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Subject[PATCH] block: reduce spin_lock critical region
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the critical region is originally composed by a conditional plus
a memory copy, the memory copy routine don't need protection.
Moving the memcpy() outside the conditional also help to fix the
16 compiler warning messages generated in __u8 sn[16] def.

Signed-off-by: Eduardo Silva <edsiper@gmail.com>
---
drivers/block/cciss.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 9bf1398..199b35e 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -621,20 +621,19 @@ static ssize_t dev_show_unique_id(struct device *dev,
spin_lock_irqsave(&h->lock, flags);
if (h->busy_configuring)
ret = -EBUSY;
- else
- memcpy(sn, drv->serial_no, sizeof(sn));
spin_unlock_irqrestore(&h->lock, flags);

if (ret)
return ret;
- else
- return snprintf(buf, 16 * 2 + 2,
- "%02X%02X%02X%02X%02X%02X%02X%02X"
- "%02X%02X%02X%02X%02X%02X%02X%02X\n",
- sn[0], sn[1], sn[2], sn[3],
- sn[4], sn[5], sn[6], sn[7],
- sn[8], sn[9], sn[10], sn[11],
- sn[12], sn[13], sn[14], sn[15]);
+
+ memcpy(sn, drv->serial_no, sizeof(sn));
+ return snprintf(buf, 16 * 2 + 2,
+ "%02X%02X%02X%02X%02X%02X%02X%02X"
+ "%02X%02X%02X%02X%02X%02X%02X%02X\n",
+ sn[0], sn[1], sn[2], sn[3],
+ sn[4], sn[5], sn[6], sn[7],
+ sn[8], sn[9], sn[10], sn[11],
+ sn[12], sn[13], sn[14], sn[15]);
}
static DEVICE_ATTR(unique_id, S_IRUGO, dev_show_unique_id, NULL);

--
1.7.4.1




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