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Groups > linux.kernel > #1722915
| From | Steven Rostedt <rostedt@goodmis.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: printk: what is going on with additional newlines? |
| Date | 2017-08-30 02:00 +0200 |
| Message-ID | <ujYAi-LM-9@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <ujrl0-5xq-21@gated-at.bofh.it> <ujrEm-5DK-23@gated-at.bofh.it> <ujP3X-3gG-1@gated-at.bofh.it> <ujSbw-5nB-15@gated-at.bofh.it> <ujSlb-5rP-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, 29 Aug 2017 10:12:22 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Tue, Aug 29, 2017 at 10:00 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > I refuse to help those things. We mis-designed things
>
> Actually, let me rephrase that:
>
> It might actually be a good idea to help those things, by making
> helper functions available that do the marshalling.
>
> So not calling "printk()" directly, but having a set of simple
> "buffer_print()" functions where each user has its own buffer, and
> then the "buffer_print()" functions will help people do nicely output
> data.
>
> So if the issue is that people want to print (for example) hex dumps
> one character at a time, but don't want to have each character show up
> on a line of their own, I think we might well add a few functions to
> help dop that.
>
> But they wouldn't be "printk". They would be the buffering functions
> that then call printk when tyhey have buffered a line.
>
> That avoids the whole nasty issue with printk - printk wants to show
> stuff early (because _maybe_ it's critical) and printk wants to make
> log records with timestamps and loglevels. And printk has serious
> locking issues that are really nasty and fundamental.
>
> A private buffer has none of those issues.
What about using the seq_buf*() then?
struct seq_buf s;
buf = kmalloc(mysize);
seq_buf_init(&s, buf, mysize);
seq_printf(&s,"blah blah %d", bah_blah);
[...]
seq_printf(&s, "my last print\n");
printk("%.*s", s.len, s.buffer);
kfree(buf);
This is what the NMI "safe" printks basically do.
-- Steve
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 11:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 12:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-28 14:40 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-28 14:50 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-29 15:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 18:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:10 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:20 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-08-29 22:50 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 23:00 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-02 08:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-02 19:10 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 02:00 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-30 02:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-08-30 03:20 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 04:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 04:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-30 05:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 07:40 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-08 12:20 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 11:50 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 12:10 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-05 14:30 +0200
Re: printk: what is going on with additional newlines? Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-09-05 14:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-05 16:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-05 15:50 +0200
Re: printk: what is going on with additional newlines? Petr Mladek <pmladek@suse.com> - 2017-09-06 10:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-09-01 15:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-01 22:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-04 07:50 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-05 17:00 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-06 04:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-09-06 04:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 06:40 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-04 07:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 20:00 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 20:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:10 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-08-30 03:00 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 18:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:20 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:30 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-29 19:40 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-08-29 19:50 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-08-29 22:30 +0200
Re: printk: what is going on with additional newlines? Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2017-09-01 03:50 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 04:10 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:00 +0200
Re: printk: what is going on with additional newlines? Joe Perches <joe@perches.com> - 2017-09-01 09:30 +0200
Re: printk: what is going on with additional newlines? Pavel Machek <pavel@ucw.cz> - 2017-09-01 09:30 +0200
Re: printk: what is going on with additional newlines? Steven Rostedt <rostedt@goodmis.org> - 2017-09-01 13:20 +0200
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