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[91.118.163.37]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5ac631b0491sm5493664a12.8.2024.07.29.02.23.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 29 Jul 2024 02:23:48 -0700 (PDT) Message-ID: Date: Mon, 29 Jul 2024 11:23:47 +0200 Precedence: bulk X-Mailing-List: linux-leds@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6/6] net: mvpp2: use device_for_each_child_node() to access device child nodes To: "Russell King (Oracle)" Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Andy Shevchenko , Jonathan Cameron , Rob Herring , Daniel Scally , Heikki Krogerus , Sakari Ailus , Jean Delvare , Guenter Roeck , Pavel Machek , Lee Jones , Marcin Wojtas , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-leds@vger.kernel.org, netdev@vger.kernel.org References: <20240706-device_for_each_child_node-available-v1-0-8a3f7615e41c@gmail.com> <20240706-device_for_each_child_node-available-v1-6-8a3f7615e41c@gmail.com> Content-Language: en-US, de-AT From: Javier Carrasco In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 29/07/2024 10:23, Russell King (Oracle) wrote: > On Sat, Jul 06, 2024 at 05:23:38PM +0200, Javier Carrasco wrote: >> The iterated nodes are direct children of the device node, and the >> `device_for_each_child_node()` macro accounts for child node >> availability. >> >> `fwnode_for_each_available_child_node()` is meant to access the child >> nodes of an fwnode, and therefore not direct child nodes of the device >> node. >> >> The child nodes within mvpp2_probe are not accessed outside the lopps, > > "lopps" ? > >> and the socped version of the macro can be used to automatically > > "socped" ? > I'll fix the typos for v3. >> decrement the refcount on early exits. >> >> Use `device_for_each_child_node()` and its scoped variant to indicate >> device's direct child nodes. >> >> Signed-off-by: Javier Carrasco >> --- >> drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 13 ++++--------- >> 1 file changed, 4 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c >> index 9adf4301c9b1..97f1faab6f28 100644 >> --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c >> +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c >> @@ -7417,8 +7417,6 @@ static int mvpp2_get_sram(struct platform_device *pdev, >> >> static int mvpp2_probe(struct platform_device *pdev) >> { >> - struct fwnode_handle *fwnode = pdev->dev.fwnode; >> - struct fwnode_handle *port_fwnode; >> struct mvpp2 *priv; >> struct resource *res; >> void __iomem *base; >> @@ -7591,7 +7589,7 @@ static int mvpp2_probe(struct platform_device *pdev) >> } >> >> /* Map DTS-active ports. Should be done before FIFO mvpp2_init */ >> - fwnode_for_each_available_child_node(fwnode, port_fwnode) { >> + device_for_each_child_node_scoped(&pdev->dev, port_fwnode) { >> if (!fwnode_property_read_u32(port_fwnode, "port-id", &i)) >> priv->port_map |= BIT(i); >> } >> @@ -7614,7 +7612,7 @@ static int mvpp2_probe(struct platform_device *pdev) >> goto err_axi_clk; >> >> /* Initialize ports */ >> - fwnode_for_each_available_child_node(fwnode, port_fwnode) { >> + device_for_each_child_node_scoped(&pdev->dev, port_fwnode) { >> err = mvpp2_port_probe(pdev, port_fwnode, priv); >> if (err < 0) >> goto err_port_probe; >> @@ -7653,10 +7651,8 @@ static int mvpp2_probe(struct platform_device *pdev) >> return 0; >> >> err_port_probe: >> - fwnode_handle_put(port_fwnode); >> - >> i = 0; >> - fwnode_for_each_available_child_node(fwnode, port_fwnode) { >> + device_for_each_child_node_scoped(&pdev->dev, port_fwnode) { >> if (priv->port_list[i]) >> mvpp2_port_remove(priv->port_list[i]); >> i++; >> @@ -7677,13 +7673,12 @@ static int mvpp2_probe(struct platform_device *pdev) >> static void mvpp2_remove(struct platform_device *pdev) >> { >> struct mvpp2 *priv = platform_get_drvdata(pdev); >> - struct fwnode_handle *fwnode = pdev->dev.fwnode; >> int i = 0, poolnum = MVPP2_BM_POOLS_NUM; >> struct fwnode_handle *port_fwnode; >> >> mvpp2_dbgfs_cleanup(priv); >> >> - fwnode_for_each_available_child_node(fwnode, port_fwnode) { >> + device_for_each_child_node(&pdev->dev, port_fwnode) { >> if (priv->port_list[i]) { >> mutex_destroy(&priv->port_list[i]->gather_stats_lock); >> mvpp2_port_remove(priv->port_list[i]); > > This loop is just silly. There is no need to iterate the child nodes. > port_fwnode is not used, and the loop boils down to: > > for (i = 0; i < priv->port_count; i++) { > mutex_destroy(&priv->port_list[i]->gather_stats_lock); > mvpp2_port_remove(priv->port_list[i]); > } > > Not only is walking the child nodes not necessary, but checking whether > the pointer is NULL is also unnecessary. mvpp2_port_probe() populates > the array using: > > priv->port_list[priv->port_count++] = port; > > and "port" can not be NULL here, so we're guaranteed that all port_list > entries for 0..priv->port_count will be non-NULL, and the driver makes > this assumption in multiple places. > > In fact, I'd say that using fwnode_for_each_available_child_node() or > device_for_each_child_node() is buggy here if the availability of the > children change - it could leave ports not cleaned up. > I will add your suggestions in a separate patch with the corresponding Suggested-by: tag. In that case, and taking into account that the pointer check is unnecessary, the loop after a goto err_port_probe will turn into this: err_port_probe: for (i = 0; i < priv->port_count; i++) mvpp2_port_remove(priv->port_list[i]); and the loop in mvpp2_remove() will be exactly the one you suggested. Apart from that, there is a suspicious check towards the end of the same function: if (is_acpi_node(port_fwnode)) return; At the point it is called in the current implementation, port_fwnode could have been cleaned. And after removing the loop, it is simply uninitialized. Was that meant to be pdev->dev->fwnode? Thanks and best regards, Javier Carrasco