From d09ddd8190fbdc07696bf34b548ae15aa1816714 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@kernel.org>
Date: Tue, 21 Apr 2020 18:22:56 +0200
Subject: [PATCH] PCI: Allow pci_resize_resource() for devices on root bus
Mime-version: 1.0
Content-type: text/plain; charset=UTF-8
Content-transfer-encoding: 8bit
Git-commit: d09ddd8190fbdc07696bf34b548ae15aa1816714
Patch-mainline: v5.8-rc1
References: bsc#1051510
When resizing a BAR, pci_reassign_bridge_resources() is invoked to bring
the bridge windows of parent bridges in line with the new BAR assignment.
This assumes the device whose BAR is being resized lives on a subordinate
bus, but this is not necessarily the case. A device may live on the root
bus, in which case dev->bus->self is NULL, and passing a NULL pci_dev
pointer to pci_reassign_bridge_resources() will cause it to crash.
So let's make the call to pci_reassign_bridge_resources() conditional on
whether dev->bus->self is non-NULL in the first place.
Fixes: 8bb705e3e79d84e7 ("PCI: Add pci_resize_resource() for resizing BARs")
Link: https://lore.kernel.org/r/20200421162256.26887-1-ardb@kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/pci/setup-res.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index d8ca40a97693..d21fa04fa44d 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -439,10 +439,11 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size)
res->end = res->start + pci_rebar_size_to_bytes(size) - 1;
/* Check if the new config works by trying to assign everything. */
- ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
- if (ret)
- goto error_resize;
-
+ if (dev->bus->self) {
+ ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
+ if (ret)
+ goto error_resize;
+ }
return 0;
error_resize:
--
2.16.4