[PATCH] PCI: vmd: guard device addition and removal

You-Sheng Yang (vicamo)
2023-03-13T17:38:35Z

VMD may fail to create sysfs entries while `pci_rescan_bus()` called in
some other drivers like t7xx wwan driver:

sysfs: cannot create duplicate filename '/devices/.../resource0'
Call Trace:
<TASK>
sysfs_warn_dup.cold+0x17/0x34
sysfs_add_bin_file_mode_ns+0xc0/0xf0
sysfs_create_bin_file+0x6d/0xb0
pci_create_attr+0x117/0x260
pci_create_resource_files+0x6b/0x150
pci_create_sysfs_dev_files+0x18/0x30
pci_bus_add_device+0x30/0x80
pci_bus_add_devices+0x31/0x80
pci_bus_add_devices+0x5b/0x80
vmd_enable_domain.constprop.0+0x6b7/0x880 [vmd]
vmd_probe+0x16d/0x193 [vmd]

Fixes: 185a383ada2e ("x86/PCI: Add driver for Intel Volume Management Device (VMD)")
Signed-off-by: You-Sheng Yang (vicamo) <vicamo.yang@canonical.com>
---
drivers/pci/controller/vmd.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 769eedeb8802..f050991bd1e9 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -838,9 +838,13 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
pci_add_resource_offset(&resources, &vmd->resources[1], offset[0]);
pci_add_resource_offset(&resources, &vmd->resources[2], offset[1]);

+ pci_lock_rescan_remove();
+
vmd->bus = pci_create_root_bus(&vmd->dev->dev, vmd->busn_start,
&vmd_ops, sd, &resources);
if (!vmd->bus) {
+ pci_unlock_rescan_remove();
+
pci_free_resource_list(&resources);
vmd_remove_irq_domain(vmd);
return -ENODEV;
@@ -893,6 +897,8 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)

vmd_acpi_end();

+ pci_unlock_rescan_remove();
+
WARN(sysfs_create_link(&vmd->dev->dev.kobj, &vmd->bus->dev.kobj,
"domain"), "Can't create symlink to domain\n");
return 0;
--
2.39.2