linux-kernel - [PATCH v3 2/8] android_pipe: don't be clever with #define offsets

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Message-Id: <1449084968-30211-2-git-send-email-jinqian@android.com>
Date:	Wed,  2 Dec 2015 11:35:57 -0800
From:	Jin Qian <jinqian@...roid.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Greg Hackmann <ghackmann@...gle.com>,
	Joe Perches <joe@...ches.com>,
	Christoffer Dall <christoffer.dall@...aro.org>,
	Peter Senna Tschudin <peter.senna@...il.com>,
	Jason Hu <jia-cheng.hu@...el.com>,
	Alex Bennée <alex.bennee@...aro.org>,
	Yu Ning <yu.ning@...el.com>, linux-kernel@...r.kernel.org
Cc:	Jin Qian <jinqian@...roid.com>
Subject: [PATCH v3 2/8] android_pipe: don't be clever with #define offsets

From: Alex Bennée <alex.bennee@...aro.org>

You just make it harder to figure out when commands are being used.

Signed-off-by: Alex Bennée <alex.bennee@...aro.org>
Signed-off-by: Jin Qian <jinqian@...roid.com>
---
 drivers/platform/goldfish/goldfish_pipe.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index e7a29e2..0fb3a34 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -90,12 +90,6 @@
 #define CMD_WRITE_BUFFER	4  /* send a user buffer to the emulator */
 #define CMD_WAKE_ON_WRITE	5  /* tell the emulator to wake us when writing
 				     is possible */
-
-/* The following commands are related to read operations, they must be
- * listed in the same order than the corresponding write ones, since we
- * will use (CMD_READ_BUFFER - CMD_WRITE_BUFFER) as a special offset
- * in goldfish_pipe_read_write() below.
- */
 #define CMD_READ_BUFFER        6  /* receive a user buffer from the emulator */
 #define CMD_WAKE_ON_READ       7  /* tell the emulator to wake us when reading
 				   * is possible */
@@ -272,8 +266,6 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 	unsigned long irq_flags;
 	struct goldfish_pipe *pipe = filp->private_data;
 	struct goldfish_pipe_dev *dev = pipe->dev;
-	const int cmd_offset = is_write ? 0
-					: (CMD_READ_BUFFER - CMD_WRITE_BUFFER);
 	unsigned long address, address_end;
 	int ret = 0;
 
@@ -325,7 +317,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 
 		/* Now, try to transfer the bytes in the current page */
 		spin_lock_irqsave(&dev->lock, irq_flags);
-		if (access_with_param(dev, CMD_WRITE_BUFFER + cmd_offset,
+		if (access_with_param(dev,
+				is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
 				address, avail, pipe, &status)) {
 			gf_write_ptr(pipe, dev->base + PIPE_REG_CHANNEL,
 				     dev->base + PIPE_REG_CHANNEL_HIGH);
@@ -333,7 +326,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 			gf_write_ptr((void *)address,
 				     dev->base + PIPE_REG_ADDRESS,
 				     dev->base + PIPE_REG_ADDRESS_HIGH);
-			writel(CMD_WRITE_BUFFER + cmd_offset,
+			writel(is_write ? CMD_WRITE_BUFFER : CMD_READ_BUFFER,
 					dev->base + PIPE_REG_COMMAND);
 			status = readl(dev->base + PIPE_REG_STATUS);
 		}
@@ -370,7 +363,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		set_bit(wakeBit, &pipe->flags);
 
 		/* Tell the emulator we're going to wait for a wake event */
-		goldfish_cmd(pipe, CMD_WAKE_ON_WRITE + cmd_offset);
+		goldfish_cmd(pipe,
+			is_write ? CMD_WAKE_ON_WRITE : CMD_WAKE_ON_READ);
 
 		/* Unlock the pipe, then wait for the wake signal */
 		mutex_unlock(&pipe->lock);
-- 
2.6.0.rc2.230.g3dd15c0

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