Wire up the can_remove() callback, such that pci drivers can implement their own version of it.

Cc: stable@vger.kernel.org Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com --- drivers/pci/pci-driver.c | 12 ++++++++++++ include/linux/pci.h | 5 +++++ 2 files changed, 17 insertions(+)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 51ec9e7e784f..8aae484c5494 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -466,6 +466,17 @@ static int pci_device_probe(struct device *dev) return error; }

+static bool pci_device_can_remove(struct device *dev) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + struct pci_driver *drv = pci_dev->driver; + + if (drv->can_remove) + return drv->can_remove(pci_dev); + + return true; +} + static void pci_device_remove(struct device *dev) { struct pci_dev *pci_dev = to_pci_dev(dev); @@ -1680,6 +1691,7 @@ struct bus_type pci_bus_type = { .match = pci_bus_match, .uevent = pci_uevent, .probe = pci_device_probe, + .can_remove = pci_device_can_remove, .remove = pci_device_remove, .shutdown = pci_device_shutdown, .dev_groups = pci_dev_groups, diff --git a/include/linux/pci.h b/include/linux/pci.h index add9368e6314..95276f44b23b 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -902,6 +902,10 @@ struct module; * (negative number) otherwise. * The probe function always gets called from process * context, so it can sleep. + * @can_remove: The can_remove() function gets called during driver + * deregistration to determine if remove() can be called. + * The probe function always gets called from process + * context, so it can sleep. * @remove: The remove() function gets called whenever a device * being handled by this driver is removed (either during * deregistration of the driver or when it's manually @@ -943,6 +947,7 @@ struct pci_driver { const char *name; const struct pci_device_id *id_table; /* Must be non-NULL for probe to be called */ int (*probe)(struct pci_dev *dev, const struct pci_device_id *id); /* New device inserted */ + bool (*can_remove)(struct pci_dev *dev); void (*remove)(struct pci_dev *dev); /* Device removed (NULL if not a hot-plug capable driver) */ int (*suspend)(struct pci_dev *dev, pm_message_t state); /* Device suspended */ int (*resume)(struct pci_dev *dev); /* Device woken up */

Removing an amdgpu device that still has user space references allocated to it causes undefined behaviour. So, implement amdgpu_pci_can_remove() and disallow devices that still have files allocated to them from being unbound.

Cc: stable@vger.kernel.org Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c index cc69005f5b46..cfa64f3c5be5 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -2323,6 +2323,22 @@ static int amdgpu_pci_probe(struct pci_dev *pdev, return ret; }

+static bool amdgpu_pci_can_remove(struct pci_dev *pdev) +{ + struct drm_device *dev = pci_get_drvdata(pdev); + + mutex_lock(&dev->filelist_mutex); + + if (!list_empty(&dev->filelist)) { + mutex_unlock(&dev->filelist_mutex); + return false; + } + + mutex_unlock(&dev->filelist_mutex); + + return true; +} + static void amdgpu_pci_remove(struct pci_dev *pdev) { @@ -2929,6 +2945,7 @@ static struct pci_driver amdgpu_kms_pci_driver = { .name = DRIVER_NAME, .id_table = pciidlist, .probe = amdgpu_pci_probe, + .can_remove = amdgpu_pci_can_remove, .remove = amdgpu_pci_remove, .shutdown = amdgpu_pci_shutdown, .driver.pm = &amdgpu_pm_ops,

Am 02.02.24 um 23:25 schrieb Hamza Mahfooz:

Currently, drivers have no mechanism to block requests to unbind devices. However, this can cause resource leaks and leave the device in an inconsistent state, such that rebinding the device may cause a hang or otherwise prevent the device from being rebound. So, introduce the can_remove() callback to allow drivers to indicate if it isn't appropriate to remove a device at the given time.

Well that is nonsense. When you physically remove a device (e.g. unplug it) then there is nothing in software you can do to prevent that.

Regards, Christian.

Cc: stable@vger.kernel.org Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com

---

drivers/base/bus.c | 4 ++++ include/linux/device/bus.h | 2 ++ 2 files changed, 6 insertions(+)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c index daee55c9b2d9..7c259b01ea99 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -239,6 +239,10 @@ static ssize_t unbind_store(struct device_driver *drv, const char *buf, dev = bus_find_device_by_name(bus, NULL, buf); if (dev && dev->driver == drv) {

• if (dev->bus && dev->bus->can_remove &&
  

•     !dev->bus->can_remove(dev))
  

• 	return -EBUSY;
  

• device_driver_detach(dev); err = count; }

diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index 5ef4ec1c36c3..c9d4af0ed3b8 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -46,6 +46,7 @@ struct fwnode_handle;

• be called at late_initcall_sync level. If the device has
  

• consumers that are never bound to a driver, this function
  

• will never get called until they do.
  

• • @can_remove: Called before attempting to remove a device from this bus.
  • @remove: Called when a device removed from this bus.
  • @shutdown: Called at shut-down time to quiesce the device.

@@ -85,6 +86,7 @@ struct bus_type { int (*uevent)(const struct device *dev, struct kobj_uevent_env *env); int (*probe)(struct device *dev); void (*sync_state)(struct device *dev);

• bool (*can_remove)(struct device *dev); void (*remove)(struct device *dev); void (*shutdown)(struct device *dev);