Commit 2d70b68d authored by Ken Chen's avatar Ken Chen Committed by Linus Torvalds
Browse files

fix setpriority(PRIO_PGRP) thread iterator breakage 



When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP
process, only the task leader of the process is affected, all other
sibling LWP threads didn't receive the setting.  The problem was that the
iterator used in sys_setpriority() only iteartes over one task for each
process, ignoring all other sibling thread.

Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk
each thread of a process.  Convert 4 call sites in {set/get}priority and
ioprio_{set/get}.

Signed-off-by: default avatarKen Chen <kenchen@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 141d87e7

fs/ioprio.c

+4 −4
Original line number Diff line number Diff line
@@ -115,11 +115,11 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) 
				pgrp = task_pgrp(current);

			else

				pgrp = find_vpid(who);

			do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {

				ret = set_task_ioprio(p, ioprio);

				if (ret)

					break;

			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);

			break;

		case IOPRIO_WHO_USER:

			if (!who)
@@ -204,7 +204,7 @@ asmlinkage long sys_ioprio_get(int which, int who) 
				pgrp = task_pgrp(current);

			else

				pgrp = find_vpid(who);

			do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {

				tmpio = get_task_ioprio(p);

				if (tmpio < 0)

					continue;
@@ -212,7 +212,7 @@ asmlinkage long sys_ioprio_get(int which, int who) 
					ret = tmpio;

				else

					ret = ioprio_best(ret, tmpio);

			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);

			break;

		case IOPRIO_WHO_USER:

			if (!who)

include/linux/pid.h

+9 −0
Original line number Diff line number Diff line
@@ -161,4 +161,13 @@ pid_t pid_vnr(struct pid *pid); 
			}						\

	} while (0)



#define do_each_pid_thread(pid, type, task)				\

	do_each_pid_task(pid, type, task) {				\

		struct task_struct *tg___ = task;			\

		do {



#define while_each_pid_thread(pid, type, task)				\

		} while_each_thread(tg___, task);			\

		task = tg___;						\

	} while_each_pid_task(pid, type, task)

#endif /* _LINUX_PID_H */

kernel/sys.c

+4 −4
Original line number Diff line number Diff line
@@ -169,9 +169,9 @@ asmlinkage long sys_setpriority(int which, int who, int niceval) 
				pgrp = find_vpid(who);

			else

				pgrp = task_pgrp(current);

			do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {

				error = set_one_prio(p, niceval, error);

			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);

			break;

		case PRIO_USER:

			user = current->user;
@@ -229,11 +229,11 @@ asmlinkage long sys_getpriority(int which, int who) 
				pgrp = find_vpid(who);

			else

				pgrp = task_pgrp(current);

			do_each_pid_task(pgrp, PIDTYPE_PGID, p) {

			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {

				niceval = 20 - task_nice(p);

				if (niceval > retval)

					retval = niceval;

			} while_each_pid_task(pgrp, PIDTYPE_PGID, p);

			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);

			break;

		case PRIO_USER:

			user = current->user;

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