(current);
smp_prepare_cpus(max_cpus);
Oleg Nesterov wrote:
> Change set_special_pids() to work with struct pid, not pid_t from global name
> space. This again speedups and imho cleanups the code.
>
> Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
> --- PT/include/linux/sched.h~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
> +++ PT/include/linux/sched.h 2007-11-26 16:47:35.000000000 +0300
> @@ -1568,7 +1568,7 @@ extern struct task_struct *find_task_by_
> extern struct task_struct *find_task_by_pid_ns(pid_t nr,
> struct pid_namespace *ns);
>
> -extern void __set_special_pids(pid_t session, pid_t pgrp);
> +extern void __set_special_pids(struct pid *pid);
>
> /* per-UID process charging. */
> extern struct user_struct * alloc_uid(struct user_namespace *, uid_t);
> --- PT/kernel/exit.c~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
> +++ PT/kernel/exit.c 2007-11-26 16:47:35.000000000 +0300
> @@ -295,26 +295,27 @@ static void reparent_to_kthreadd(void)
> switch_uid(INIT_USER);
> }
>
> -void __set_special_pids(pid_t session, pid_t pgrp)
> +void __set_special_pids(struct pid *pid)
> {
> struct task_struct *curr = current->group_leader;
> + pid_t nr = pid_nr(pid);
>
> - if (task_session_nr(curr) != session) {
> + if (task_session(curr) != pid) {
> detach_pid(curr, PIDTYPE_SID);
> - set_task_session(curr, session);
> - attach_pid(curr, PIDTYPE_SID, find_pid(session));
> + attach_pid(curr, PIDTYPE_SID, pid);
> + set_task_session(curr, nr);
> }
> - if (task_pgrp_nr(curr) != pgrp) {
> + if (task_pgrp(curr) != pid) {
> detach_pid(curr, PIDTYPE_PGID);
> - set_task_pgrp(curr, pgrp);
> - attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp));
> + attach_pid(curr, PIDTYPE_PGID, pid);
> + set_task_pgrp(curr, nr);
> }
> }
>
> -static void set_special_pids(pid_t session, pid_t pgrp)
> +static void set_special_pids(struct pid *pid)
> {
> write_lock_irq(&tasklist_lock);
> - __set_special_pids(session, pgrp);
> + __set_special_pids(pid);
> write_unlock_irq(&tasklist_lock);
> }
>
> @@ -385,7 +386,11 @@ void daemonize(const char *name, ...)
> */
> current->flags |= PF_NOFREEZE;
>
> - set_special_pids(1, 1);
> + if (current->nsproxy != &init_nsproxy) {
> + get_nsproxy(&init_nsproxy);
> + switch_task_namespaces(current, &init_nsproxy);
> + }
> + set_special_pids(find_pid(1));
> proc_clear_tty(current);
>
> /* Block and flush all signals */
> @@ -400,11 +405,6 @@ void daemonize(const char *name, ...)
> current->fs = fs;
> atomic_inc(&fs->count);
>
> - if (current->nsproxy != init_task.nsproxy) {
> - get_nsproxy(init_task.nsproxy);
> - switch_task_namespaces(current, init_task.nsproxy);
> - }
> -
> exit_files(current);
> current->files = init_task.files;
> atomic_inc(¤t->files->count);
> --- PT/kernel/sys.c~2_set_special_pids 2007-11-26 16:10:43.000000000 +0300
> +++ PT/kernel/sys.c 2007-11-26 16:48:02.000000000 +0300
> @@ -1065,7 +1065,7 @@ asmlinkage long sys_setsid(void)
> goto out;
>
> group_leader->signal->leader = 1;
> - __set_special_pids(pid_nr(sid), pid_nr(sid));
> + __set_special_pids(sid);
>
> spin_lock(&group_leader->sighand->siglock);
> group_leader->signal->tty = NULL;
> --- PT/init/main.c~2_set_special_pids 2007-11-26 15:52:15.000000000 +0300
> +++ PT/init/main.c 2007-11-26 16:56:24.000000000 +0300
> @@ -829,7 +829,7 @@ static int __init kernel_init(void * unu
> */
> init_pid_ns.child_reaper = current;
>
> - __set_special_pids(1, 1);
> + __set_special_pids(task_pid(current));
> cad_pid = task_pid(current);
>
> smp_prepare_cpus(max_cpus);
>
>
Oleg Nesterov <[email protected]> writes:
> Change set_special_pids() to work with struct pid, not pid_t from global name
> space. This again speedups and imho cleanups the code.
>
> Signed-off-by: Oleg Nesterov <[email protected]>
Overall I like it, and the version I keep meaning to send missed
the fact we only need a single argument.
> -static void set_special_pids(pid_t session, pid_t pgrp)
> +static void set_special_pids(struct pid *pid)
> {
> write_lock_irq(&tasklist_lock);
> - __set_special_pids(session, pgrp);
> + __set_special_pids(pid);
> write_unlock_irq(&tasklist_lock);
> }
>
> @@ -385,7 +386,11 @@ void daemonize(const char *name, ...)
> */
> current->flags |= PF_NOFREEZE;
>
> - set_special_pids(1, 1);
> + if (current->nsproxy != &init_nsproxy) {
> + get_nsproxy(&init_nsproxy);
> + switch_task_namespaces(current, &init_nsproxy);
> + }
Is there a reason for moving this hunk of code?
I don't see one as set_special_pids does everything with either
struct pid or global pid values. And attach_pid and detach_pid
don't care.
Eric
On 11/26, Eric W. Biederman wrote:
>
> Oleg Nesterov <[email protected]> writes:
>
> > - set_special_pids(1, 1);
> > + if (current->nsproxy != &init_nsproxy) {
> > + get_nsproxy(&init_nsproxy);
> > + switch_task_namespaces(current, &init_nsproxy);
> > + }
>
> Is there a reason for moving this hunk of code?
>
> I don't see one as set_special_pids does everything with either
> struct pid or global pid values. And attach_pid and detach_pid
> don't care.
No particular reason, except "keep related code together".
There was another minor reason. Without the next patch we are doing find_pid(1).
This is correct, we scan the global namespace, but still it looks a bit tidier
to switch namespace first, so we could use find_vpid() in unlikely case we need
it.
Oleg.
Oleg Nesterov <[email protected]> writes:
> On 11/26, Eric W. Biederman wrote:
>>
>> Oleg Nesterov <[email protected]> writes:
>>
>> > - set_special_pids(1, 1);
>> > + if (current->nsproxy != &init_nsproxy) {
>> > + get_nsproxy(&init_nsproxy);
>> > + switch_task_namespaces(current, &init_nsproxy);
>> > + }
>>
>> Is there a reason for moving this hunk of code?
>>
>> I don't see one as set_special_pids does everything with either
>> struct pid or global pid values. And attach_pid and detach_pid
>> don't care.
>
> No particular reason, except "keep related code together".
>
> There was another minor reason. Without the next patch we are doing find_pid(1).
> This is correct, we scan the global namespace, but still it looks a bit tidier
> to switch namespace first, so we could use find_vpid() in unlikely case we need
> it.
True. I just pointed it out because it seemed an unnecessary chunk.
Regardless it is harmless either way.
Acked-by: "Eric W. Biederman" <[email protected]>
Eric