Subject: Move alloc_pid call to copy_process From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx> Move alloc_pid() into copy_process(). This will keep all pid and pid namespace code together and simplify error handling when we support multiple pid namespaces. Changelog: - [Eric Biederman] Move the check of copy_process_type to alloc_pid()/ free_pid() and to avoid clutter in copy_process(). Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx> --- include/linux/pid.h | 7 ++++++- kernel/fork.c | 21 +++++++++++++-------- kernel/pid.c | 10 +++++++++- 3 files changed, 28 insertions(+), 10 deletions(-) Index: lx26-21-mm2/include/linux/pid.h =================================================================== --- lx26-21-mm2.orig/include/linux/pid.h 2007-05-22 16:59:40.000000000 -0700 +++ lx26-21-mm2/include/linux/pid.h 2007-05-22 17:06:48.000000000 -0700 @@ -3,6 +3,11 @@ #include <linux/rcupdate.h> +enum copy_process_type { + COPY_NON_IDLE_PROCESS, + COPY_IDLE_PROCESS, +}; + enum pid_type { PIDTYPE_PID, @@ -95,7 +100,7 @@ extern struct pid *FASTCALL(find_pid(int extern struct pid *find_get_pid(int nr); extern struct pid *find_ge_pid(int nr); -extern struct pid *alloc_pid(void); +extern struct pid *alloc_pid(enum copy_process_type); extern void FASTCALL(free_pid(struct pid *pid)); static inline pid_t pid_to_nr(struct pid *pid) Index: lx26-21-mm2/kernel/fork.c =================================================================== --- lx26-21-mm2.orig/kernel/fork.c 2007-05-22 16:59:41.000000000 -0700 +++ lx26-21-mm2/kernel/fork.c 2007-05-22 17:06:48.000000000 -0700 @@ -961,10 +961,11 @@ static struct task_struct *copy_process( unsigned long stack_size, int __user *parent_tidptr, int __user *child_tidptr, - struct pid *pid) + enum copy_process_type copy_src) { int retval; struct task_struct *p = NULL; + struct pid *pid; if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) return ERR_PTR(-EINVAL); @@ -1025,6 +1026,10 @@ static struct task_struct *copy_process( if (p->binfmt && !try_module_get(p->binfmt->module)) goto bad_fork_cleanup_put_domain; + pid = alloc_pid(copy_src); + if (!pid) + goto bad_fork_put_binfmt_module; + p->did_exec = 0; delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ copy_flags(clone_flags, p); @@ -1305,6 +1310,8 @@ bad_fork_cleanup_cpuset: #endif cpuset_exit(p); delayacct_tsk_free(p); + free_pid(pid); +bad_fork_put_binfmt_module: if (p->binfmt) module_put(p->binfmt->module); bad_fork_cleanup_put_domain: @@ -1331,7 +1338,7 @@ struct task_struct * __cpuinit fork_idle struct pt_regs regs; task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, - &init_struct_pid); + COPY_IDLE_PROCESS); if (!IS_ERR(task)) init_idle(task, cpu); @@ -1369,19 +1376,16 @@ long do_fork(unsigned long clone_flags, { struct task_struct *p; int trace = 0; - struct pid *pid = alloc_pid(); long nr; - if (!pid) - return -EAGAIN; - nr = pid->nr; if (unlikely(current->ptrace)) { trace = fork_traceflag (clone_flags); if (trace) clone_flags |= CLONE_PTRACE; } - p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid); + p = copy_process(clone_flags, stack_start, regs, stack_size, + parent_tidptr, child_tidptr, COPY_NON_IDLE_PROCESS); /* * Do this prior waking up the new thread - the thread pointer * might get invalid after that point, if the thread exits quickly. @@ -1389,6 +1393,8 @@ long do_fork(unsigned long clone_flags, if (!IS_ERR(p)) { struct completion vfork; + nr = pid_to_nr(task_pid(p)); + if (clone_flags & CLONE_VFORK) { p->vfork_done = &vfork; init_completion(&vfork); @@ -1422,7 +1428,6 @@ long do_fork(unsigned long clone_flags, } } } else { - free_pid(pid); nr = PTR_ERR(p); } return nr; Index: lx26-21-mm2/kernel/pid.c =================================================================== --- lx26-21-mm2.orig/kernel/pid.c 2007-05-22 16:59:46.000000000 -0700 +++ lx26-21-mm2/kernel/pid.c 2007-05-22 17:06:48.000000000 -0700 @@ -216,6 +216,10 @@ fastcall void free_pid(struct pid *pid) /* We can be called with write_lock_irq(&tasklist_lock) held */ unsigned long flags; + /* check this here to keep copy_process() cleaner */ + if (unlikely(pid == &init_struct_pid)) + return; + spin_lock_irqsave(&pidmap_lock, flags); hlist_del_rcu(&pid->pid_chain); spin_unlock_irqrestore(&pidmap_lock, flags); @@ -224,12 +228,16 @@ fastcall void free_pid(struct pid *pid) call_rcu(&pid->rcu, delayed_put_pid); } -struct pid *alloc_pid(void) +struct pid *alloc_pid(enum copy_process_type copy_src) { struct pid *pid; enum pid_type type; int nr = -1; + /* check this here to keep copy_process() cleaner */ + if (unlikely(copy_src == COPY_IDLE_PROCESS)) + return &init_struct_pid; + pid = kmem_cache_alloc(pid_cachep, GFP_KERNEL); if (!pid) goto out; _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers