linux-kernel - [PATCH 3/5] printk: Split message size computation

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Message-Id: <1397122996-15136-4-git-send-email-pmladek@suse.cz>
Date:	Thu, 10 Apr 2014 11:43:14 +0200
From:	Petr Mladek <pmladek@...e.cz>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Jan Kara <jack@...e.cz>, Jiri Kosina <jkosina@...e.cz>,
	Kay Sievers <kay@...y.org>, linux-kernel@...r.kernel.org,
	Petr Mladek <pmladek@...e.cz>
Subject: [PATCH 3/5] printk: Split message size computation

We will want to recompute the message size when shrinking too long messages.
Let's put the code into separate function.

The side effect of setting "pad_len" is not nice but it is worth removing
the code duplication. Note that I will probably have one more usage for this
function when handling messages safe way in NMI context.

This patch does not change the existing behavior.

Signed-off-by: Petr Mladek <pmladek@...e.cz>
---
 kernel/printk/printk.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 5de686b6b9e1..7416dfad0a28 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -339,6 +339,18 @@ static int log_make_free_space(u32 msg_size)
 	return -ENOMEM;
 }
 
+/* compute the message size including the padding bytes */
+static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len)
+{
+	u32 size;
+
+	size = sizeof(struct printk_log) + text_len + dict_len;
+	*pad_len = (-size) & (LOG_ALIGN - 1);
+	size += *pad_len;
+
+	return size;
+}
+
 /* insert record into the buffer, discard old ones, update heads */
 static void log_store(int facility, int level,
 		      enum log_flags flags, u64 ts_nsec,
@@ -349,9 +361,7 @@ static void log_store(int facility, int level,
 	u32 size, pad_len;
 
 	/* number of '\0' padding bytes to next message */
-	size = sizeof(struct printk_log) + text_len + dict_len;
-	pad_len = (-size) & (LOG_ALIGN - 1);
-	size += pad_len;
+	size = msg_used_size(text_len, dict_len, &pad_len);
 
 	/* if message does not fit empty log buffer, ignore it */
 	if (log_make_free_space(size))
-- 
1.8.4

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