I've been staring at the BKL lock in cpuid_open, and I can't see what it
is protecting. However, I may have missed something - even something
obvious, so comments are welcome.
>From 25c0f07b3ec5533c0e690e06198baa4300ee4a8c Mon Sep 17 00:00:00 2001
From: John Kacur <jkacur@xxxxxxxxxx>
Date: Wed, 7 Oct 2009 20:06:12 +0200
Subject: [PATCH] The BKL is not necessary in cpuid_open
Most of the variables are local to the function. It IS possible that for
struct cpuinfo_x86 *c
c could point to the same area. However, this is used read only.
Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
---
arch/x86/kernel/cpuid.c | 3 ---
1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 6a52d4b..8bb8401 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -118,8 +118,6 @@ static int cpuid_open(struct inode *inode, struct file *file)
struct cpuinfo_x86 *c;
int ret = 0;
- lock_kernel();
-
cpu = iminor(file->f_path.dentry->d_inode);
if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
ret = -ENXIO; /* No such CPU */
@@ -129,7 +127,6 @@ static int cpuid_open(struct inode *inode, struct file *file)
if (c->cpuid_level < 0)
ret = -EIO; /* CPUID not supported */
out:
- unlock_kernel();
return ret;
}
--
1.6.0.6
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