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author | Eric W. Biederman <ebiederm@xmission.com> | 2007-02-12 08:52:56 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-12 17:48:31 (GMT) |
commit | 04a2e6a5cbf84e85fe86de0a18f6509b147e1d89 (patch) | |
tree | 67dd67d2c4c18e5c36654dfe569e3085bd262ba5 /kernel/exit.c | |
parent | 8d42db189ca99703f0f4f91c477cb54808c8eaaa (diff) | |
download | linux-fsl-qoriq-04a2e6a5cbf84e85fe86de0a18f6509b147e1d89.tar.xz |
[PATCH] pid: make session_of_pgrp use struct pid instead of pid_t
To properly implement a pid namespace I need to deal exclusively in terms of
struct pid, because pid_t values become ambiguous.
To this end session_of_pgrp is transformed to take and return a struct pid
pointer. To avoid the need to worry about reference counting I now require my
caller to hold the appropriate locks. Leaving callers repsonsible for
increasing the reference count if they need access to the result outside of
the locks.
Since session_of_pgrp currently only has one caller and that caller simply
uses only test the result for equality with another process group, the locking
change means I don't actually have to acquire the tasklist_lock at all.
tiocspgrp is also modified to take and release the lock. The logic there is a
little more complicated but nothing I won't need when I convert pgrp of a tty
to a struct pid pointer.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r-- | kernel/exit.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 14f1703..3ac6a7a 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -185,21 +185,19 @@ repeat: * This checks not only the pgrp, but falls back on the pid if no * satisfactory pgrp is found. I dunno - gdb doesn't work correctly * without this... + * + * The caller must hold rcu lock or the tasklist lock. */ -int session_of_pgrp(int pgrp) +struct pid *session_of_pgrp(struct pid *pgrp) { struct task_struct *p; - int sid = 0; - - read_lock(&tasklist_lock); + struct pid *sid = NULL; - p = find_task_by_pid_type(PIDTYPE_PGID, pgrp); + p = pid_task(pgrp, PIDTYPE_PGID); if (p == NULL) - p = find_task_by_pid(pgrp); + p = pid_task(pgrp, PIDTYPE_PID); if (p != NULL) - sid = process_session(p); - - read_unlock(&tasklist_lock); + sid = task_session(p); return sid; } |