From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>, Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Tejun Heo <tj@kernel.org>,
Calvin Owens <calvinowens@fb.com>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Peter Hurley <peter@hurleysoftware.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCHv7 4/8] printk: always use deferred printk when flush printk_safe lines
Date: Tue, 7 Feb 2017 01:42:53 +0900 [thread overview]
Message-ID: <20170206164253.GA463@tigerII.localdomain> (raw)
In-Reply-To: <20170206082739.18a47c8e@gandalf.local.home>
On (02/06/17 08:27), Steven Rostedt wrote:
[..]
> > > > just in case, the patch (which I prefer to be ignored)
> > >
> > > let's keep printk_safe_flush_line().
> >
> > I do not have strong opinion but I would slightly prefer
> > to keep the helper function. The use of printk_deferred()
> > is a bit tricky and it is better to have only one copy.
> >
> > Steven, could you live with the original patch, please?
>
> Sure, but make it into a static inline.
well, I'll be surprised if gcc doesn't inline that simple one-liner.
attached. no conflicts, the patch can replace 0004.
===8<===8<===
>From 69bbb0f436a2a89ec41a5831c03490e0a78ce12e Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date: Tue, 27 Dec 2016 23:16:07 +0900
Subject: [PATCH] printk: always use deferred printk when flush printk_safe
lines
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>
Signed-off-by: Petr Mladek <pmladek@suse.com>
---
kernel/printk/printk_safe.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index efc89a4e9df5..5214d326d3ba 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -110,17 +110,15 @@ static int printk_safe_log_store(struct printk_safe_seq_buf *s,
return add;
}
-static void printk_safe_flush_line(const char *text, int len)
+static inline 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);
}
/* printk part of the temporary buffer line by line */
--
2.11.0
next prev parent reply other threads:[~2017-02-06 16:43 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-27 14:16 [PATCHv7 0/8] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 1/8] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 2/8] printk: rename nmi.c and exported api Sergey Senozhatsky
2017-01-04 13:07 ` Petr Mladek
2017-02-01 15:48 ` Steven Rostedt
2017-02-01 15:50 ` Steven Rostedt
2017-02-23 7:50 ` Geert Uytterhoeven
2017-02-23 8:02 ` Sergey Senozhatsky
2017-02-23 9:23 ` Geert Uytterhoeven
2016-12-27 14:16 ` [PATCHv7 3/8] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2017-01-04 13:31 ` Petr Mladek
2017-01-05 1:01 ` Sergey Senozhatsky
2017-02-01 15:52 ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 4/8] printk: always use deferred printk when flush printk_safe lines Sergey Senozhatsky
2017-02-01 16:06 ` Steven Rostedt
2017-02-02 6:05 ` Sergey Senozhatsky
2017-02-02 15:37 ` Petr Mladek
2017-02-02 15:52 ` Petr Mladek
2017-02-03 2:04 ` Sergey Senozhatsky
2017-02-03 11:18 ` Petr Mladek
2017-02-06 1:48 ` Sergey Senozhatsky
2017-02-06 2:08 ` Sergey Senozhatsky
2017-02-06 12:16 ` Petr Mladek
2017-02-06 13:27 ` Steven Rostedt
2017-02-06 16:42 ` Sergey Senozhatsky [this message]
2017-02-06 16:55 ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 5/8] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2017-01-04 14:46 ` Petr Mladek
2017-01-05 1:01 ` Sergey Senozhatsky
2017-02-01 16:37 ` Steven Rostedt
2017-02-02 2:02 ` Sergey Senozhatsky
2017-02-02 14:34 ` Steven Rostedt
2017-02-02 16:13 ` Petr Mladek
2017-02-03 1:57 ` Sergey Senozhatsky
2017-02-03 3:13 ` Steven Rostedt
2016-12-27 14:16 ` [PATCHv7 6/8] printk: use printk_safe buffers in printk Sergey Senozhatsky
2017-01-31 17:27 ` Ross Zwisler
2017-02-01 9:06 ` Jan Kara
2017-02-01 9:37 ` Peter Zijlstra
2017-02-01 15:39 ` Petr Mladek
2017-02-01 16:15 ` Peter Zijlstra
2017-02-01 16:41 ` Steven Rostedt
2017-02-02 2:11 ` Sergey Senozhatsky
2017-02-02 9:07 ` Peter Zijlstra
2017-02-02 10:03 ` Sergey Senozhatsky
2017-02-02 15:20 ` Petr Mladek
2017-02-03 2:45 ` Sergey Senozhatsky
2017-02-02 1:59 ` Sergey Senozhatsky
2017-02-01 17:04 ` Steven Rostedt
2017-02-02 2:13 ` Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 7/8] printk: remove zap_locks() function Sergey Senozhatsky
2016-12-27 14:16 ` [PATCHv7 8/8] printk: convert the rest to printk-safe Sergey Senozhatsky
2017-01-04 16:28 ` Petr Mladek
2017-01-05 1:00 ` Sergey Senozhatsky
2017-01-05 16:58 ` [PATCHv7 0/8] printk: use printk_safe to handle printk() recursive calls Petr Mladek
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