| Message ID | 20240706-device_for_each_child_node-available-v1-6-8a3f7615e41c@gmail.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | use device_for_each_child_node() to access device child nodes | expand |
On Sat, 06 Jul 2024 17:23:38 +0200 Javier Carrasco <javier.carrasco.cruz@gmail.com> 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, > and the socped version of the macro can be used to automatically > 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 <javier.carrasco.cruz@gmail.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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" ? > 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 <javier.carrasco.cruz@gmail.com> > --- > 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.
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 <javier.carrasco.cruz@gmail.com> >> --- >> 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
On Mon, Jul 29, 2024 at 11:23:47AM +0200, Javier Carrasco wrote: > 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? If you're referring to the one before the clk_disable_unprepare() calls, it's only slightly suspicious: These clocks are setup in a: if (dev_of_node(&pdev->dev)) { ... } block, so they're only setup if we have device tree. So, avoiding it for ACPI is entirely reasonable. However, we also have software nodes as well, so the test should be: if (!dev_of_node(&pdev->dev)) return; to match what the probe function is doing. Thanks.
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]);
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, and the socped version of the macro can be used to automatically 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 <javier.carrasco.cruz@gmail.com> --- drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)