linux-kernel - [PATCH 01/10] x86, mce: remove tsc handling from mce

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Date:	Mon, 05 Oct 2009 15:33:21 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	Huang Ying <ying.huang@...el.com>
CC:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Andi Kleen <ak@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 01/10] x86, mce: remove tsc handling from mce_read

This handling (looks too buggy) is no longer required.

(This piece originates from Huang's patch, titled:
 "x86, MCE: Fix bugs and issues of MCE log ring buffer")

Originally-From: Huang Ying <ying.huang@...el.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
---
 arch/x86/kernel/cpu/mcheck/mce.c |   30 ------------------------------
 1 files changed, 0 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a6d5d4a..28e1e14 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1449,34 +1449,21 @@ static int mce_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static void collect_tscs(void *data)
-{
-	unsigned long *cpu_tsc = (unsigned long *)data;
-
-	rdtscll(cpu_tsc[smp_processor_id()]);
-}
-
 static DEFINE_MUTEX(mce_read_mutex);
 
 static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
 			loff_t *off)
 {
 	char __user *buf = ubuf;
-	unsigned long *cpu_tsc;
 	unsigned prev, next;
 	int i, err;
 
-	cpu_tsc = kmalloc(nr_cpu_ids * sizeof(long), GFP_KERNEL);
-	if (!cpu_tsc)
-		return -ENOMEM;
-
 	mutex_lock(&mce_read_mutex);
 	next = rcu_dereference(mcelog.next);
 
 	/* Only supports full reads right now */
 	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
 		mutex_unlock(&mce_read_mutex);
-		kfree(cpu_tsc);
 
 		return -EINVAL;
 	}
@@ -1511,24 +1498,7 @@ timeout:
 
 	synchronize_sched();
 
-	/*
-	 * Collect entries that were still getting written before the
-	 * synchronize.
-	 */
-	on_each_cpu(collect_tscs, cpu_tsc, 1);
-
-	for (i = next; i < MCE_LOG_LEN; i++) {
-		if (mcelog.entry[i].finished &&
-		    mcelog.entry[i].tsc < cpu_tsc[mcelog.entry[i].cpu]) {
-			err |= copy_to_user(buf, mcelog.entry+i,
-					    sizeof(struct mce));
-			smp_rmb();
-			buf += sizeof(struct mce);
-			memset(&mcelog.entry[i], 0, sizeof(struct mce));
-		}
-	}
 	mutex_unlock(&mce_read_mutex);
-	kfree(cpu_tsc);
 
 	return err ? -EFAULT : buf - ubuf;
 }
-- 
1.6.4.3


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