From 350abddb1cea770efe2d97012a6e2303f55171e6 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Tue, 10 May 2022 20:14:36 +0800 Subject: [PATCH] net: ipa: fix atomic update in ipa_endpoint_replenish() stable inclusion from stable-v5.10.97 commit 2ed912e3e057b2e883cade4dcf9be74fcc5a7e82 bugzilla: https://gitee.com/openeuler/kernel/issues/I55O0O Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2ed912e3e057b2e883cade4dcf9be74fcc5a7e82 -------------------------------- 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 Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints") Signed-off-by: Alex Elder Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yu Liao Reviewed-by: Wei Li Signed-off-by: Zheng Zengkai --- drivers/net/ipa/ipa_endpoint.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index a37aae00e128..397323f9e5d6 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -918,10 +918,7 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, u32 count) try_again_later: /* 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); + backlog = atomic_add_return(count + 1, &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 -- GitLab