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SubjectRe: [PATCHv7 4/8] printk: always use deferred printk when flush printk_safe lines
On Tue, 27 Dec 2016 23:16:07 +0900
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote:

> Always use printk_deferred() in printk_safe_flush_line().
> Flushing can be done from NMI or printk_safe contexts (when
> we are in panic), so we can't call console drivers, yet still
> want to store the messages in the logbuf buffer. Therefore we
> use a deferred printk version.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Suggested-by: Petr Mladek <pmladek@suse.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> ---
> kernel/printk/printk_safe.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
> index efc89a4e9df5..054c9128ade0 100644
> --- a/kernel/printk/printk_safe.c
> +++ b/kernel/printk/printk_safe.c
> @@ -113,14 +113,12 @@ static int printk_safe_log_store(struct printk_safe_seq_buf *s,
> static void printk_safe_flush_line(const char *text, int len)
> {
> /*
> - * The buffers are flushed in NMI only on panic. The messages must
> - * go only into the ring buffer at this stage. Consoles will get
> - * explicitly called later when a crashdump is not generated.
> + * Avoid any console drivers calls from here, because we may be
> + * in NMI or printk_safe context (when in panic). The messages
> + * must go only into the ring buffer at this stage. Consoles will
> + * get explicitly called later when a crashdump is not generated.
> */
> - if (in_nmi())
> - printk_deferred("%.*s", len, text);
> - else
> - printk("%.*s", len, text);
> + printk_deferred("%.*s", len, text);
> }

The helper function was there because of the if statement. Just nuke
this function and call printk_deferred() directly. You can move the
comment to the caller.

-- Steve

>
> /* printk part of the temporary buffer line by line */

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