X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fioprio.c;h=c7c0b28d7d2177c7c88d32f3f62856e97cfc7ff5;hb=80f506918fdaaca6b574ba931536a58ce015c7be;hp=0fd1089d7bf6cf00e6cdb0e72213af3a15c31359;hpb=fc46379daf90dce57bf765c81d3b39f55150aac2;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/ioprio.c b/fs/ioprio.c index 0fd1089..c7c0b28 100644 --- a/fs/ioprio.c +++ b/fs/ioprio.c @@ -1,7 +1,7 @@ /* * fs/ioprio.c * - * Copyright (C) 2004 Jens Axboe + * Copyright (C) 2004 Jens Axboe * * Helper functions for setting/querying io priorities of processes. The * system calls closely mimmick getpriority/setpriority, see the man page for @@ -25,41 +25,60 @@ #include #include #include +#include -static int set_task_ioprio(struct task_struct *task, int ioprio) +int set_task_ioprio(struct task_struct *task, int ioprio) { int err; struct io_context *ioc; + const struct cred *cred = current_cred(), *tcred; - if (task->uid != current->euid && - task->uid != current->uid && !capable(CAP_SYS_NICE)) + rcu_read_lock(); + tcred = __task_cred(task); + if (tcred->uid != cred->euid && + tcred->uid != cred->uid && !capable(CAP_SYS_NICE)) { + rcu_read_unlock(); return -EPERM; + } + rcu_read_unlock(); err = security_task_setioprio(task, ioprio); if (err) return err; task_lock(task); + do { + ioc = task->io_context; + /* see wmb() in current_io_context() */ + smp_read_barrier_depends(); + if (ioc) + break; - task->ioprio = ioprio; - - ioc = task->io_context; - /* see wmb() in current_io_context() */ - smp_read_barrier_depends(); + ioc = alloc_io_context(GFP_ATOMIC, -1); + if (!ioc) { + err = -ENOMEM; + break; + } + task->io_context = ioc; + } while (1); - if (ioc) + if (!err) { + ioc->ioprio = ioprio; ioc->ioprio_changed = 1; + } task_unlock(task); - return 0; + return err; } +EXPORT_SYMBOL_GPL(set_task_ioprio); -asmlinkage long sys_ioprio_set(int which, int who, int ioprio) +SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio) { int class = IOPRIO_PRIO_CLASS(ioprio); int data = IOPRIO_PRIO_DATA(ioprio); struct task_struct *p, *g; struct user_struct *user; + struct pid *pgrp; int ret; switch (class) { @@ -73,36 +92,45 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) break; case IOPRIO_CLASS_IDLE: - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; + break; + case IOPRIO_CLASS_NONE: + if (data) + return -EINVAL; break; default: return -EINVAL; } ret = -ESRCH; - read_lock_irq(&tasklist_lock); + /* + * We want IOPRIO_WHO_PGRP/IOPRIO_WHO_USER to be "atomic", + * so we can't use rcu_read_lock(). See re-copy of ->ioprio + * in copy_process(). + */ + read_lock(&tasklist_lock); switch (which) { case IOPRIO_WHO_PROCESS: if (!who) p = current; else - p = find_task_by_pid(who); + p = find_task_by_vpid(who); if (p) ret = set_task_ioprio(p, ioprio); break; case IOPRIO_WHO_PGRP: if (!who) - who = process_group(current); - do_each_task_pid(who, PIDTYPE_PGID, p) { + pgrp = task_pgrp(current); + else + pgrp = find_vpid(who); + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { ret = set_task_ioprio(p, ioprio); if (ret) break; - } while_each_task_pid(who, PIDTYPE_PGID, p); + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); break; case IOPRIO_WHO_USER: if (!who) - user = current->user; + user = current_user(); else user = find_user(who); @@ -110,7 +138,7 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) break; do_each_thread(g, p) { - if (p->uid != who) + if (__task_cred(p)->uid != who) continue; ret = set_task_ioprio(p, ioprio); if (ret) @@ -124,7 +152,7 @@ free_uid: ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; } @@ -135,7 +163,9 @@ static int get_task_ioprio(struct task_struct *p) ret = security_task_getioprio(p); if (ret) goto out; - ret = p->ioprio; + ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); + if (p->io_context) + ret = p->io_context->ioprio; out: return ret; } @@ -145,11 +175,6 @@ int ioprio_best(unsigned short aprio, unsigned short bprio) unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); - if (!ioprio_valid(aprio)) - return bprio; - if (!ioprio_valid(bprio)) - return aprio; - if (aclass == IOPRIO_CLASS_NONE) aclass = IOPRIO_CLASS_BE; if (bclass == IOPRIO_CLASS_NONE) @@ -163,27 +188,30 @@ int ioprio_best(unsigned short aprio, unsigned short bprio) return aprio; } -asmlinkage long sys_ioprio_get(int which, int who) +SYSCALL_DEFINE2(ioprio_get, int, which, int, who) { struct task_struct *g, *p; struct user_struct *user; + struct pid *pgrp; int ret = -ESRCH; int tmpio; - read_lock_irq(&tasklist_lock); + read_lock(&tasklist_lock); switch (which) { case IOPRIO_WHO_PROCESS: if (!who) p = current; else - p = find_task_by_pid(who); + p = find_task_by_vpid(who); if (p) ret = get_task_ioprio(p); break; case IOPRIO_WHO_PGRP: if (!who) - who = process_group(current); - do_each_task_pid(who, PIDTYPE_PGID, p) { + pgrp = task_pgrp(current); + else + pgrp = find_vpid(who); + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { tmpio = get_task_ioprio(p); if (tmpio < 0) continue; @@ -191,11 +219,11 @@ asmlinkage long sys_ioprio_get(int which, int who) ret = tmpio; else ret = ioprio_best(ret, tmpio); - } while_each_task_pid(who, PIDTYPE_PGID, p); + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); break; case IOPRIO_WHO_USER: if (!who) - user = current->user; + user = current_user(); else user = find_user(who); @@ -203,7 +231,7 @@ asmlinkage long sys_ioprio_get(int which, int who) break; do_each_thread(g, p) { - if (p->uid != user->uid) + if (__task_cred(p)->uid != user->uid) continue; tmpio = get_task_ioprio(p); if (tmpio < 0) @@ -221,7 +249,6 @@ asmlinkage long sys_ioprio_get(int which, int who) ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; } -