Re: [PATCH] lib/vsprintf: add %pT[C012] format specifier

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Pavel Machek wrote:
> > + * Please use this wrapper function which will be updated in the future to read
> > + * @tsk->comm in a consistent way.
> > + */
> > +static inline int commcmp(const struct task_struct *tsk, const char *comm)
> > +{
> > +	return strcmp(tsk->comm, comm);
> > +}
> 
> Is this useful to something? Printing command name is
> useful. Comparing it...?
>

(a) Using tsk->comm for reducing duplicated printk() messages.

    if (strcmp(p->comm, last_comm)) {
        printk("hello\n");
        strcpy(last_comm, p->comm);
    }

(b) Using tsk->pid for reducing duplicated printk() messages.

    if (p->pid != last_pid) {
        printk("hello\n");
        last_pid = p->pid;
    }

(c) Using printk_ratelimit() for reducing printk() flooding.

    printk_ratelimit("hello\n");

(d) Using plain printk().

    printk("hello\n");

(e) Other purposes. (e.g. drivers/target/iscsi/iscsi_target_tq.c )

    if (!strncmp(current->comm, ISCSI_RX_THREAD_NAME,
                 strlen(ISCSI_RX_THREAD_NAME)))
        thread_called = ISCSI_RX_THREAD;
    else if (!strncmp(current->comm, ISCSI_TX_THREAD_NAME,
                      strlen(ISCSI_TX_THREAD_NAME)))
        thread_called = ISCSI_TX_THREAD;

commcmp() and commcpy() are for wrappring (a).
Though (a) should consider changing to (b) or (c).

(e) should be rewritten not to depend on current->comm .