From: Ira Weiny <ira.weiny@xxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Link: https://lore.kernel.org/r/20231220-cxl-cper-v5-8-1bb8a4ca2c7a@xxxxxxxxx
[djbw: rewrite changelog]
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
[lukas: drop DEFINE_GUARD() helper as pci_dev_lock() doesn't exist in v5.15]
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
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);
--
2.43.0
