From: Bjorn Helgaas <helgaas@kernel.org>
To: Philipp Stanner <pstanner@redhat.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
Bjorn Helgaas <bhelgaas@google.com>,
Sam Ravnborg <sam@ravnborg.org>,
dakr@redhat.com, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH v6 00/10] Make PCI's devres API more consistent
Date: Wed, 24 Apr 2024 15:12:29 -0500 [thread overview]
Message-ID: <20240424201229.GA503230@bhelgaas> (raw)
In-Reply-To: <20240408084423.6697-1-pstanner@redhat.com>
On Mon, Apr 08, 2024 at 10:44:12AM +0200, Philipp Stanner wrote:
> ...
> 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.
There's a lot of good work here; thanks for working on it.
> Philipp Stanner (10):
> PCI: Add new set of devres functions
This first patch adds some infrastructure and several new exported
interfaces:
void __iomem *pcim_iomap_region(struct pci_dev *pdev, int bar, const char *name)
void pcim_iounmap_region(struct pci_dev *pdev, int bar)
int pcim_request_region(struct pci_dev *pdev, int bar, const char *name)
void pcim_release_region(struct pci_dev *pdev, int bar)
void __iomem *pcim_iomap_range(struct pci_dev *pdev, int bar,
void __iomem *pcim_iomap_region_range(struct pci_dev *pdev, int bar,
void pcim_iounmap_region_range(struct pci_dev *pdev, int bar,
> PCI: Deprecate iomap-table functions
This adds a little bit of infrastructure (add/remove to legacy_table),
reimplements these existing interfaces:
void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen)
void pcim_iounmap(struct pci_dev *pdev, void __iomem *addr)
int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
and adds a couple new exported interfaces:
void pcim_release_all_regions(struct pci_dev *pdev)
int pcim_request_all_regions(struct pci_dev *pdev, const char *name)
There's a lot going on in these two patches, so they're hard to
review. I think it would be easier if you could do the fixes to
existing interfaces first, followed by adding new things, maybe
something like separate patches that:
- Add pcim_addr_devres_alloc(), pcim_addr_devres_free(),
pcim_addr_devres_clear().
- Add pcim_add_mapping_to_legacy_table(),
pcim_remove_mapping_from_legacy_table(),
pcim_remove_bar_from_legacy_table().
- Reimplement pcim_iomap(), pcim_iomap_regions(), pcim_iounmap().
- Add new interfaces like pcim_iomap_region(),
pcim_request_region(), etc.
AFAICS, except for pcim_iomap_range() (used by vbox), these new
interfaces have no users outside drivers/pci, so ... we might
defer adding them, or at least defer exposing them via
include/linux/pci.h, until we have users for them.
> PCI: Warn users about complicated devres nature
> PCI: Make devres region requests consistent
> 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()
> drm/vboxvideo: fix mapping leaks
>
> drivers/gpu/drm/vboxvideo/vbox_main.c | 20 +-
> drivers/pci/devres.c | 1011 +++++++++++++++++++++----
> drivers/pci/iomap.c | 18 +
> drivers/pci/pci.c | 123 ++-
> drivers/pci/pci.h | 21 +-
> include/linux/pci.h | 18 +-
> 6 files changed, 999 insertions(+), 212 deletions(-)
>
> --
> 2.44.0
>
next prev parent reply other threads:[~2024-04-24 20:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-08 8:44 [PATCH v6 00/10] Make PCI's devres API more consistent Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 01/10] PCI: Add new set of devres functions Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 02/10] PCI: Deprecate iomap-table functions Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 03/10] PCI: Warn users about complicated devres nature Philipp Stanner
2024-04-24 20:12 ` Bjorn Helgaas
2024-04-08 8:44 ` [PATCH v6 04/10] PCI: Make devres region requests consistent Philipp Stanner
2024-04-24 20:12 ` Bjorn Helgaas
2024-04-26 7:45 ` Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 05/10] PCI: Move dev-enabled status bit to struct pci_dev Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 06/10] PCI: Move pinned " Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 07/10] PCI: Give pcim_set_mwi() its own devres callback Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 08/10] PCI: Give pci(m)_intx " Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 09/10] PCI: Remove legacy pcim_release() Philipp Stanner
2024-04-08 8:44 ` [PATCH v6 10/10] drm/vboxvideo: fix mapping leaks Philipp Stanner
2024-04-22 7:23 ` [PATCH v6 00/10] Make PCI's devres API more consistent Philipp Stanner
2024-04-24 20:12 ` Bjorn Helgaas [this message]
2024-04-26 8:07 ` Philipp Stanner
2024-04-26 22:01 ` Bjorn Helgaas
2024-05-07 8:11 ` Philipp Stanner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240424201229.GA503230@bhelgaas \
--to=helgaas@kernel.org \
--cc=airlied@gmail.com \
--cc=bhelgaas@google.com \
--cc=dakr@redhat.com \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=hdegoede@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=maarten.lankhorst@linux.intel.com \
--cc=mripard@kernel.org \
--cc=pstanner@redhat.com \
--cc=sam@ravnborg.org \
--cc=tzimmermann@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).