FAILED: patch "[PATCH] net: ipa: prevent concurrent replenish" failed to apply to 5.16-stable tree

The patch below does not apply to the 5.16-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 998c0bd2b3715244da7639cc4e6a2062cb79c3f4 Mon Sep 17 00:00:00 2001
From: Alex Elder <[email protected]>
Date: Wed, 12 Jan 2022 07:30:12 -0600
Subject: [PATCH] net: ipa: prevent concurrent replenish

We have seen cases where an endpoint RX completion interrupt arrives while replenishing for the endpoint is underway. This causes another instance of replenishing to begin as part of completing the receive transaction. If this occurs it can lead to transaction corruption.

Use a new flag to ensure only one replenish instance for an endpoint executes at a time.

Fixes 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")

Signed-off-by Alex Elder <[email protected]>

Signed-off-by David S. Miller <[email protected]>

drivers/net/ipa/ipa_endpoint.c +13 -0

index cddddcedaf72..68291a3efd04 100644
@@ -1088,15 +1088,27 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
  		return;
  	}
 
+	/* If already active, just update the backlog */
+	if (test_and_set_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags)) {
+		if (add_one)
+			atomic_inc(&endpoint->replenish_backlog);
+		return;
+	}
+
  	while (atomic_dec_not_zero(&endpoint->replenish_backlog))
  		if (ipa_endpoint_replenish_one(endpoint))
  			goto try_again_later;
+
+	clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
+
  	if (add_one)
  		atomic_inc(&endpoint->replenish_backlog);
 
  	return;
 
  try_again_later:
+	clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
+
  	/* The last one didn't succeed, so fix the backlog */
  	delta = add_one ? 2 : 1;
  	backlog = atomic_add_return(delta, &endpoint->replenish_backlog);

@@ -1691,6 +1703,7 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
  		 * backlog is the same as the maximum outstanding TREs.
  		 */
  		clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
+		clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
  		atomic_set(&endpoint->replenish_saved,
  			   gsi_channel_tre_max(gsi, endpoint->channel_id));
  		atomic_set(&endpoint->replenish_backlog, 0);

drivers/net/ipa/ipa_endpoint.h +2 -0

index 07d5c20e5f00..0313cdc607de 100644
@@ -44,10 +44,12 @@ enum ipa_endpoint_name {
   * enum ipa_replenish_flag:	RX buffer replenish flags
   *
   * @IPA_REPLENISH_ENABLED:	Whether receive buffer replenishing is enabled
+ * @IPA_REPLENISH_ACTIVE:	Whether replenishing is underway
   * @IPA_REPLENISH_COUNT:	Number of defined replenish flags
   */
  enum ipa_replenish_flag {
  	IPA_REPLENISH_ENABLED,
+	IPA_REPLENISH_ACTIVE,
  	IPA_REPLENISH_COUNT,	/* Number of flags (must be last) */
  };
 

Quoted 5 lines · On 1/24/22 7:37 AM, [email protected] wrote:

The patch below does not apply to the 5.16-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Sorry about that.

Unfortunately, the commit in question:

998c0bd2b3715 net: ipa: prevent concurrent replenish

has one predecessor commit as a prerequisite:

c1aaa01dbf4ce net: ipa: use a bitmap for endpoint replenish_enabled

I find that I can cleanly cherry-pick the two commits on top of tag "v5.16.4" cleanly. I.e.:

  git reset --hard v5.16.4
  git cherry-pick -x c1aaa01dbf4ce 998c0bd2b3715

Is that an adequate solution? If not, I can supply patches that do essentially that.

This works on tag "v5.15.18" as well.