From fedc777d6716f78dd82bf2ffbe30e8413de54332 Mon Sep 17 00:00:00 2001
From: Alex Elder <elder@linaro.org>
Date: Wed, 12 Jan 2022 07:30:10 -0600
Subject: [PATCH 03/34] net: ipa: fix atomic update in ipa_endpoint_replenish()
Git-commit: 6c0e3b5ce94947b311348c367db9e11dcb2ccc93
References: git-fixes
Patch-mainline: v5.17-rc1
In ipa_endpoint_replenish(), if an error occurs when attempting to
replenish a receive buffer, we just quit and try again later. In
that case we increment the backlog count to reflect that the attempt
was unsuccessful. Then, if the add_one flag was true we increment
the backlog again.
This second increment is not included in the backlog local variable
though, and its value determines whether delayed work should be
scheduled. This is a bug.
Fix this by determining whether 1 or 2 should be added to the
backlog before adding it in a atomic_add_return() call.
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/ipa/ipa_endpoint.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 1c6dcb1bd8c9..be1ce3b1ef07 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1064,6 +1064,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
{
struct gsi *gsi;
u32 backlog;
+ int delta;
if (!endpoint->replenish_enabled) {
if (add_one)
@@ -1081,10 +1082,8 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
try_again_later:
/* The last one didn't succeed, so fix the backlog */
- backlog = atomic_inc_return(&endpoint->replenish_backlog);
-
- if (add_one)
- atomic_inc(&endpoint->replenish_backlog);
+ delta = add_one ? 2 : 1;
+ backlog = atomic_add_return(delta, &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
--
2.16.4