On Wed, Jun 05, 2024 at 10:15:52AM +0200, Philipp Stanner wrote: > Hello Bjorn, > > I tried to meet your requests from the last feedback round as much as > possible. Especially, I removed a lot of code, made almost all > interfaces private and cut the series into smaller chunks where > possible. > > Splitting it even smaller is unfortunately not possible because of the > Linux kernel build chain's rule on dead / unused code. > > See also the changelog below. > > Please tell me if that's enough to move forward here. > > Regards, > P. > > > Changes in v7: > - Split the entire series in smaller, more atomic chunks / patches > (Bjorn) > - Remove functions (such as pcim_iomap_region_range()) that do not yet > have a user (Bjorn) > - Don't export interfaces publicly anymore, except for > pcim_iomap_range(), needed by vboxvideo (Bjorn) > - Mention the actual (vboxvideo) bug in "PCI: Warn users..." commit > (Bjorn) > - Drop docstring warnings on PCI-internal functions (Bjorn) > - Rework docstring warnings > - Fix spelling in a few places. Rewrapp paragraphs (Bjorn) > > Changes in v6: > - Restructure the cleanup in pcim_iomap_regions_request_all() so that > it doesn't trigger a (false positive) test robot warning. No > behavior change intended. (Dan Carpenter) > > Changes in v5: > - Add Hans's Reviewed-by to vboxvideo patch (Hans de Goede) > - Remove stable-kernel from CC in vboxvideo patch (Hans de Goede) > > Changes in v4: > - Rebase against linux-next > > Changes in v3: > - Use the term "PCI devres API" at some forgotten places. > - Fix more grammar errors in patch #3. > - Remove the comment advising to call (the outdated) pcim_intx() in pci.c > - Rename __pcim_request_region_range() flags-field "exclusive" to > "req_flags", since this is what the int actually represents. > - Remove the call to pcim_region_request() from patch #10. (Hans) > > Changes in v2: > - Make commit head lines congruent with PCI's style (Bjorn) > - Add missing error checks for devm_add_action(). (Andy) > - Repair the "Returns: " marks for docu generation (Andy) > - Initialize the addr_devres struct with memset(). (Andy) > - Make pcim_intx() a PCI-internal function so that new drivers won't > be encouraged to use the outdated pci_intx() mechanism. > (Andy / Philipp) > - Fix grammar and spelling (Bjorn) > - Be more precise on why pcim_iomap_table() is problematic (Bjorn) > - Provide the actual structs' and functions' names in the commit > messages (Bjorn) > - Remove redundant variable initializers (Andy) > - Regroup PM bitfield members in struct pci_dev (Andy) > - Make pcim_intx() visible only for the PCI subsystem so that new > drivers won't use this outdated API (Andy, Myself) > - Add a NOTE to pcim_iomap() to warn about this function being the onee > xception that does just return NULL. > - Consistently use the term "PCI devres API"; also in Patch #10 (Bjorn) > > > ¡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. > > Philipp Stanner (13): > PCI: Add and use devres helper for bit masks > PCI: Add devres helpers for iomap table > PCI: Reimplement plural devres functions > PCI: Deprecate two surplus devres functions > PCI: Make devres region requests consistent > PCI: Warn users about complicated devres nature Applied the above to pci/devres for v6.11 with minor comment and whitespace tweaks. Will watch for updates for the ones below to consolidate "enabled" and "enable_cnt". > PCI: Move dev-enabled status bit to struct pci_dev > PCI: Move pinned status bit to struct pci_dev > PCI: Give pcim_set_mwi() its own devres callback > PCI: Give pci(m)_intx its own devres callback > PCI: Remove legacy pcim_release() > PCI: Add pcim_iomap_range() > drm/vboxvideo: fix mapping leaks > > drivers/gpu/drm/vboxvideo/vbox_main.c | 20 +- > drivers/pci/devres.c | 897 +++++++++++++++++++++----- > drivers/pci/iomap.c | 16 + > drivers/pci/pci.c | 107 ++- > drivers/pci/pci.h | 23 +- > include/linux/pci.h | 6 +- > 6 files changed, 864 insertions(+), 205 deletions(-) > > -- > 2.45.0 >
