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staging: xillybus: Removed mmiowb() before mutex_unlock()

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The relevant sequences consist of two I/O memory writes. The second write
depends on the first one. mmiowb() was inserted to make sure that no other
thread inserts a "first write" before the current one finished its second.

As a mutex protects this critical sequence, mmiowb() is unnecessary.

Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eli Billauer
2014-08-16 18:57:57 +03:00
committed by Greg Kroah-Hartman
parent a5b2e028bb
commit f66a49766f
1 changed files with 0 additions and 4 deletions
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4
drivers/staging/xillybus/xillybus_core.c
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@@ -908,8 +908,6 @@ static ssize_t xillybus_read(struct file *filp, char __user *userbuf,
channel->endpoint->registers +
fpga_buf_ctrl_reg);
mmiowb(); /* Just to appear safe */
mutex_unlock(&channel->endpoint->
register_mutex);
}
@@ -1118,7 +1116,6 @@ static int xillybus_myflush(struct xilly_channel *channel, long timeout)
(2 << 24) | /* Opcode 2, submit buffer */
(bufidx << 12),
channel->endpoint->registers + fpga_buf_ctrl_reg);
mmiowb(); /* Just to appear safe */
mutex_unlock(&channel->endpoint->register_mutex);
} else if (bufidx == 0)
@@ -1369,7 +1366,6 @@ static ssize_t xillybus_write(struct file *filp, const char __user *userbuf,
(bufidx << 12),
channel->endpoint->registers +
fpga_buf_ctrl_reg);
mmiowb(); /* Just to appear safe */
mutex_unlock(&channel->endpoint->
register_mutex);