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[73.185.129.58]) by smtp.gmail.com with ESMTPSA id f10sm5218260ilq.64.2021.01.07.13.43.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Jan 2021 13:43:30 -0800 (PST) From: Alex Elder To: davem@davemloft.net, kuba@kernel.org Cc: evgreen@chromium.org, bjorn.andersson@linaro.org, cpratapa@codeaurora.org, subashab@codeaurora.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 2/2] net: ipa: re-enable NAPI before enabling interrupt Date: Thu, 7 Jan 2021 15:43:25 -0600 Message-Id: <20210107214325.7077-3-elder@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210107214325.7077-1-elder@linaro.org> References: <20210107214325.7077-1-elder@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we stop or suspend a channel, we first "freeze" it. The last part of that involves disabling NAPI, and disabling the IEOB interrupt that schedules NAPI when it occurs. On resume, a "thaw" does the inverse of these activities, in reverse order. Currently these are ordered such that NAPI is disabled before interrupts on suspend, and NAPI is re-enabled after interrupts on resume. An interrupt occurring while NAPI is disabled will request a NAPI schedule, but polling is deferred until after NAPI is enabled again. When NAPI is re-enabled, polling is allowed again, but enabling NAPI does not schedule a poll (i.e., it won't trigger polling to handle a schedule request that occurred while disabled). Polling won't commence until the next napi_schedule() request occurs. Instead, disable completion interrupts *before* disabling NAPI when stopping a channel, and re-enable interrupts *after* re-enabling NAPI. That way NAPI is always enabled when an interrupt occurs, and polling to handle the interrupt can commence immediately. The channel STOPPING flag ensures the polling function won't re-enable the completion interrupt while we are stopping. Fixes: 650d1603825d8 ("soc: qcom: ipa: the generic software interface") Signed-off-by: Alex Elder --- drivers/net/ipa/gsi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c index 7e7629902911e..9bde6d02b1cd6 100644 --- a/drivers/net/ipa/gsi.c +++ b/drivers/net/ipa/gsi.c @@ -743,21 +743,21 @@ static void gsi_channel_freeze(struct gsi_channel *channel) set_bit(GSI_CHANNEL_FLAG_STOPPING, channel->flags); smp_mb__after_atomic(); /* Ensure gsi_channel_poll() sees new value */ - napi_disable(&channel->napi); - gsi_irq_ieob_disable(channel->gsi, channel->evt_ring_id); + + napi_disable(&channel->napi); } /* Allow transactions to be used on the channel again. */ static void gsi_channel_thaw(struct gsi_channel *channel) { - gsi_irq_ieob_enable(channel->gsi, channel->evt_ring_id); - /* Allow the NAPI poll loop to re-enable interrupts again */ clear_bit(GSI_CHANNEL_FLAG_STOPPING, channel->flags); smp_mb__after_atomic(); /* Ensure gsi_channel_poll() sees new value */ napi_enable(&channel->napi); + + gsi_irq_ieob_enable(channel->gsi, channel->evt_ring_id); } /* Program a channel for use */ -- 2.20.1