Re: [PATCH 2/4] PCI: add functionality for resizing resources v3

From: Christian KÃnig
Date: Tue May 02 2017 - 11:52:02 EST

Am 26.04.2017 um 19:00 schrieb Andy Shevchenko:
On Tue, Apr 25, 2017 at 4:19 PM, Christian KÃnig
<deathsimple@xxxxxxxxxxx> wrote:
From: Christian KÃnig <christian.koenig@xxxxxxx>

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.
+int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
+ const unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |

Redundant, but also a reminder to myself that I wanted to ask something about that.

This type_mask is used already three times in this file, shouldn't we add a define for that?

+ list_for_each_entry(dev_res, &saved, list) {
+ /* Skip the bridge we just assigned resources for. */
+ if (bridge == dev_res->dev)
+ continue;
+ bridge = dev_res->dev;
+ pci_setup_bridge(bridge->subordinate);
+ }
+ free_list(&saved);
+ free_list(&failed);
+ return ret;
You might re-use two lines with below, but perhaps better to show
which case returns 0 explicitly and drop assignment ret = 0 above.

Good point, but actually the free_list(&failed) is superfluous here since when the failed list isn't empty we end up in the cleanup path.

Going to fix all other comments in the next version.