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 6c0e3b5c 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: NMatthias Kaehlcke <mka@chromium.org>
Fixes: 84f9bd12 ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: NAlex Elder <elder@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

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