Commit f66a4976 authored by Eli Billauer's avatar Eli Billauer Committed by Greg Kroah-Hartman
Browse files

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



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: default avatarEli Billauer <eli.billauer@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a5b2e028

drivers/staging/xillybus/xillybus_core.c

+0 −4
Original line number Diff line number Diff line
@@ -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);

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