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[73.185.129.58]) by smtp.gmail.com with ESMTPSA id f29sm16328385ilg.3.2020.12.22.10.00.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Dec 2020 10:00:17 -0800 (PST) From: Alex Elder To: davem@davemloft.net, kuba@kernel.org Cc: evgreen@chromium.org, cpratapa@codeaurora.org, bjorn.andersson@linaro.org, subashab@codeaurora.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 2/3] net: ipa: use state to determine channel command success Date: Tue, 22 Dec 2020 12:00:11 -0600 Message-Id: <20201222180012.22489-3-elder@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201222180012.22489-1-elder@linaro.org> References: <20201222180012.22489-1-elder@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The result of issuing a channel control command should be that the channel changes state. If enabled, a completion interrupt signals that the channel state has changed. This interrupt is enabled by gsi_channel_command() and disabled again after the command has completed (or we time out). There is a window of time--after the completion interrupt is disabled but before the channel state is read--during which the command could complete successfully without interrupting. This would cause the channel to transition to the desired new state. So whether a channel command ends via completion interrupt or timeout, we can consider the command successful if the channel has entered the desired state (and a failure if it has not, regardless of the cause). Fixes: d6c9e3f506ae8 ("net: ipa: only enable generic command completion IRQ when needed"); Signed-off-by: Alex Elder Reported-by: kernel test robot --- drivers/net/ipa/gsi.c | 43 ++++++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 21 deletions(-) diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c index 4aee60d62ab09..4f0e791764237 100644 --- a/drivers/net/ipa/gsi.c +++ b/drivers/net/ipa/gsi.c @@ -505,15 +505,15 @@ static int gsi_channel_alloc_command(struct gsi *gsi, u32 channel_id) ret = gsi_channel_command(channel, GSI_CH_ALLOCATE); - /* Channel state will normally have been updated */ + /* If successful the channel state will have changed */ state = gsi_channel_state(channel); - if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED) { - dev_err(dev, "channel %u bad state %u after alloc\n", - channel_id, state); - ret = -EIO; - } + if (state == GSI_CHANNEL_STATE_ALLOCATED) + return 0; - return ret; + dev_err(dev, "channel %u bad state %u after alloc\n", + channel_id, state); + + return -EIO; } /* Start an ALLOCATED channel */ @@ -533,15 +533,15 @@ static int gsi_channel_start_command(struct gsi_channel *channel) ret = gsi_channel_command(channel, GSI_CH_START); - /* Channel state will normally have been updated */ + /* If successful the channel state will have changed */ state = gsi_channel_state(channel); - if (!ret && state != GSI_CHANNEL_STATE_STARTED) { - dev_err(dev, "channel %u bad state %u after start\n", - gsi_channel_id(channel), state); - ret = -EIO; - } + if (state == GSI_CHANNEL_STATE_STARTED) + return 0; - return ret; + dev_err(dev, "channel %u bad state %u after start\n", + gsi_channel_id(channel), state); + + return -EIO; } /* Stop a GSI channel in STARTED state */ @@ -568,10 +568,10 @@ static int gsi_channel_stop_command(struct gsi_channel *channel) ret = gsi_channel_command(channel, GSI_CH_STOP); - /* Channel state will normally have been updated */ + /* If successful the channel state will have changed */ state = gsi_channel_state(channel); - if (ret || state == GSI_CHANNEL_STATE_STOPPED) - return ret; + if (state == GSI_CHANNEL_STATE_STOPPED) + return 0; /* We may have to try again if stop is in progress */ if (state == GSI_CHANNEL_STATE_STOP_IN_PROC) @@ -604,9 +604,9 @@ static void gsi_channel_reset_command(struct gsi_channel *channel) ret = gsi_channel_command(channel, GSI_CH_RESET); - /* Channel state will normally have been updated */ + /* If successful the channel state will have changed */ state = gsi_channel_state(channel); - if (!ret && state != GSI_CHANNEL_STATE_ALLOCATED) + if (state != GSI_CHANNEL_STATE_ALLOCATED) dev_err(dev, "channel %u bad state %u after reset\n", gsi_channel_id(channel), state); } @@ -628,9 +628,10 @@ static void gsi_channel_de_alloc_command(struct gsi *gsi, u32 channel_id) ret = gsi_channel_command(channel, GSI_CH_DE_ALLOC); - /* Channel state will normally have been updated */ + /* If successful the channel state will have changed */ state = gsi_channel_state(channel); - if (!ret && state != GSI_CHANNEL_STATE_NOT_ALLOCATED) + + if (state != GSI_CHANNEL_STATE_NOT_ALLOCATED) dev_err(dev, "channel %u bad state %u after dealloc\n", channel_id, state); }