From: Ira Weiny ira.weiny@intel.com
commit ced085ef369af7a2b6da962ec2fbd01339f60693 upstream.
The "goto error" pattern is notorious for introducing subtle resource leaks. Use the new cleanup.h helpers for PCI device reference counts.
Similar to the new put_device() cleanup helper, __free(put_device), define the same for PCI devices, __free(pci_dev_put). These helpers eliminate the need for "goto free;" patterns. For example, a 'struct pci_dev *' instance declared as:
struct pci_dev *pdev __free(pci_dev_put) = NULL;
...will automatically call pci_dev_put() if @pdev is non-NULL when @pdev goes out of scope (automatic variable scope). If a function wants to invoke pci_dev_put() on error, but return @pdev on success, it can do:
return no_free_ptr(pdev);
...or:
return_ptr(pdev);
For potential cleanup opportunity there are 587 open-coded calls to pci_dev_put() in the kernel with 65 instances within 10 lines of a goto statement with the CXL driver threatening to add another one.
Cc: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Ira Weiny ira.weiny@intel.com Link: https://lore.kernel.org/r/20231220-cxl-cper-v5-8-1bb8a4ca2c7a@intel.com [djbw: rewrite changelog] Acked-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Jonathan Cameron Jonathan.Cameron@huawei.com Acked-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Dan Williams dan.j.williams@intel.com [lukas: drop DEFINE_GUARD() helper as pci_dev_lock() doesn't exist in v5.15] Signed-off-by: Lukas Wunner lukas@wunner.de --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+)
diff --git a/include/linux/pci.h b/include/linux/pci.h index 32805c3a37bb..20199983a283 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1122,6 +1122,7 @@ int pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge); u8 pci_common_swizzle(struct pci_dev *dev, u8 *pinp); struct pci_dev *pci_dev_get(struct pci_dev *dev); void pci_dev_put(struct pci_dev *dev); +DEFINE_FREE(pci_dev_put, struct pci_dev *, if (_T) pci_dev_put(_T)) void pci_remove_bus(struct pci_bus *b); void pci_stop_and_remove_bus_device(struct pci_dev *dev); void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev);