[PATCH 01/10] x86, mce: remove tsc handling from mce_read

From: Hidetoshi Seto
Date: Mon Oct 05 2009 - 02:34:45 EST


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@xxxxxxxxx>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
---
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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