¡Hola! PCI's devres API suffers several weaknesses: 1. There are functions prefixed with pcim_. Those are always managed counterparts to never-managed functions prefixed with pci_ – or so one would like to think. There are some apparently unmanaged functions (all region-request / release functions, and pci_intx()) which suddenly become managed once the user has initialized the device with pcim_enable_device() instead of pci_enable_device(). This "sometimes yes, sometimes no" nature of those functions is confusing and therefore bug-provoking. In fact, it has already caused a bug in DRM. The last patch in this series fixes that bug. 2. iomappings: Instead of giving each mapping its own callback, the existing API uses a statically allocated struct tracking one mapping per bar. This is not extensible. Especially, you can't create _ranged_ managed mappings that way, which many drivers want. 3. Managed request functions only exist as "plural versions" with a bit-mask as a parameter. That's quite over-engineered considering that each user only ever mapps one, maybe two bars. This series: - add a set of new "singular" devres functions that use devres the way its intended, with one callback per resource. - deprecates the existing iomap-table mechanism. - deprecates the hybrid nature of pci_ functions. - preserves backwards compatibility so that drivers using the existing API won't notice any changes. - adds documentation, especially some warning users about the complicated nature of PCI's devres. Note that this series is based on my "unify pci_iounmap"-series from a few weeks ago. [1] I tested this on a x86 VM with a simple pci test-device with two regions. Operates and reserves resources as intended on my system. Kasan and kmemleak didn't find any problems. I believe this series cleans the API up as much as possible without having to port all existing drivers to the new API. Especially, I think that this implementation is easy to extend if the need for new managed functions arises :) Greetings, P. [1] https://lore.kernel.org/lkml/20240111085540.7740-1-pstanner@xxxxxxxxxx/ Philipp Stanner (10): pci: add new set of devres functions pci: deprecate iomap-table functions pci: warn users about complicated devres nature pci: devres: make devres region requests consistent pci: move enabled status bit to pci_dev struct pci: move pinned status bit to pci_dev struct pci: devres: give mwi its own callback pci: devres: give pci(m)_intx its own callback pci: devres: remove legacy pcim_release() drm/vboxvideo: fix mapping leaks Documentation/driver-api/pci/pci.rst | 3 + drivers/gpu/drm/vboxvideo/vbox_main.c | 24 +- drivers/pci/devres.c | 996 ++++++++++++++++++++++---- drivers/pci/iomap.c | 18 + drivers/pci/pci.c | 124 +++- drivers/pci/pci.h | 24 - include/linux/pci.h | 17 + 7 files changed, 989 insertions(+), 217 deletions(-) -- 2.43.0
