linux-kernel - [PATCH net-next 01/10] net: ipa: kill replenish

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Date:   Thu,  3 Feb 2022 11:09:18 -0600
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     bjorn.andersson@...aro.org, mka@...omium.org, evgreen@...omium.org,
        cpratapa@...eaurora.org, avuyyuru@...eaurora.org,
        jponduru@...eaurora.org, subashab@...eaurora.org, elder@...nel.org,
        netdev@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next 01/10] net: ipa: kill replenish_saved

The replenish_saved field keeps track of the number of times a new
buffer is added to the backlog when replenishing is disabled.  We
don't really use it though, so there's no need for us to track it
separately.  Whether replenishing is enabled or not, we can simply
increment the backlog.

Get rid of replenish_saved, and initialize and increment the backlog
where it would have otherwise been used.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 17 ++++-------------
 drivers/net/ipa/ipa_endpoint.h |  2 --
 2 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index fffd0a784ef2c..a9f6d4083f869 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1090,9 +1090,8 @@ static int ipa_endpoint_replenish_one(struct ipa_endpoint *endpoint)
  * 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.
+ * an endpoint can be disabled, in which case buffers are not queued to
+ * the hardware.
  */
 static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
 {
@@ -1102,7 +1101,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
 
 	if (!test_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags)) {
 		if (add_one)
-			atomic_inc(&endpoint->replenish_saved);
+			atomic_inc(&endpoint->replenish_backlog);
 		return;
 	}
 
@@ -1147,11 +1146,8 @@ static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
 {
 	struct gsi *gsi = &endpoint->ipa->gsi;
 	u32 max_backlog;
-	u32 saved;
 
 	set_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
-	while ((saved = atomic_xchg(&endpoint->replenish_saved, 0)))
-		atomic_add(saved, &endpoint->replenish_backlog);
 
 	/* Start replenishing if hardware currently has no buffers */
 	max_backlog = gsi_channel_tre_max(gsi, endpoint->channel_id);
@@ -1161,11 +1157,7 @@ static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
 
 static void ipa_endpoint_replenish_disable(struct ipa_endpoint *endpoint)
 {
-	u32 backlog;
-
 	clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
-	while ((backlog = atomic_xchg(&endpoint->replenish_backlog, 0)))
-		atomic_add(backlog, &endpoint->replenish_saved);
 }
 
 static void ipa_endpoint_replenish_work(struct work_struct *work)
@@ -1727,9 +1719,8 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
 		 */
 		clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
 		clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
-		atomic_set(&endpoint->replenish_saved,
+		atomic_set(&endpoint->replenish_backlog,
 			   gsi_channel_tre_max(gsi, endpoint->channel_id));
-		atomic_set(&endpoint->replenish_backlog, 0);
 		INIT_DELAYED_WORK(&endpoint->replenish_work,
 				  ipa_endpoint_replenish_work);
 	}
diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h
index 0313cdc607de3..c95816d882a74 100644
--- a/drivers/net/ipa/ipa_endpoint.h
+++ b/drivers/net/ipa/ipa_endpoint.h
@@ -66,7 +66,6 @@ enum ipa_replenish_flag {
  * @netdev:		Network device pointer, if endpoint uses one
  * @replenish_flags:	Replenishing state flags
  * @replenish_ready:	Number of replenish transactions without doorbell
- * @replenish_saved:	Replenish requests held while disabled
  * @replenish_backlog:	Number of buffers needed to fill hardware queue
  * @replenish_work:	Work item used for repeated replenish failures
  */
@@ -87,7 +86,6 @@ struct ipa_endpoint {
 	/* Receive buffer replenishing for RX endpoints */
 	DECLARE_BITMAP(replenish_flags, IPA_REPLENISH_COUNT);
 	u32 replenish_ready;
-	atomic_t replenish_saved;
 	atomic_t replenish_backlog;
 	struct delayed_work replenish_work;		/* global wq */
 };
-- 
2.32.0