From: John Ogness Date: Thu, 28 Mar 2024 13:29:10 +0000 Subject: [PATCH 39/48] printk: Provide helper for message prepending Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz In order to support prepending different texts to printk messages, split out the prepending code into a helper function. Signed-off-by: John Ogness Signed-off-by: Sebastian Andrzej Siewior --- kernel/printk/printk.c | 38 +++++++++++++++++++++++++++----------- 1 file changed, 27 insertions(+), 11 deletions(-) --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2819,30 +2819,25 @@ 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 with the message in + * @pmsg->pbufs->scratchbuf. 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. + * @len is the length of the message in @pmsg->pbufs->scratchbuf. * * If the message text in @pmsg->pbufs->outbuf does not have enough space for - * the dropped message, the message text will be sufficiently truncated. + * the scratchbuf message, the 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) +static void __console_prepend_scratch(struct printk_message *pmsg, size_t len) { 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]; - size_t len; - - len = scnprintf(scratchbuf, scratchbuf_sz, - "** %lu printk messages dropped **\n", dropped); /* * Make sure outbuf is sufficiently large before prepending. @@ -2865,6 +2860,27 @@ void console_prepend_dropped(struct prin } /* + * 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) +{ + struct printk_buffers *pbufs = pmsg->pbufs; + const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf); + char *scratchbuf = &pbufs->scratchbuf[0]; + size_t len; + + len = scnprintf(scratchbuf, scratchbuf_sz, + "** %lu printk messages dropped **\n", dropped); + + __console_prepend_scratch(pmsg, len); +} + +/* * Read and format the specified record (or a later record if the specified * record is not available). *