Messages in this thread |  | | Date | Wed, 23 Sep 2020 17:11:29 +0200 | From | Petr Mladek <> | Subject | Re: [PATCH printk 3/5] printk: use buffer pool for sprint buffers |
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On Tue 2020-09-22 17:44:14, John Ogness wrote: > vprintk_store() is using a single static buffer as a temporary > sprint buffer for the message text. This will not work once > @logbuf_lock is removed. Replace the single static buffer with a > pool of buffers.
The buffer is used because we do not know the length of the formatted message to reserve the right space in the ring buffer in advance.
There was the idea to call vsprintf(NULL, fmt, args) to count the length in advance.
AFAIK, there is one catch. We need to use va_copy() around the 1st call because va_format can be proceed only once. See, va_format() in lib/vsprintf.c as an example.
Is there any other problem, please?
Best Regards, Petr
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