This is a note to let you know that I've just added the patch titled
net: ipa: fix atomic update in ipa_endpoint_replenish()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-ipa-fix-atomic-update-in-ipa_endpoint_replenish.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6c0e3b5ce94947b311348c367db9e11dcb2ccc93 Mon Sep 17 00:00:00 2001
From: Alex Elder <elder@xxxxxxxxxx>
Date: Wed, 12 Jan 2022 07:30:10 -0600
Subject: net: ipa: fix atomic update in ipa_endpoint_replenish()
From: Alex Elder <elder@xxxxxxxxxx>
commit 6c0e3b5ce94947b311348c367db9e11dcb2ccc93 upstream.
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@xxxxxxxxxxxx>
Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ipa/ipa_endpoint.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1067,6 +1067,7 @@ static void ipa_endpoint_replenish(struc
{
struct gsi *gsi;
u32 backlog;
+ int delta;
if (!endpoint->replenish_enabled) {
if (add_one)
@@ -1084,10 +1085,8 @@ static void ipa_endpoint_replenish(struc
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
Patches currently in stable-queue which might be from elder@xxxxxxxxxx are
queue-5.15/staging-greybus-audio-check-null-pointer.patch
queue-5.15/arm-dts-qcom-sdx55-fix-ipa-interconnect-definitions.patch
queue-5.15/net-ipa-fix-atomic-update-in-ipa_endpoint_replenish.patch
