linux-kernel - [PATCH printk v4 2/6] printk: ringbuffer: add BLK

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Message-Id: <20200908202859.2736-3-john.ogness@linutronix.de>
Date:   Tue,  8 Sep 2020 22:34:55 +0206
From:   John Ogness <john.ogness@...utronix.de>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrea Parri <parri.andrea@...il.com>,
        Paul McKenney <paulmck@...nel.org>, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH printk v4 2/6] printk: ringbuffer: add BLK_DATALESS() macro

Rather than continually needing to explicitly check @begin and @next
to identify a dataless block, introduce and use a BLK_DATALESS()
macro.

Signed-off-by: John Ogness <john.ogness@...utronix.de>
Reviewed-by: Petr Mladek <pmladek@...e.com>
---
 kernel/printk/printk_ringbuffer.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
index aa6e31a27601..6ee5ebce1450 100644
--- a/kernel/printk/printk_ringbuffer.c
+++ b/kernel/printk/printk_ringbuffer.c
@@ -266,6 +266,8 @@
 
 /* Determine if a logical position refers to a data-less block. */
 #define LPOS_DATALESS(lpos)		((lpos) & 1UL)
+#define BLK_DATALESS(blk)		(LPOS_DATALESS((blk)->begin) && \
+					 LPOS_DATALESS((blk)->next))
 
 /* Get the logical position at index 0 of the current wrap. */
 #define DATA_THIS_WRAP_START_LPOS(data_ring, lpos) \
@@ -1021,7 +1023,7 @@ static unsigned int space_used(struct prb_data_ring *data_ring,
 			       struct prb_data_blk_lpos *blk_lpos)
 {
 	/* Data-less blocks take no space. */
-	if (LPOS_DATALESS(blk_lpos->begin))
+	if (BLK_DATALESS(blk_lpos))
 		return 0;
 
 	if (DATA_WRAPS(data_ring, blk_lpos->begin) == DATA_WRAPS(data_ring, blk_lpos->next)) {
@@ -1054,7 +1056,7 @@ static const char *get_data(struct prb_data_ring *data_ring,
 	struct prb_data_block *db;
 
 	/* Data-less data block description. */
-	if (LPOS_DATALESS(blk_lpos->begin) && LPOS_DATALESS(blk_lpos->next)) {
+	if (BLK_DATALESS(blk_lpos)) {
 		if (blk_lpos->begin == NO_LPOS && blk_lpos->next == NO_LPOS) {
 			*data_size = 0;
 			return "";
-- 
2.20.1