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SubjectRe: [PATCH v9 4/8] PCI/sysfs: Allow userspace to query and set device reset mechanism
On 21/07/11 04:51PM, Raphael Norwitz wrote:
> On Mon, Jul 05, 2021 at 07:51:34PM +0530, Amey Narkhede wrote:
> > Add reset_method sysfs attribute to enable user to query and set user
> > preferred device reset methods and their ordering.
> >
> > Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
>
> Just some spacing NITs.
>
> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
>
> > ---
> > Documentation/ABI/testing/sysfs-bus-pci | 19 +++++
> > drivers/pci/pci-sysfs.c | 103 ++++++++++++++++++++++++
> > 2 files changed, 122 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
> > index ef00fada2..43f4e33c7 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-pci
> > +++ b/Documentation/ABI/testing/sysfs-bus-pci
> > @@ -121,6 +121,25 @@ Description:
> > child buses, and re-discover devices removed earlier
> > from this part of the device tree.
> >
> > +What: /sys/bus/pci/devices/.../reset_method
> > +Date: March 2021
> > +Contact: Amey Narkhede <ameynarkhede03@gmail.com>
> > +Description:
> > + Some devices allow an individual function to be reset
> > + without affecting other functions in the same slot.
> > +
> > + For devices that have this support, a file named
> > + reset_method will be present in sysfs. Initially reading
> > + this file will give names of the device supported reset
> > + methods and their ordering. After write, this file will
> > + give names and ordering of currently enabled reset methods.
> > + Writing the name or comma separated list of names of any of
> > + the device supported reset methods to this file will set
> > + the reset methods and their ordering to be used when
> > + resetting the device. Writing empty string to this file
> > + will disable ability to reset the device and writing
> > + "default" will return to the original value.
> > +
> > What: /sys/bus/pci/devices/.../reset
> > Date: July 2009
> > Contact: Michael S. Tsirkin <mst@redhat.com>
> > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> > index 316f70c3e..8a740e211 100644
> > --- a/drivers/pci/pci-sysfs.c
> > +++ b/drivers/pci/pci-sysfs.c
> > @@ -1334,6 +1334,108 @@ static const struct attribute_group pci_dev_rom_attr_group = {
> > .is_bin_visible = pci_dev_rom_attr_is_visible,
> > };
> >
> > +static ssize_t reset_method_show(struct device *dev,
>
> Nit: spaces on the following two lines. "struct device_attribute *attr"
> and "char *buf" should be in line with "struct device *dev"
>
Not sure what happened when creating the patches but on my editor spaces
seems to consistent as you suggested here. For some reason git
format-patch is acting weird.

Thanks,
Amey
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct pci_dev *pdev = to_pci_dev(dev);
> > + ssize_t len = 0;
> > + int i, idx;
> > +
> > + for (i = 0; i < PCI_NUM_RESET_METHODS; i++) {
> > + idx = pdev->reset_methods[i];
> > + if (!idx)
> > + break;
> > +
> > + len += sysfs_emit_at(buf, len, "%s%s", len ? "," : "",
> > + pci_reset_fn_methods[idx].name);
> > + }
> > +
> > + if (len)
> > + len += sysfs_emit_at(buf, len, "\n");
> > +
> > + return len;
> > +}
> > +
> > +static ssize_t reset_method_store(struct device *dev,
>
> Nit: spaces on the following two lines
>
> > + struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + struct pci_dev *pdev = to_pci_dev(dev);
> > + int n = 0;
> > + char *name, *options = NULL;
> > + u8 reset_methods[PCI_NUM_RESET_METHODS] = { 0 };
> > +
> > + if (count >= (PAGE_SIZE - 1))
> > + return -EINVAL;
> > +
> > + if (sysfs_streq(buf, "")) {
> > + pci_warn(pdev, "All device reset methods disabled by user");
> > + goto set_reset_methods;
> > + }
> > +
> > + if (sysfs_streq(buf, "default")) {
> > + pci_init_reset_methods(pdev);
> > + return count;
> > + }
> > +
> > + options = kstrndup(buf, count, GFP_KERNEL);
> > + if (!options)
> > + return -ENOMEM;
> > +
> > + while ((name = strsep(&options, ",")) != NULL) {
> > + int i;
> > +
> > + if (sysfs_streq(name, ""))
> > + continue;
> > +
> > + name = strim(name);
> > +
> > + for (i = 1; i < PCI_NUM_RESET_METHODS; i++) {
> > + if (sysfs_streq(name, pci_reset_fn_methods[i].name) &&
> > + !pci_reset_fn_methods[i].reset_fn(pdev, 1)) {
> > + reset_methods[n++] = i;
> > + break;
> > + }
> > + }
> > +
> > + if (i == PCI_NUM_RESET_METHODS) {
> > + kfree(options);
> > + return -EINVAL;
> > + }
> > + }
> > +
> > + if (!pci_reset_fn_methods[1].reset_fn(pdev, 1) && reset_methods[0] != 1)
> > + pci_warn(pdev, "Device specific reset disabled/de-prioritized by user");
> > +
> > +set_reset_methods:
> > + memcpy(pdev->reset_methods, reset_methods, sizeof(reset_methods));
> > + kfree(options);
> > + return count;
> > +}
> > +static DEVICE_ATTR_RW(reset_method);
> > +
> > +static struct attribute *pci_dev_reset_method_attrs[] = {
> > + &dev_attr_reset_method.attr,
> > + NULL,
> > +};
> > +
> > +static umode_t pci_dev_reset_method_attr_is_visible(struct kobject *kobj,
>
> Nit: ditto - spacing.
>
> > + struct attribute *a, int n)
> > +{
> > + struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> > +
> > + if (!pci_reset_supported(pdev))
> > + return 0;
> > +
> > + return a->mode;
> > +}
> > +
> > +static const struct attribute_group pci_dev_reset_method_attr_group = {
> > + .attrs = pci_dev_reset_method_attrs,
> > + .is_visible = pci_dev_reset_method_attr_is_visible,
> > +};
> > +
> > static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
>
> Nit: spacing following line.
>
> > const char *buf, size_t count)
> > {
> > @@ -1491,6 +1593,7 @@ const struct attribute_group *pci_dev_groups[] = {
> > &pci_dev_config_attr_group,
> > &pci_dev_rom_attr_group,
> > &pci_dev_reset_attr_group,
> > + &pci_dev_reset_method_attr_group,
> > &pci_dev_vpd_attr_group,
> > #ifdef CONFIG_DMI
> > &pci_dev_smbios_attr_group,
> > --
> > 2.32.0
> >
> >

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