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0d167518e0
Merge block/IO core bits from Jens Axboe: "This is a bit bigger on the core side than usual, but that is purely because we decided to hold off on parts of Tejun's submission on 3.4 to give it a bit more time to simmer. As a consequence, it's seen a long cycle in for-next. It contains: - Bug fix from Dan, wrong locking type. - Relax splice gifting restriction from Eric. - A ton of updates from Tejun, primarily for blkcg. This improves the code a lot, making the API nicer and cleaner, and also includes fixes for how we handle and tie policies and re-activate on switches. The changes also include generic bug fixes. - A simple fix from Vivek, along with a fix for doing proper delayed allocation of the blkcg stats." Fix up annoying conflict just due to different merge resolution in Documentation/feature-removal-schedule.txt * 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits) blkcg: tg_stats_alloc_lock is an irq lock vmsplice: relax alignement requirements for SPLICE_F_GIFT blkcg: use radix tree to index blkgs from blkcg blkcg: fix blkcg->css ref leak in __blkg_lookup_create() block: fix elvpriv allocation failure handling block: collapse blk_alloc_request() into get_request() blkcg: collapse blkcg_policy_ops into blkcg_policy blkcg: embed struct blkg_policy_data in policy specific data blkcg: mass rename of blkcg API blkcg: style cleanups for blk-cgroup.h blkcg: remove blkio_group->path[] blkcg: blkg_rwstat_read() was missing inline blkcg: shoot down blkgs if all policies are deactivated blkcg: drop stuff unused after per-queue policy activation update blkcg: implement per-queue policy activation blkcg: add request_queue->root_blkg blkcg: make request_queue bypassing on allocation blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing blkcg: make blkg_conf_prep() take @pol and return with queue lock held blkcg: remove static policy ID enums ...
242 lines
5.0 KiB
C
242 lines
5.0 KiB
C
/*
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* fs/ioprio.c
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*
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* Copyright (C) 2004 Jens Axboe <axboe@kernel.dk>
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*
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* Helper functions for setting/querying io priorities of processes. The
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* system calls closely mimmick getpriority/setpriority, see the man page for
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* those. The prio argument is a composite of prio class and prio data, where
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* the data argument has meaning within that class. The standard scheduling
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* classes have 8 distinct prio levels, with 0 being the highest prio and 7
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* being the lowest.
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*
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* IOW, setting BE scheduling class with prio 2 is done ala:
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*
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* unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
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*
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* ioprio_set(PRIO_PROCESS, pid, prio);
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*
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* See also Documentation/block/ioprio.txt
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*
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*/
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#include <linux/gfp.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/ioprio.h>
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#include <linux/blkdev.h>
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#include <linux/capability.h>
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#include <linux/syscalls.h>
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#include <linux/security.h>
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#include <linux/pid_namespace.h>
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int set_task_ioprio(struct task_struct *task, int ioprio)
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{
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int err;
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struct io_context *ioc;
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const struct cred *cred = current_cred(), *tcred;
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rcu_read_lock();
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tcred = __task_cred(task);
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if (!uid_eq(tcred->uid, cred->euid) &&
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!uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) {
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rcu_read_unlock();
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return -EPERM;
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}
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rcu_read_unlock();
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err = security_task_setioprio(task, ioprio);
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if (err)
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return err;
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ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
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if (ioc) {
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ioc->ioprio = ioprio;
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put_io_context(ioc);
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(set_task_ioprio);
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SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
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{
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int class = IOPRIO_PRIO_CLASS(ioprio);
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int data = IOPRIO_PRIO_DATA(ioprio);
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struct task_struct *p, *g;
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struct user_struct *user;
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struct pid *pgrp;
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kuid_t uid;
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int ret;
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switch (class) {
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case IOPRIO_CLASS_RT:
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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/* fall through, rt has prio field too */
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case IOPRIO_CLASS_BE:
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if (data >= IOPRIO_BE_NR || data < 0)
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return -EINVAL;
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break;
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case IOPRIO_CLASS_IDLE:
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break;
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case IOPRIO_CLASS_NONE:
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if (data)
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return -EINVAL;
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break;
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default:
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return -EINVAL;
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}
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ret = -ESRCH;
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rcu_read_lock();
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switch (which) {
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case IOPRIO_WHO_PROCESS:
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if (!who)
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p = current;
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else
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p = find_task_by_vpid(who);
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if (p)
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ret = set_task_ioprio(p, ioprio);
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break;
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case IOPRIO_WHO_PGRP:
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if (!who)
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pgrp = task_pgrp(current);
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else
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pgrp = find_vpid(who);
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do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
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ret = set_task_ioprio(p, ioprio);
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if (ret)
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break;
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} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
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break;
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case IOPRIO_WHO_USER:
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uid = make_kuid(current_user_ns(), who);
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if (!uid_valid(uid))
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break;
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if (!who)
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user = current_user();
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else
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user = find_user(uid);
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if (!user)
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break;
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do_each_thread(g, p) {
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if (!uid_eq(task_uid(p), uid))
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continue;
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ret = set_task_ioprio(p, ioprio);
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if (ret)
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goto free_uid;
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} while_each_thread(g, p);
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free_uid:
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if (who)
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free_uid(user);
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break;
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default:
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ret = -EINVAL;
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}
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rcu_read_unlock();
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return ret;
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}
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static int get_task_ioprio(struct task_struct *p)
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{
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int ret;
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ret = security_task_getioprio(p);
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if (ret)
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goto out;
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ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
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if (p->io_context)
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ret = p->io_context->ioprio;
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out:
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return ret;
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}
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int ioprio_best(unsigned short aprio, unsigned short bprio)
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{
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unsigned short aclass = IOPRIO_PRIO_CLASS(aprio);
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unsigned short bclass = IOPRIO_PRIO_CLASS(bprio);
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if (aclass == IOPRIO_CLASS_NONE)
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aclass = IOPRIO_CLASS_BE;
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if (bclass == IOPRIO_CLASS_NONE)
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bclass = IOPRIO_CLASS_BE;
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if (aclass == bclass)
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return min(aprio, bprio);
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if (aclass > bclass)
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return bprio;
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else
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return aprio;
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}
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SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
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{
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struct task_struct *g, *p;
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struct user_struct *user;
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struct pid *pgrp;
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kuid_t uid;
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int ret = -ESRCH;
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int tmpio;
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rcu_read_lock();
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switch (which) {
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case IOPRIO_WHO_PROCESS:
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if (!who)
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p = current;
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else
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p = find_task_by_vpid(who);
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if (p)
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ret = get_task_ioprio(p);
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break;
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case IOPRIO_WHO_PGRP:
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if (!who)
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pgrp = task_pgrp(current);
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else
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pgrp = find_vpid(who);
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do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
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tmpio = get_task_ioprio(p);
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if (tmpio < 0)
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continue;
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if (ret == -ESRCH)
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ret = tmpio;
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else
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ret = ioprio_best(ret, tmpio);
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} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
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break;
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case IOPRIO_WHO_USER:
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uid = make_kuid(current_user_ns(), who);
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if (!who)
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user = current_user();
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else
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user = find_user(uid);
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if (!user)
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break;
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do_each_thread(g, p) {
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if (!uid_eq(task_uid(p), user->uid))
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continue;
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tmpio = get_task_ioprio(p);
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if (tmpio < 0)
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continue;
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if (ret == -ESRCH)
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ret = tmpio;
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else
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ret = ioprio_best(ret, tmpio);
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} while_each_thread(g, p);
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if (who)
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free_uid(user);
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break;
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default:
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ret = -EINVAL;
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}
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rcu_read_unlock();
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return ret;
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}
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