diff --git a/block/ioprio.c b/block/ioprio.c index 8c46f672a0ba..32a456b45804 100644 --- a/block/ioprio.c +++ b/block/ioprio.c @@ -171,10 +171,31 @@ static int get_task_ioprio(struct task_struct *p) ret = security_task_getioprio(p); if (ret) goto out; - ret = IOPRIO_DEFAULT; + task_lock(p); + ret = __get_task_ioprio(p); + task_unlock(p); +out: + return ret; +} + +/* + * Return raw IO priority value as set by userspace. We use this for + * ioprio_get(pid, IOPRIO_WHO_PROCESS) so that we keep historical behavior and + * also so that userspace can distinguish unset IO priority (which just gets + * overriden based on task's nice value) from IO priority set to some value. + */ +static int get_task_raw_ioprio(struct task_struct *p) +{ + int ret; + + ret = security_task_getioprio(p); + if (ret) + goto out; task_lock(p); if (p->io_context) ret = p->io_context->ioprio; + else + ret = IOPRIO_DEFAULT; task_unlock(p); out: return ret; @@ -182,11 +203,6 @@ out: static int ioprio_best(unsigned short aprio, unsigned short bprio) { - if (!ioprio_valid(aprio)) - aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NORM); - if (!ioprio_valid(bprio)) - bprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NORM); - return min(aprio, bprio); } @@ -207,7 +223,7 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who) else p = find_task_by_vpid(who); if (p) - ret = get_task_ioprio(p); + ret = get_task_raw_ioprio(p); break; case IOPRIO_WHO_PGRP: if (!who)