X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fioprio.c;h=c4a1c3c65aac35ba999a4739fb3ed6549b5e1b75;hb=32c9874759651b69e496f89ec9e5e6702f67ffca;hp=4bf1c6365a19d2ce3d9ae52da457026792528f40;hpb=9abdc4cd8a81a3c29e051eb12963757ac60bd440;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/ioprio.c b/fs/ioprio.c index 4bf1c63..c4a1c3c 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 @@ -22,26 +22,47 @@ #include #include #include +#include #include +#include +#include static int set_task_ioprio(struct task_struct *task, int ioprio) { + int err; struct io_context *ioc; if (task->uid != current->euid && task->uid != current->uid && !capable(CAP_SYS_NICE)) return -EPERM; + 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 = alloc_io_context(GFP_ATOMIC, -1); + if (!ioc) { + err = -ENOMEM; + break; + } + task->io_context = ioc; + } while (1); - ioc = task->io_context; - if (ioc && ioc->set_ioprio) - ioc->set_ioprio(ioc, ioprio); + if (!err) { + ioc->ioprio = ioprio; + ioc->ioprio_changed = 1; + } task_unlock(task); - return 0; + return err; } asmlinkage long sys_ioprio_set(int which, int who, int ioprio) @@ -50,6 +71,7 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) int data = IOPRIO_PRIO_DATA(ioprio); struct task_struct *p, *g; struct user_struct *user; + struct pid *pgrp; int ret; switch (class) { @@ -63,32 +85,41 @@ 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_task(pgrp, PIDTYPE_PGID, p) { ret = set_task_ioprio(p, ioprio); if (ret) break; - } while_each_task_pid(who, PIDTYPE_PGID, p); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); break; case IOPRIO_WHO_USER: if (!who) @@ -104,9 +135,9 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) continue; ret = set_task_ioprio(p, ioprio); if (ret) - break; + goto free_uid; } while_each_thread(g, p); - +free_uid: if (who) free_uid(user); break; @@ -114,35 +145,74 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio) ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; } +static int get_task_ioprio(struct task_struct *p) +{ + int ret; + + ret = security_task_getioprio(p); + if (ret) + goto out; + ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM); + if (p->io_context) + ret = p->io_context->ioprio; +out: + return ret; +} + +int ioprio_best(unsigned short aprio, unsigned short bprio) +{ + unsigned short aclass = IOPRIO_PRIO_CLASS(aprio); + unsigned short bclass = IOPRIO_PRIO_CLASS(bprio); + + if (aclass == IOPRIO_CLASS_NONE) + aclass = IOPRIO_CLASS_BE; + if (bclass == IOPRIO_CLASS_NONE) + bclass = IOPRIO_CLASS_BE; + + if (aclass == bclass) + return min(aprio, bprio); + if (aclass > bclass) + return bprio; + else + return aprio; +} + asmlinkage long sys_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 = p->ioprio; + 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_task(pgrp, PIDTYPE_PGID, p) { + tmpio = get_task_ioprio(p); + if (tmpio < 0) + continue; if (ret == -ESRCH) - ret = p->ioprio; + ret = tmpio; else - ret = ioprio_best(ret, p->ioprio); - } while_each_task_pid(who, PIDTYPE_PGID, p); + ret = ioprio_best(ret, tmpio); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); break; case IOPRIO_WHO_USER: if (!who) @@ -156,10 +226,13 @@ asmlinkage long sys_ioprio_get(int which, int who) do_each_thread(g, p) { if (p->uid != user->uid) continue; + tmpio = get_task_ioprio(p); + if (tmpio < 0) + continue; if (ret == -ESRCH) - ret = p->ioprio; + ret = tmpio; else - ret = ioprio_best(ret, p->ioprio); + ret = ioprio_best(ret, tmpio); } while_each_thread(g, p); if (who) @@ -169,7 +242,7 @@ asmlinkage long sys_ioprio_get(int which, int who) ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; }