linux-kernel - [PATCH] nvram: Drop the bkl from nvram

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Date:	Fri,  9 Oct 2009 21:20:30 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, John Kacur <jkacur@...hat.com>,
	Sven-Thorsten Dietrich <sven@...bigcorporation.com>,
	Jonathan Corbet <corbet@....net>,
	Alessio Igor Bogani <abogani@...ware.it>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Greg KH <gregkh@...e.de>
Subject: [PATCH] nvram: Drop the bkl from nvram_llseek()

There is nothing to protect inside nvram_llseek(), the file
offset doesn't need to be protected and nvram_len is only
initialized from an __init path.

It's safe to remove the big kernel lock there.

(Is this file still used? I can't even build it,
looks like it is built under CONFIG_GENERIC_NVRAM but this
option is referenced nowhere except in powerpc defconfigs)

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: John Kacur <jkacur@...hat.com>
Cc: Sven-Thorsten Dietrich <sven@...bigcorporation.com>
Cc: Jonathan Corbet <corbet@....net>
Cc: Alessio Igor Bogani <abogani@...ware.it>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Greg KH <gregkh@...e.de>
---
 drivers/char/generic_nvram.c |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c
index ef31738..c49200e 100644
--- a/drivers/char/generic_nvram.c
+++ b/drivers/char/generic_nvram.c
@@ -32,7 +32,6 @@ static ssize_t nvram_len;
 
 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
 {
-	lock_kernel();
 	switch (origin) {
 	case 1:
 		offset += file->f_pos;
@@ -41,12 +40,11 @@ static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
 		offset += nvram_len;
 		break;
 	}
-	if (offset < 0) {
-		unlock_kernel();
+	if (offset < 0)
 		return -EINVAL;
-	}
+
 	file->f_pos = offset;
-	unlock_kernel();
+
 	return file->f_pos;
 }
 
-- 
1.6.2.3

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