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2020-12-05drm: Remove drmm_add_final_kfree() declaration from public headersLaurent Pinchart1-2/+0
The drmm_add_final_kfree() function is declared in the include/drm/drm_managed.h public header, but has become an internal API not exposed to drivers. Drop it from drm_managed.h as it's already declared in drm_internal.h. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20201204092932.21636-1-laurent.pinchart+renesas@ideasonboard.com
2020-03-26drm: Add docs for managed resourcesDaniel Vetter1-0/+55
All collected together to provide a consistent story in one patch, instead of the somewhat bumpy refactor-evolution leading to this. Also some thoughts on what the next steps could be: - Create a macro called devm_drm_dev_alloc() which essentially wraps the kzalloc(); devm_drm_dev_init(); drmm_add_final_kfree() combo. Needs to be a macro since we'll have to do some typeof trickery and casting to make this fully generic for all drivers that embed struct drm_device into their own thing. - A lot of the simple drivers now have essentially just drm_dev_unplug(); drm_atomic_helper_shutdown(); as their $bus_driver->remove hook. We could create a devm_mode_config_reset which sets drm_atomic_helper_shutdown as it's cleanup action, and a devm_drm_dev_register with drm_dev_unplug as it's cleanup action, and simple drivers wouldn't have a need for a ->remove function at all, and we could delete them. - For more complicated drivers we need drmm_ versions of a _lot_ more things. All the userspace visible objects (crtc, plane, encoder, crtc), anything else hanging of those (maybe a drmm_get_edid, at least for panels and other built-in stuff). Also some more thoughts on why we're not reusing devm_ with maybe a fake struct device embedded into the drm_device (we can't use the kdev, since that's in each drm_minor). - Code review gets extremely tricky, since every time you see a devm_ you need to carefully check whether the fake device (with the drm_device lifetim) or the real device (with the lifetim of the underlying physical device and driver binding) are used. That's not going to help at all, and we have enormous amounts of drivers who use devm_ where they really shouldn't. Having different types makes sure the compiler type checks this for us and ensures correctness. - The set of functions are very much non-overlapping. E.g. devm_ioremap makes total sense, drmm_ioremap has the wrong lifetime, since hw resources need to be cleaned out at driver unbind and wont outlive that like a drm_device. Similar, but other way round for drmm_connector_init (which is the only correct version, devm_ for drm_connector is just buggy). Simply not having the wrong version again prevents bugs. Finally I guess this opens a huge todo for all the drivers. I'm semi-tempted to do a tree-wide s/devm_kzalloc/drmm_kzalloc/ since most likely that'll fix an enormous amount of bugs and most likely not cause any issues at all (aside from maybe holding onto memory slightly too long). v2: - Doc improvements from Laurent. - Also add kerneldoc for the new drmm_add_action_or_reset. v3: - Remove kerneldoc for drmm_remove_action. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> fixup docs Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-52-daniel.vetter@ffwll.ch
2020-03-26drm: Manage drm_vblank_cleanup with drmm_Daniel Vetter1-0/+16
Nothing special here, except that this is the first time that we automatically clean up something that's initialized with an explicit driver call. But the cleanup was done at the very end of the release sequence for all drivers, and that's still the case. At least without more uses of drmm_ through explicit driver calls. Also for this one we need drmm_kcalloc, so lets add those. The motivation here is to allow us to remove the explicit calls to drm_dev_fini() from all drivers. v2: Sort includes (Laurent) v3: Motivate the change in the commit message better (Sam) Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-25-daniel.vetter@ffwll.ch
2020-03-26drm: manage drm_minor cleanup with drmm_Daniel Vetter1-1/+8
The cleanup here is somewhat tricky, since we can't tell apart the allocated minor index from 0. So register a cleanup action first, and if the index allocation fails, unregister that cleanup action again to avoid bad mistakes. The kdev for the minor already handles NULL, so no problem there. Hence add drmm_remove_action() to the drm_managed library. v2: Make pointer math around void ** consistent with what Laurent suggested. v3: Use drmm_add_action_or_reset and remove drmm_remove_action. Noticed because of some questions from Thomas. This also means we need to move the drmm_add_action_or_reset helper earlier in the series. v4: Uh ... fix slightly embarrassing bug CI spotted. Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200324203936.3330994-1-daniel.vetter@ffwll.ch
2020-03-26drm: Handle dev->unique with drmm_Daniel Vetter1-0/+1
We need to add a drmm_kstrdup for this, but let's start somewhere. This is not exactly perfect onion unwinding, but it's jsut a kfree so doesn't really matter at all. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-21-daniel.vetter@ffwll.ch
2020-03-26drm: add managed resources tied to drm_deviceDaniel Vetter1-0/+30
We have lots of these. And the cleanup code tends to be of dubious quality. The biggest wrong pattern is that developers use devm_, which ties the release action to the underlying struct device, whereas all the userspace visible stuff attached to a drm_device can long outlive that one (e.g. after a hotunplug while userspace has open files and mmap'ed buffers). Give people what they want, but with more correctness. Mostly copied from devres.c, with types adjusted to fit drm_device and a few simplifications - I didn't (yet) copy over everything. Since the types don't match code sharing looked like a hopeless endeavour. For now it's only super simplified, no groups, you can't remove actions (but kfree exists, we'll need that soon). Plus all specific to drm_device ofc, including the logging. Which I didn't bother to make compile-time optional, since none of the other drm logging is compile time optional either. One tricky bit here is the chicken&egg between allocating your drm_device structure and initiliazing it with drm_dev_init. For perfect onion unwinding we'd need to have the action to kfree the allocation registered before drm_dev_init registers any of its own release handlers. But drm_dev_init doesn't know where exactly the drm_device is emebedded into the overall structure, and by the time it returns it'll all be too late. And forcing drivers to be able clean up everything except the one kzalloc is silly. Work around this by having a very special final_kfree pointer. This also avoids troubles with the list head possibly disappearing from underneath us when we release all resources attached to the drm_device. v2: Do all the kerneldoc at the end, to avoid lots of fairly pointless shuffling while getting everything into shape. v3: Add static to add/del_dr (Neil) Move typo fix to the right patch (Neil) v4: Enforce contract for drmm_add_final_kfree: Use ksize() to check that the drm_device is indeed contained somewhere in the final kfree(). Because we need that or the entire managed release logic blows up in a pile of use-after-frees. Motivated by a discussion with Laurent. v5: Review from Laurent: - %zu instead of casting size_t - header guards - sorting of includes - guarding of data assignment if we didn't allocate it for a NULL pointer - delete spurious newline - cast void* data parameter correctly in ->release call, no idea how this even worked before v6: Review from Sam - Add the kerneldoc for the managed sub-struct back in, even if it doesn't show up in the generated html somehow. - Explain why __always_inline. - Fix bisectability around the final kfree() in drm_dev_relase(). This is just interim code which will disappear again. - Some whitespace polish. - Add debug output when drmm_add_action or drmm_kmalloc fail. v7: My bisectability fix wasn't up to par as noticed by smatch. v8: Remove unecessary {} around if else v9: Use kstrdup_const, which requires kfree_const and introducing a free_dr() helper (Thomas). v10: kfree_const goes boom on the plain "kmalloc" assignment, somehow we need to wrap that in kstrdup_const() too!! Also renumber revision log, I somehow reset it midway thruh. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Neil Armstrong <narmstrong@baylibre.com Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200324124540.3227396-1-daniel.vetter@ffwll.ch