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2925c2fdf1
Currently the first thing we do in cxl_probe is to grab a reference
on the pci device. Later on, we call device_register on our adapter.
In our remove path, we call device_unregister, but we never call
pci_dev_put. We therefore leak the device every time we do a
reflash.
device_register/unregister is sufficient to hold the reference.
Therefore, drop the call to pci_dev_get.
Here's why this is safe.
The proposed cxl_probe(pdev) calls cxl_adapter_init:
a) init calls cxl_adapter_alloc, which creates a struct cxl,
conventionally called adapter. This struct contains a
device entry, adapter->dev.
b) init calls cxl_configure_adapter, where we set
adapter->dev.parent = &dev->dev (here dev is the pci dev)
So at this point, the cxl adapter's device's parent is the PCI
device that I want to be refcounted properly.
c) init calls cxl_register_adapter
*) cxl_register_adapter calls device_register(&adapter->dev)
So now we're in device_register, where dev is the adapter device, and
we want to know if the PCI device is safe after we return.
device_register(&adapter->dev) calls device_initialize() and then
device_add().
device_add() does a get_device(). device_add() also explicitly grabs
the device's parent, and calls get_device() on it:
parent = get_device(dev->parent);
So therefore, device_register() takes a lock on the parent PCI dev,
which is what pci_dev_get() was guarding. pci_dev_get() can therefore
be safely removed.
Fixes:
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.. | ||
api.c | ||
base.c | ||
context.c | ||
cxl.h | ||
debugfs.c | ||
fault.c | ||
file.c | ||
irq.c | ||
Kconfig | ||
main.c | ||
Makefile | ||
native.c | ||
pci.c | ||
sysfs.c | ||
trace.c | ||
trace.h | ||
vphb.c |