[PATCH net-next 1/7] net: ipa: restructure a few functions

[Alex Elder <elder@linaro.org>]

Make __gsi_channel_start() and __gsi_channel_stop() more structurally
and semantically similar to each other:
  - Restructure __gsi_channel_start() to always return at the end of
    the function, similar to the way __gsi_channel_stop() does.
  - Move the mutex calls out of gsi_channel_stop_retry() and into
    __gsi_channel_stop().

Restructure gsi_channel_stop() to always return at the end of the
function, like gsi_channel_start() does.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/gsi.c | 45 +++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 53640447bf123..2671b76ebcfe3 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -873,17 +873,17 @@ static void gsi_channel_deprogram(struct gsi_channel *channel)
 
 static int __gsi_channel_start(struct gsi_channel *channel, bool start)
 {
-	struct gsi *gsi = channel->gsi;
-	int ret;
+	int ret = 0;
 
-	if (!start)
-		return 0;
+	if (start) {
+		struct gsi *gsi = channel->gsi;
 
-	mutex_lock(&gsi->mutex);
+		mutex_lock(&gsi->mutex);
 
-	ret = gsi_channel_start_command(channel);
+		ret = gsi_channel_start_command(channel);
 
-	mutex_unlock(&gsi->mutex);
+		mutex_unlock(&gsi->mutex);
+	}
 
 	return ret;
 }
@@ -910,11 +910,8 @@ int gsi_channel_start(struct gsi *gsi, u32 channel_id)
 static int gsi_channel_stop_retry(struct gsi_channel *channel)
 {
 	u32 retries = GSI_CHANNEL_STOP_RETRIES;
-	struct gsi *gsi = channel->gsi;
 	int ret;
 
-	mutex_lock(&gsi->mutex);
-
 	do {
 		ret = gsi_channel_stop_command(channel);
 		if (ret != -EAGAIN)
@@ -922,19 +919,26 @@ static int gsi_channel_stop_retry(struct gsi_channel *channel)
 		usleep_range(3 * USEC_PER_MSEC, 5 * USEC_PER_MSEC);
 	} while (retries--);
 
-	mutex_unlock(&gsi->mutex);
-
 	return ret;
 }
 
 static int __gsi_channel_stop(struct gsi_channel *channel, bool stop)
 {
-	int ret;
+	int ret = 0;
 
 	/* Wait for any underway transactions to complete before stopping. */
 	gsi_channel_trans_quiesce(channel);
 
-	ret = stop ? gsi_channel_stop_retry(channel) : 0;
+	if (stop) {
+		struct gsi *gsi = channel->gsi;
+
+		mutex_lock(&gsi->mutex);
+
+		ret = gsi_channel_stop_retry(channel);
+
+		mutex_unlock(&gsi->mutex);
+	}
+
 	/* Finally, ensure NAPI polling has finished. */
 	if (!ret)
 		napi_synchronize(&channel->napi);
@@ -948,15 +952,14 @@ int gsi_channel_stop(struct gsi *gsi, u32 channel_id)
 	struct gsi_channel *channel = &gsi->channel[channel_id];
 	int ret;
 
-	/* Only disable the completion interrupt if stop is successful */
 	ret = __gsi_channel_stop(channel, true);
-	if (ret)
-		return ret;
+	if (ret) {
+		/* Disable the completion interrupt and NAPI if successful */
+		gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
+		napi_disable(&channel->napi);
+	}
 
-	gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
-	napi_disable(&channel->napi);
-
-	return 0;
+	return ret;
 }
 
 /* Reset and reconfigure a channel, (possibly) enabling the doorbell engine */
-- 
2.20.1