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SubjectRe: [PATCH 2/4] PCI: add functionality for resizing resources v2
On Mon, Mar 13, 2017 at 2:41 PM, Christian König
<deathsimple@vodafone.de> wrote:
> From: Christian König <christian.koenig@amd.com>
>
> This allows device drivers to request resizing their BARs.
>
> The function only tries to reprogram the windows of the bridge directly above
> the requesting device and only the BAR of the same type (usually mem, 64bit,
> prefetchable). This is done to make sure not to disturb other drivers by
> changing the BARs of their devices.
>
> If reprogramming the bridge BAR fails the old status is restored and -ENOSPC
> returned to the calling device driver.

Some style comments.

> v2: rebase on changes in rbar support

This kind of comments usually goes after --- delimiter below.

> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---

...here.

> +int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
> +{
> + const unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
> + IORESOURCE_PREFETCH | IORESOURCE_MEM_64;
> +
> + struct resource saved;
> + LIST_HEAD(add_list);
> + LIST_HEAD(fail_head);

> + struct pci_dev_resource *fail_res;

Perhaps move before definition of 'saved'?

> + unsigned i;
> + int ret = 0;
> +
> + /* Release all children from the matching bridge resource */
> + for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END; ++i) {
> + struct resource *res = &bridge->resource[i];
> +


> + if ((res->flags & type_mask) != (type & type_mask))

IIUC it would be
if ((res->flags ^ type) & type_mask)

(I consider 'diff' as XOR operation is more understandable, but it's up to you)

> + continue;

> + /* restore size and flags */
> + list_for_each_entry(fail_res, &fail_head, list) {
> + struct resource *res = fail_res->res;
> +
> + res->start = fail_res->start;
> + res->end = fail_res->end;
> + res->flags = fail_res->flags;
> + }
> +
> + /* Revert to the old configuration */
> + if (!list_empty(&fail_head)) {
> + struct resource *res = &bridge->resource[i];
> +

> + res->start = saved.start;
> + res->end = saved.end;
> + res->flags = saved.flags;

Would
*res = saved;
work?

> +int pci_resize_resource(struct pci_dev *dev, int resno, int size)
> +{
> + struct resource *res = dev->resource + resno;
> + u32 sizes = pci_rbar_get_possible_sizes(dev, resno);
> + int old = pci_rbar_get_current_size(dev, resno);
> + u64 bytes = 1ULL << (size + 20);
> + int ret = 0;
> +

I would put
sizes = pci_rbar_get_possible_sizes(dev, resno);
here

> + if (!sizes)
> + return -ENOTSUPP;
> +
> + if (!(sizes & (1 << size)))

BIT(size) ?

> + return -EINVAL;
> +

and
old = pci_rbar_get_current_size(dev, resno);
here

> + if (old < 0)
> + return old;

> +error_resize:
> + pci_rbar_set_size(dev, resno, old);
> + res->end = res->start + (1ULL << (old + 20)) - 1;

BIT_ULL(old + 20) ?

--
With Best Regards,
Andy Shevchenko

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