From dfc428b656c4693a2334a8d9865b430beddb562a Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 3 Aug 2011 16:21:04 -0700 Subject: [PATCH] taskstats: add_del_listener() shouldn't use the wrong node 1. Commit 26c4caea9d69 "don't allow duplicate entries in listener mode" changed add_del_listener(REGISTER) so that "next_cpu:" can reuse the listener allocated for the previous cpu, this doesn't look exactly right even if minor. Change the code to kfree() in the already-registered case, this case is unlikely anyway so the extra kmalloc_node() shouldn't hurt but looke more correct and clean. 2. use the plain list_for_each_entry() instead of _safe() to scan listeners->list. 3. Remove the unneeded INIT_LIST_HEAD(&s->list), we are going to list_add(&s->list). Signed-off-by: Oleg Nesterov Reviewed-by: Vasiliy Kulikov Cc: Balbir Singh Reviewed-by: Jerome Marchand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/taskstats.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/kernel/taskstats.c b/kernel/taskstats.c index d1db2880d1cf..a09a54936f19 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -291,30 +291,28 @@ static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd) if (!cpumask_subset(mask, cpu_possible_mask)) return -EINVAL; - s = NULL; if (isadd == REGISTER) { for_each_cpu(cpu, mask) { - if (!s) - s = kmalloc_node(sizeof(struct listener), - GFP_KERNEL, cpu_to_node(cpu)); + s = kmalloc_node(sizeof(struct listener), + GFP_KERNEL, cpu_to_node(cpu)); if (!s) goto cleanup; + s->pid = pid; - INIT_LIST_HEAD(&s->list); s->valid = 1; listeners = &per_cpu(listener_array, cpu); down_write(&listeners->sem); - list_for_each_entry_safe(s2, tmp, &listeners->list, list) { + list_for_each_entry(s2, &listeners->list, list) { if (s2->pid == pid) - goto next_cpu; + goto exists; } list_add(&s->list, &listeners->list); s = NULL; -next_cpu: +exists: up_write(&listeners->sem); + kfree(s); /* nop if NULL */ } - kfree(s); return 0; } -- 2.34.1