Commit 75d43037 authored by John Ogness's avatar John Ogness Committed by Petr Mladek
Browse files

printk: Provide helper for message prepending 



In order to support prepending different texts to printk
messages, split out the prepending code into a helper
function.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-11-john.ogness@linutronix.de


Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent 13189fa7

kernel/printk/printk.c

+25 −11
Original line number Diff line number Diff line
@@ -2843,30 +2843,31 @@ static void __console_unlock(void) 
#ifdef CONFIG_PRINTK



/*

 * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message". This

 * is achieved by shifting the existing message over and inserting the dropped

 * message.

 * Prepend the message in @pmsg->pbufs->outbuf. This is achieved by shifting

 * the existing message over and inserting the scratchbuf message.

 *

 * @pmsg is the printk message to prepend.

 *

 * @dropped is the dropped count to report in the dropped message.

 * @pmsg is the original printk message.

 * @fmt is the printf format of the message which will prepend the existing one.

 *

 * If the message text in @pmsg->pbufs->outbuf does not have enough space for

 * the dropped message, the message text will be sufficiently truncated.

 * If there is not enough space in @pmsg->pbufs->outbuf, the existing

 * message text will be sufficiently truncated.

 *

 * If @pmsg->pbufs->outbuf is modified, @pmsg->outbuf_len is updated.

 */

void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped)

__printf(2, 3)

static void console_prepend_message(struct printk_message *pmsg, const char *fmt, ...)

{

	struct printk_buffers *pbufs = pmsg->pbufs;

	const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf);

	const size_t outbuf_sz = sizeof(pbufs->outbuf);

	char *scratchbuf = &pbufs->scratchbuf[0];

	char *outbuf = &pbufs->outbuf[0];

	va_list args;

	size_t len;



	len = scnprintf(scratchbuf, scratchbuf_sz,

		       "** %lu printk messages dropped **\n", dropped);

	va_start(args, fmt);

	len = vscnprintf(scratchbuf, scratchbuf_sz, fmt, args);

	va_end(args);



	/*

	 * Make sure outbuf is sufficiently large before prepending.
@@ -2888,6 +2889,19 @@ void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) 
	pmsg->outbuf_len += len;

}



/*

 * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message".

 * @pmsg->outbuf_len is updated appropriately.

 *

 * @pmsg is the printk message to prepend.

 *

 * @dropped is the dropped count to report in the dropped message.

 */

void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped)

{

	console_prepend_message(pmsg, "** %lu printk messages dropped **\n", dropped);

}



/*

 * Read and format the specified record (or a later record if the specified

 * record is not available).