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Message-ID: <ZGMiE1ByArIr8ARB@nanopsycho>
Date: Tue, 16 May 2023 08:26:27 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: "Kubalewski, Arkadiusz" <arkadiusz.kubalewski@...el.com>
Cc: Vadim Fedorenko <vadfed@...a.com>, Jakub Kicinski <kuba@...nel.org>,
Jonathan Lemon <jonathan.lemon@...il.com>,
Paolo Abeni <pabeni@...hat.com>,
"Olech, Milena" <milena.olech@...el.com>,
"Michalik, Michal" <michal.michalik@...el.com>,
"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
poros <poros@...hat.com>, mschmidt <mschmidt@...hat.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>
Subject: Re: [RFC PATCH v7 5/8] ice: implement dpll interface to control cgu
Tue, May 16, 2023 at 12:07:57AM CEST, arkadiusz.kubalewski@...el.com wrote:
>>From: Jiri Pirko <jiri@...nulli.us>
>>Sent: Wednesday, May 3, 2023 2:19 PM
>>
>>Fri, Apr 28, 2023 at 02:20:06AM CEST, vadfed@...a.com wrote:
>>>From: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>
[...]
>>>+ * ice_dpll_frequency_set - wrapper for pin callback for set frequency
>>>+ * @pin: pointer to a pin
>>>+ * @pin_priv: private data pointer passed on pin registration
>>>+ * @dpll: pointer to dpll
>>>+ * @frequency: frequency to be set
>>>+ * @extack: error reporting
>>>+ * @pin_type: type of pin being configured
>>>+ *
>>>+ * Wraps internal set frequency command on a pin.
>>>+ *
>>>+ * Return:
>>>+ * * 0 - success
>>>+ * * negative - error pin not found or couldn't set in hw */ static
>>>+int ice_dpll_frequency_set(const struct dpll_pin *pin, void *pin_priv,
>>>+ const struct dpll_device *dpll,
>>>+ const u32 frequency,
>>>+ struct netlink_ext_ack *extack,
>>>+ const enum ice_dpll_pin_type pin_type) {
>>>+ struct ice_pf *pf = pin_priv;
>>>+ struct ice_dpll_pin *p;
>>>+ int ret = -EINVAL;
>>>+
>>>+ if (!pf)
>>>+ return ret;
>>>+ if (ice_dpll_cb_lock(pf))
>>>+ return -EBUSY;
>>>+ p = ice_find_pin(pf, pin, pin_type);
>>
>>This does not make any sense to me. You should avoid the lookups and remove
>>ice_find_pin() function entirely. The purpose of having pin_priv is to
>>carry the struct ice_dpll_pin * directly. You should pass it down during
>>pin register.
>>
>>pf pointer is stored in dpll_priv.
>>
>
>In this case dpll_priv is not passed, so cannot use it.
It should be passed. In general to every op where *dpll is passed, the
dpll_priv pointer should be passed along. Please, fix this.
>But in general it makes sense I will hold pf inside of ice_dpll_pin
>and fix this.
Nope, just use dpll_priv. That's why we have it.
[...]
>>>+/**
>>>+ * ice_dpll_pin_state_set - set pin's state on dpll
>>>+ * @dpll: dpll being configured
>>>+ * @pin: pointer to a pin
>>>+ * @pin_priv: private data pointer passed on pin registration
>>>+ * @state: state of pin to be set
>>>+ * @extack: error reporting
>>>+ * @pin_type: type of a pin
>>>+ *
>>>+ * Set pin state on a pin.
>>>+ *
>>>+ * Return:
>>>+ * * 0 - OK or no change required
>>>+ * * negative - error
>>>+ */
>>>+static int
>>>+ice_dpll_pin_state_set(const struct dpll_device *dpll,
>>>+ const struct dpll_pin *pin, void *pin_priv,
>>>+ const enum dpll_pin_state state,
>>
>>Why you use const with enums?
>>
>
>Just show usage intention explicitly.
Does not make any sense what so ever. Please avoid it.
>>>+static int ice_dpll_rclk_state_on_pin_get(const struct dpll_pin *pin,
>>>+ void *pin_priv,
>>>+ const struct dpll_pin *parent_pin,
>>>+ enum dpll_pin_state *state,
>>>+ struct netlink_ext_ack *extack) {
>>>+ struct ice_pf *pf = pin_priv;
>>>+ u32 parent_idx, hw_idx = ICE_DPLL_PIN_IDX_INVALID, i;
>>
>>Reverse christmas tree ordering please.
>
>Fixed.
>
>>
>>
>>>+ struct ice_dpll_pin *p;
>>>+ int ret = -EFAULT;
>>>+
>>>+ if (!pf)
>>
>>How exacly this can happen. My wild guess is it can't. Don't do such
>>pointless checks please, confuses the reader.
>>
>
>>From driver perspective the pf pointer value is given by external entity,
>why shouldn't it be valdiated?
What? You pass it during register, you get it back here. Nothing to
check. Please drop it. Non-sense checks like this have no place in
kernel, they only confuse reader as he/she assumes it is a valid case.
[...]
>>
>>
>>>+ pins[i].pin = NULL;
>>>+ return -ENOMEM;
>>>+ }
>>>+ if (cgu) {
>>>+ ret = dpll_pin_register(pf->dplls.eec.dpll,
>>>+ pins[i].pin,
>>>+ ops, pf, NULL);
>>>+ if (ret)
>>>+ return ret;
>>>+ ret = dpll_pin_register(pf->dplls.pps.dpll,
>>>+ pins[i].pin,
>>>+ ops, pf, NULL);
>>>+ if (ret)
>>>+ return ret;
>>
>>You have to call dpll_pin_unregister(pf->dplls.eec.dpll, pins[i].pin, ..)
>>here.
>>
>
>No, in case of error, the caller releases everything ice_dpll_release_all(..).
How does ice_dpll_release_all() where you failed? If you need to
unregister one or both or none? I know that in ice you have odd ways to
handle error paths in general, but this one clearly seems to be broken.
>
>>
>>>+ }
>>>+ }
>>>+ if (cgu) {
>>>+ ops = &ice_dpll_output_ops;
>>>+ pins = pf->dplls.outputs;
>>>+ for (i = 0; i < pf->dplls.num_outputs; i++) {
>>>+ pins[i].pin = dpll_pin_get(pf->dplls.clock_id,
>>>+ i + pf->dplls.num_inputs,
>>>+ THIS_MODULE, &pins[i].prop);
>>>+ if (IS_ERR_OR_NULL(pins[i].pin)) {
>>>+ pins[i].pin = NULL;
>>>+ return -ENOMEM;
>>
>>Don't make up error values when you get them from the function you call:
>> return PTR_ERR(pins[i].pin);
>
>Fixed.
>
>>
>>>+ }
>>>+ ret = dpll_pin_register(pf->dplls.eec.dpll, pins[i].pin,
>>>+ ops, pf, NULL);
>>>+ if (ret)
>>>+ return ret;
>>>+ ret = dpll_pin_register(pf->dplls.pps.dpll, pins[i].pin,
>>>+ ops, pf, NULL);
>>>+ if (ret)
>>>+ return ret;
>>
>>You have to call dpll_pin_unregister(pf->dplls.eec.dpll, pins[i].pin, ..)
>>here.
>>
>
>As above, in case of error, the caller releases everything.
As above, I don't think it works.
[...]
>>>+ }
>>>+
>>>+ if (cgu) {
>>>+ ret = dpll_device_register(pf->dplls.eec.dpll, DPLL_TYPE_EEC,
>>>+ &ice_dpll_ops, pf, dev);
>>>+ if (ret)
>>>+ goto put_pps;
>>>+ ret = dpll_device_register(pf->dplls.pps.dpll, DPLL_TYPE_PPS,
>>>+ &ice_dpll_ops, pf, dev);
>>>+ if (ret)
>>
>>You are missing call to dpll_device_unregister(pf->dplls.eec.dpll,
>>DPLL_TYPE_EEC here. Fix the error path.
>>
>
>The caller shall do the clean up, but yeah will fix this as here clean up
>is not expected.
:) Just make your error paths obvious and easy to follow to not to
confuse anybody, you included.
>
>>
>>>+ goto put_pps;
>>>+ }
>>>+
>>>+ return 0;
>>>+
>>>+put_pps:
>>>+ dpll_device_put(pf->dplls.pps.dpll);
>>>+ pf->dplls.pps.dpll = NULL;
>>>+put_eec:
>>>+ dpll_device_put(pf->dplls.eec.dpll);
>>>+ pf->dplls.eec.dpll = NULL;
>>>+
>>>+ return ret;
>>>+}
[...]
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