linux-kernel - [PATCH net-next v2 5/7] net: ipa: use a Boolean rather than count when replenishing

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Message-Id: <20210205221100.1738-6-elder@linaro.org>
Date:   Fri,  5 Feb 2021 16:10:58 -0600
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     elder@...nel.org, evgreen@...omium.org, bjorn.andersson@...aro.org,
        cpratapa@...eaurora.org, subashab@...eaurora.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next v2 5/7] net: ipa: use a Boolean rather than count when replenishing

The count argument to ipa_endpoint_replenish() is only ever 0 or 1,
and always will be (because we always handle each receive buffer in
a single transaction).  Rename the argument to be add_one and change
it to be Boolean.

Update the function description to reflect the current code.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 35 ++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 7a46c790afbef..bff5d6ffd1186 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1020,31 +1020,34 @@ static int ipa_endpoint_replenish_one(struct ipa_endpoint *endpoint)
 }
 
 /**
- * ipa_endpoint_replenish() - Replenish the Rx packets cache.
+ * ipa_endpoint_replenish() - Replenish endpoint receive buffers
  * @endpoint:	Endpoint to be replenished
- * @count:	Number of buffers to send to hardware
+ * @add_one:	Whether this is replacing a just-consumed buffer
  *
- * Allocate RX packet wrapper structures with maximal socket buffers
- * for an endpoint.  These are supplied to the hardware, which fills
- * them with incoming data.
+ * The IPA hardware can hold a fixed number of receive buffers for an RX
+ * endpoint, based on the number of entries in the underlying channel ring
+ * buffer.  If an endpoint's "backlog" is non-zero, it indicates how many
+ * more receive buffers can be supplied to the hardware.  Replenishing for
+ * an endpoint can be disabled, in which case requests to replenish a
+ * buffer are "saved", and transferred to the backlog once it is re-enabled
+ * again.
  */
-static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, u32 count)
+static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
 {
 	struct gsi *gsi;
 	u32 backlog;
 
 	if (!endpoint->replenish_enabled) {
-		if (count)
-			atomic_add(count, &endpoint->replenish_saved);
+		if (add_one)
+			atomic_inc(&endpoint->replenish_saved);
 		return;
 	}
 
-
 	while (atomic_dec_not_zero(&endpoint->replenish_backlog))
 		if (ipa_endpoint_replenish_one(endpoint))
 			goto try_again_later;
-	if (count)
-		atomic_add(count, &endpoint->replenish_backlog);
+	if (add_one)
+		atomic_inc(&endpoint->replenish_backlog);
 
 	return;
 
@@ -1052,8 +1055,8 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, u32 count)
 	/* The last one didn't succeed, so fix the backlog */
 	backlog = atomic_inc_return(&endpoint->replenish_backlog);
 
-	if (count)
-		atomic_add(count, &endpoint->replenish_backlog);
+	if (add_one)
+		atomic_inc(&endpoint->replenish_backlog);
 
 	/* Whenever a receive buffer transaction completes we'll try to
 	 * replenish again.  It's unlikely, but if we fail to supply even
@@ -1080,7 +1083,7 @@ static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
 	/* Start replenishing if hardware currently has no buffers */
 	max_backlog = gsi_channel_tre_max(gsi, endpoint->channel_id);
 	if (atomic_read(&endpoint->replenish_backlog) == max_backlog)
-		ipa_endpoint_replenish(endpoint, 0);
+		ipa_endpoint_replenish(endpoint, false);
 }
 
 static void ipa_endpoint_replenish_disable(struct ipa_endpoint *endpoint)
@@ -1099,7 +1102,7 @@ static void ipa_endpoint_replenish_work(struct work_struct *work)
 
 	endpoint = container_of(dwork, struct ipa_endpoint, replenish_work);
 
-	ipa_endpoint_replenish(endpoint, 0);
+	ipa_endpoint_replenish(endpoint, false);
 }
 
 static void ipa_endpoint_skb_copy(struct ipa_endpoint *endpoint,
@@ -1300,7 +1303,7 @@ static void ipa_endpoint_rx_complete(struct ipa_endpoint *endpoint,
 {
 	struct page *page;
 
-	ipa_endpoint_replenish(endpoint, 1);
+	ipa_endpoint_replenish(endpoint, true);
 
 	if (trans->cancelled)
 		return;
-- 
2.20.1