[PATCH] copy_process: cosmetic ->ioprio tweak (5b160f5e) · Commits · 戴 / test

copy_process: // holds tasklist_lock + ->siglock /* * inherit ioprio */ p->ioprio = current->ioprio; Why? ->ioprio was already copied in dup_task_struct(). I guess this is needed to ensure that the child can't escape sys_ioprio_set(IOPRIO_WHO_{PGRP,USER}), yes? In that case we don't need ->siglock held, and the comment should be updated. Signed-off-by:

Oleg Nesterov <oleg@tv-sign.ru> Cc: Jens Axboe <axboe@suse.de> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

kernel/fork.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -1150,7 +1150,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,

		/* Our parent execution domain becomes current domain
		These must match for thread signalling to apply */

		p->parent_exec_id = p->self_exec_id;

		/* ok, now we should be set up.. */
		@@ -1173,6 +1172,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
		/* Need tasklist lock for parent etc handling! */
		write_lock_irq(&tasklist_lock);

		/* for sys_ioprio_set(IOPRIO_WHO_PGRP) */
		p->ioprio = current->ioprio;

		/*
		* The task hasn't been attached yet, so its cpus_allowed mask will
		* not be changed, nor will its assigned CPU.
		@@ -1232,11 +1234,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
		}
		}

		/*
		* inherit ioprio
		*/
		p->ioprio = current->ioprio;

		if (likely(p->pid)) {
		add_parent(p);
		if (unlikely(p->ptrace & PT_PTRACED))

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