Re: [PATCH 13/15] PCI/ASPM: use permission-specific DEVICE_ATTR variants

Bjorn Helgaas
2016-11-14T21:40:48Z

On Sat, Oct 29, 2016 at 09:37:07PM +0200, Julia Lawall wrote:
> Use DEVICE_ATTR_RW for read-write attributes. This simplifies the
> source code, improves readbility, and reduces the chance of
> inconsistencies.
>
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @rw@
> declarer name DEVICE_ATTR;
> identifier x,x_show,x_store;
> @@
>
> DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);
>
> @script:ocaml@
> x << rw.x;
> x_show << rw.x_show;
> x_store << rw.x_store;
> @@
>
> if not (x^"_show" = x_show && x^"_store" = x_store)
> then Coccilib.include_match false
>
> @@
> declarer name DEVICE_ATTR_RW;
> identifier rw.x,rw.x_show,rw.x_store;
> @@
>
> - DEVICE_ATTR(x, \(0644\|S_IRUGO|S_IWUSR\), x_show, x_store);
> + DEVICE_ATTR_RW(x);
> // </smpl>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

I applied this to pci/aspm to follow the herd, although it looks
pretty similar to the ill-fated "Replace numeric parameter like 0444
with macro" series (http://lwn.net/Articles/696229/). Maybe this is
different because everybody except me knows what ATTR_RW means? To
me, "0644" contained more information than "_RW" does.

I do certainly like the removal of the "_show" and "_store"
redundancy.

> ---
> drivers/pci/pcie/aspm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> index 0ec649d..3b14d9e 100644
> --- a/drivers/pci/pcie/aspm.c
> +++ b/drivers/pci/pcie/aspm.c
> @@ -886,8 +886,8 @@ static ssize_t clk_ctl_store(struct device *dev,
> return n;
> }
>
> -static DEVICE_ATTR(link_state, 0644, link_state_show, link_state_store);
> -static DEVICE_ATTR(clk_ctl, 0644, clk_ctl_show, clk_ctl_store);
> +static DEVICE_ATTR_RW(link_state);
> +static DEVICE_ATTR_RW(clk_ctl);
>
> static char power_group[] = "power";
> void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
>