Re: [PATCH 1/5] c/r: introduce ckpt_task_vnr(), ckpt_pid_vnr()

[Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>]

Hmmm.. the cover post did not make it :(

This patch-set changes the way pids are handled in c/r - instead
of simple pid numbers, we now treat them as proper shared objects.

The patch applies on top of the most recent branch 'ckpt-v23-rc1' 
of c/r (for 2.6.37 kernel).

Thanks,

Oren.

On 01/26/2011 11:10 AM, Oren Laadan wrote:
> This helpoer is Useful to get the pid from the root task's (checkpoint
> or restart) point of view.
> 
> Signed-off-by: Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
> ---
>  include/linux/checkpoint.h     |   10 +++++++++-
>  kernel/checkpoint/checkpoint.c |    5 +++--
>  kernel/checkpoint/restart.c    |    6 ++----
>  kernel/signal.c                |    2 +-
>  4 files changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
> index c015106..fe61edb 100644
> --- a/include/linux/checkpoint.h
> +++ b/include/linux/checkpoint.h
> @@ -110,8 +110,16 @@ extern int checkpoint_dump_page(struct ckpt_ctx *ctx, struct page *page);
>  extern int restore_read_page(struct ckpt_ctx *ctx, struct page *page);
>  
>  /* pids */
> -extern pid_t ckpt_pid_nr(struct ckpt_ctx *ctx, struct pid *pid);
>  extern struct pid *_ckpt_find_pgrp(struct ckpt_ctx *ctx, pid_t pgid);
> +static inline pid_t ckpt_task_vnr(struct ckpt_ctx *ctx, struct task_struct *task)
> +{
> +	return task_pid_nr_ns(task, ctx->root_nsproxy->pid_ns);
> +}
> +static inline pid_t ckpt_pid_vnr(struct ckpt_ctx *ctx, struct pid *pid)
> +{
> +	return pid_nr_ns(pid, ctx->root_nsproxy->pid_ns);
> +}
> +extern int ckpt_lookup_pid(struct ckpt_ctx *ctx, struct pid *pid);
>  
>  /* defined in objhash.c and also used in security/security.c */
>  extern void lsm_string_free(struct kref *kref);
> diff --git a/kernel/checkpoint/checkpoint.c b/kernel/checkpoint/checkpoint.c
> index 0f46acf..7cd491b 100644
> --- a/kernel/checkpoint/checkpoint.c
> +++ b/kernel/checkpoint/checkpoint.c
> @@ -28,6 +28,7 @@
>  #include <linux/hrtimer.h>
>  #include <linux/deferqueue.h>
>  #include <linux/checkpoint.h>
> +#include <linux/flex_array.h>
>  #include <linux/pid_namespace.h>
>  
>  /* unique checkpoint identifier (FIXME: should be per-container ?) */
> @@ -243,10 +244,10 @@ static int may_checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
>  {
>  	struct task_struct *root = ctx->root_task;
>  	struct nsproxy *nsproxy;
> -	int ret = 0;
>  	struct pid_namespace *pidns;
> +	int ret = 0;
>  
> -	ckpt_debug("check %d\n", task_pid_nr_ns(t, ctx->root_nsproxy->pid_ns));
> +	ckpt_debug("check %d\n", ckpt_task_vnr(ctx, t));
>  
>  	if (t->exit_state == EXIT_DEAD) {
>  		_ckpt_err(ctx, -EBUSY, "%(T)Task state EXIT_DEAD\n");
> diff --git a/kernel/checkpoint/restart.c b/kernel/checkpoint/restart.c
> index 2eae499..e844568 100644
> --- a/kernel/checkpoint/restart.c
> +++ b/kernel/checkpoint/restart.c
> @@ -913,8 +913,7 @@ static int wait_task_active(struct ckpt_ctx *ctx)
>  
>  static int wait_task_sync(struct ckpt_ctx *ctx)
>  {
> -	ckpt_debug("pid %d syncing\n",
> -		task_pid_nr_ns(current, task_active_pid_ns(ctx->root_task)));
> +	ckpt_debug("pid %d syncing\n", ckpt_task_vnr(ctx, current));
>  	wait_event_interruptible(ctx->waitq, ckpt_test_complete(ctx));
>  	ckpt_debug("task sync done (errno %d)\n", ctx->errno);
>  	if (ckpt_test_error(ctx))
> @@ -1187,10 +1186,9 @@ static struct task_struct *choose_root_task(struct ckpt_ctx *ctx, pid_t pid)
>  
>  	read_lock(&tasklist_lock);
>  	list_for_each_entry(task, &current->children, sibling) {
> -		if (task_pid_nr_ns(task, ctx->coord_pidns) == pid) {
> +		if (task_pid_vnr(task) == pid) {
>  			get_task_struct(task);
>  			ctx->root_task = task;
> -			ctx->root_pid = pid;
>  			break;
>  		}
>  	}
> diff --git a/kernel/signal.c b/kernel/signal.c
> index b1e6a31..dca40be 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -3352,7 +3352,7 @@ static int restore_signal(struct ckpt_ctx *ctx)
>  			 * fail, so no need for explicit test
>  			 */
>  			ret = do_tiocspgrp(tty, tty_pair_get_tty(tty),
> -					   h->tty_pgrp);
> +					   pid_vnr(pgrp));
>  			if (ret < 0)
>  				goto out;
>  		}