Quoting Oren Laadan (orenl@xxxxxxxxxxxxxxx):
> The field task->checkpoint_data was introduced to hold the saved
> mask of a task so that it could be restored last thing before a
> task returns to userspace.
>
> Given that we can piggyback on the existing task->saved_sigmask field,
> this patch drops the special checkpoint_data pointer.
>
> Signed-off-by: Oren Laadan <orenl@xxxxxxxxxxxxxxx>
Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
I love dropping tsk->checkpoint_data.
This doesn't address the possibility that we might need to actually
checkpoint the saved_sigmask instead of blocked in certain cases,
of course, I assume that would come in a later patch?
-serge
> ---
> checkpoint/process.c | 18 ++----------------
> checkpoint/signal.c | 4 ++--
> include/linux/checkpoint_types.h | 4 ----
> include/linux/sched.h | 1 -
> 4 files changed, 4 insertions(+), 23 deletions(-)
>
> diff --git a/checkpoint/process.c b/checkpoint/process.c
> index 94cd0c1..f917112 100644
> --- a/checkpoint/process.c
> +++ b/checkpoint/process.c
> @@ -858,11 +858,6 @@ int pre_restore_task(void)
> {
> sigset_t sigset;
>
> - /* task-specific restart data: freed from post_restore_task() */
> - current->checkpoint_data = kzalloc(sizeof(struct ckpt_data), GFP_KERNEL);
> - if (!current->checkpoint_data)
> - return -ENOMEM;
> -
> /*
> * Block task's signals to avoid interruptions due to signals,
> * say, from restored timers, file descriptors etc. Signals
> @@ -872,8 +867,7 @@ int pre_restore_task(void)
> * i/o notification may fail the restart if a signal occurs
> * before that task completed its restore. FIX ?
> */
> -
> - current->checkpoint_data->blocked = current->blocked;
> + current->saved_sigmask = current->blocked;
>
> sigfillset(&sigset);
> sigdelset(&sigset, SIGKILL);
> @@ -886,16 +880,8 @@ int pre_restore_task(void)
> /* finish up task restore */
> void post_restore_task(void)
> {
> - /* can happen if restart failed early */
> - if (!current->checkpoint_data)
> - return;
> -
> /* only now is it safe to unblock the restored task's signals */
> - sigprocmask(SIG_SETMASK, ¤t->checkpoint_data->blocked, NULL);
> -
> - /* task-specific restart data: allocated in pre_restore_task() */
> - kfree(current->checkpoint_data);
> - current->checkpoint_data = NULL;
> + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
> }
>
> /* read the entire state of the current task */
> diff --git a/checkpoint/signal.c b/checkpoint/signal.c
> index 609e924..d448278 100644
> --- a/checkpoint/signal.c
> +++ b/checkpoint/signal.c
> @@ -719,10 +719,10 @@ int restore_task_signal(struct ckpt_ctx *ctx)
>
> /*
> * Unblocking signals now may affect us in wait_task_sync().
> - * Instead, save blocked mask in current->checkpoint_data for
> + * Instead, save blocked mask in current->saved_sigmaks for
> * post_restore_task().
> */
> - current->checkpoint_data->blocked = blocked;
> + current->saved_sigmask = blocked;
>
> ckpt_hdr_put(ctx, h);
> return 0;
> diff --git a/include/linux/checkpoint_types.h b/include/linux/checkpoint_types.h
> index 51efd5a..5d5e00d 100644
> --- a/include/linux/checkpoint_types.h
> +++ b/include/linux/checkpoint_types.h
> @@ -29,10 +29,6 @@ struct ckpt_stats {
> int user_ns;
> };
>
> -struct ckpt_data {
> - sigset_t blocked;
> -};
> -
> struct ckpt_ctx {
> int crid; /* unique checkpoint id */
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 965b6c6..a70d7d1 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1584,7 +1584,6 @@ struct task_struct {
> #endif
> #ifdef CONFIG_CHECKPOINT
> struct ckpt_ctx *checkpoint_ctx;
> - struct ckpt_data *checkpoint_data;
> #endif
> };
>
> --
> 1.6.3.3
>
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