From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
DRI Development <dri-devel@lists.freedesktop.org>,
Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Daniel Vetter <daniel.vetter@intel.com>,
Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [PATCH 01/59] drm: Add devm_drm_dev_alloc macro
Date: Tue, 21 Apr 2020 12:45:49 +0200 [thread overview]
Message-ID: <CAKMK7uH2vhrQ7eTTF1B+==UJS9ZxhDv2RDvR0ct4P0vVJobf=w@mail.gmail.com> (raw)
In-Reply-To: <4d5229c2-acb4-b76f-13c7-88a5f3de4760@suse.de>
On Mon, Apr 20, 2020 at 3:37 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
>
> Hi
>
> Am 15.04.20 um 09:39 schrieb Daniel Vetter:
> > Add a new macro helper to combine the usual init sequence in drivers,
> > consisting of a kzalloc + devm_drm_dev_init + drmm_add_final_kfree
> > triplet. This allows us to remove the rather unsightly
> > drmm_add_final_kfree from all currently merged drivers.
> >
> > The kerneldoc is only added for this new function. Existing kerneldoc
> > and examples will be udated at the very end, since once all drivers
> > are converted over to devm_drm_dev_alloc we can unexport a lot of
> > interim functions and make the documentation for driver authors a lot
> > cleaner and less confusing. There will be only one true way to
> > initialize a drm_device at the end of this, which is going to be
> > devm_drm_dev_alloc.
> >
> > v2:
> > - Actually explain what this is for in the commit message (Sam)
> > - Fix checkpatch issues (Sam)
> >
> > Acked-by: Noralf Trønnes <noralf@tronnes.org>
> > Cc: Noralf Trønnes <noralf@tronnes.org>
> > Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Thanks for taking a look, some questions on your suggestions below.
> Sorry for being late. A number of nits are listed below. In any case:
>
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
>
> Best regards
> Thomas
>
> > ---
> > drivers/gpu/drm/drm_drv.c | 23 +++++++++++++++++++++++
> > include/drm/drm_drv.h | 33 +++++++++++++++++++++++++++++++++
> > 2 files changed, 56 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > index 1bb4f636b83c..8e1813d2a12e 100644
> > --- a/drivers/gpu/drm/drm_drv.c
> > +++ b/drivers/gpu/drm/drm_drv.c
> > @@ -739,6 +739,29 @@ int devm_drm_dev_init(struct device *parent,
> > }
> > EXPORT_SYMBOL(devm_drm_dev_init);
> >
> > +void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,
> > + size_t size, size_t offset)
>
> Maybe rename 'offset' of 'dev_offset' to make the relationship clear.
Hm, I see the point of this (and the dev_field below, although I'd go
with dev_member there for some consistency with other macros using
offset_of or container_of), but I'm not sure about the dev_ prefix.
Drivers use that sometimes for the struct device *, and usage for
struct drm_device * is also very inconsistent. I've seen ddev, drm,
dev and base (that one only for embedded structs ofc). So not sure
which prefix to pick, aside from dev_ seems the most confusing. Got
ideas?
> > +{
> > + void *container;
> > + struct drm_device *drm;
> > + int ret;
> > +
> > + container = kzalloc(size, GFP_KERNEL);
> > + if (!container)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + drm = container + offset;
>
> While convenient, I somewhat dislike the use of void* variables. I'd use
> unsigned char* for container and do an explicit cast to struct
> drm_device* here.
I thought ever since C89 the explicit recommendation for untyped
pointer math has been void *, and no longer char *, with the spec
being explicit that void * pointer math works exactly like char *. So
not clear on why you think char * is preferred here. I'm also not
aware of any other kernel code that casts to char * for untyped
pointer math. So unless you have some supporting evidence, I'll skip
this one, ok?
Thanks, Daniel
> > + ret = devm_drm_dev_init(parent, drm, driver);
> > + if (ret) {
> > + kfree(container);
> > + return ERR_PTR(ret);
> > + }
> > + drmm_add_final_kfree(drm, container);
> > +
> > + return container;
> > +}
> > +EXPORT_SYMBOL(__devm_drm_dev_alloc);
> > +
> > /**
> > * drm_dev_alloc - Allocate new DRM device
> > * @driver: DRM driver to allocate device for
> > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> > index e7c6ea261ed1..f07f15721254 100644
> > --- a/include/drm/drm_drv.h
> > +++ b/include/drm/drm_drv.h
> > @@ -626,6 +626,39 @@ int devm_drm_dev_init(struct device *parent,
> > struct drm_device *dev,
> > struct drm_driver *driver);
> >
> > +void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver,
> > + size_t size, size_t offset);
> > +
> > +/**
> > + * devm_drm_dev_alloc - Resource managed allocation of a &drm_device instance
> > + * @parent: Parent device object
> > + * @driver: DRM driver
> > + * @type: the type of the struct which contains struct &drm_device
> > + * @member: the name of the &drm_device within @type.
> > + *
> > + * This allocates and initialize a new DRM device. No device registration is done.
> > + * Call drm_dev_register() to advertice the device to user space and register it
> > + * with other core subsystems. This should be done last in the device
> > + * initialization sequence to make sure userspace can't access an inconsistent
> > + * state.
> > + *
> > + * The initial ref-count of the object is 1. Use drm_dev_get() and
> > + * drm_dev_put() to take and drop further ref-counts.
> > + *
> > + * It is recommended that drivers embed &struct drm_device into their own device
> > + * structure.
> > + *
> > + * Note that this manages the lifetime of the resulting &drm_device
> > + * automatically using devres. The DRM device initialized with this function is
> > + * automatically put on driver detach using drm_dev_put().
> > + *
> > + * RETURNS:
> > + * Pointer to new DRM device, or ERR_PTR on failure.
> > + */
> > +#define devm_drm_dev_alloc(parent, driver, type, member) \
>
> I'd replace 'member' with 'dev_field' to make the relation ship clear.
>
> > + ((type *) __devm_drm_dev_alloc(parent, driver, sizeof(type), \
> > + offsetof(type, member)))
> > +
> > struct drm_device *drm_dev_alloc(struct drm_driver *driver,
> > struct device *parent);
> > int drm_dev_register(struct drm_device *dev, unsigned long flags);
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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next prev parent reply other threads:[~2020-04-21 10:46 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 7:39 [PATCH 00/59] devm_drm_dev_alloc, v2 Daniel Vetter
2020-04-15 7:39 ` [PATCH 01/59] drm: Add devm_drm_dev_alloc macro Daniel Vetter
2020-04-20 13:36 ` Thomas Zimmermann
2020-04-21 10:45 ` Daniel Vetter [this message]
2020-04-21 14:03 ` Thomas Zimmermann
2020-04-21 20:32 ` Sam Ravnborg
2020-04-28 13:06 ` Daniel Vetter
2020-04-15 7:39 ` [PATCH 02/59] drm/vboxvideo: drop DRM_MTRR_WC #define Daniel Vetter
2020-04-15 15:01 ` Hans de Goede
2020-04-15 7:39 ` [PATCH 03/59] drm/vboxvideo: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 15:02 ` Hans de Goede
2020-04-24 16:33 ` Sam Ravnborg
2020-04-15 7:39 ` [PATCH 04/59] drm/vboxvideo: Stop using drm_device->dev_private Daniel Vetter
2020-04-15 15:02 ` Hans de Goede
2020-04-15 7:39 ` [PATCH 05/59] drm/vboxvidoe: use managed pci functions Daniel Vetter
2020-04-15 15:03 ` Hans de Goede
2020-04-15 17:44 ` Daniel Vetter
2020-04-20 13:16 ` Hans de Goede
2020-04-15 17:32 ` Thomas Zimmermann
2020-04-15 7:39 ` [PATCH 06/59] drm/vboxvideo: Use devm_gen_pool_create Daniel Vetter
2020-04-15 15:04 ` Hans de Goede
2020-04-15 7:39 ` [PATCH 07/59] drm/v3d: Don't set drm_device->dev_private Daniel Vetter
2020-04-15 7:39 ` [PATCH 08/59] drm/v3d: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:39 ` [PATCH 09/59] drm/v3d: Delete v3d_dev->dev Daniel Vetter
2020-04-15 7:39 ` [PATCH 10/59] drm/v3d: Delete v3d_dev->pdev Daniel Vetter
2020-04-15 7:39 ` [PATCH 11/59] drm/udl: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:55 ` Thomas Zimmermann
2020-04-24 14:55 ` Sam Ravnborg
2020-04-28 13:18 ` Daniel Vetter
2020-04-15 7:39 ` [PATCH 12/59] drm/udl: don't set drm_device->dev_private Daniel Vetter
2020-04-15 7:39 ` [PATCH 13/59] drm/st7735r: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:39 ` [PATCH 14/59] drm/st7586: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 15/59] drm/repaper: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 16/59] drm/mi0283qt: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 17/59] drm/ili9486: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 18/59] drm/ili9341: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 19/59] drm/ili9225: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 20/59] drm/hx8357d: " Daniel Vetter
2020-04-15 7:39 ` [PATCH 21/59] drm/gm12u320: " Daniel Vetter
2020-04-15 15:04 ` Hans de Goede
2020-04-15 7:39 ` [PATCH 22/59] drm/gm12u320: Don't use drm_device->dev_private Daniel Vetter
2020-04-15 15:05 ` Hans de Goede
2020-04-15 7:39 ` [PATCH 23/59] drm/tidss: Use devm_drm_dev_alloc Daniel Vetter
2020-04-21 11:03 ` Tomi Valkeinen
2020-04-15 7:39 ` [PATCH 24/59] drm/tidss: Don't use drm_device->dev_private Daniel Vetter
2020-04-21 11:05 ` Tomi Valkeinen
2020-04-15 7:40 ` [PATCH 25/59] drm/tidss: Delete tidss->saved_state Daniel Vetter
2020-04-21 11:05 ` Tomi Valkeinen
2020-04-15 7:40 ` [PATCH 26/59] drm/qxl: Use devm_drm_dev_alloc Daniel Vetter
2020-04-24 15:09 ` Sam Ravnborg
2020-04-28 14:00 ` Daniel Vetter
2020-04-28 17:00 ` Sam Ravnborg
2020-04-28 18:04 ` Daniel Vetter
2020-04-15 7:40 ` [PATCH 27/59] drm/qxl: Don't use drm_device->dev_private Daniel Vetter
2020-04-24 15:12 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 28/59] drm/mcde: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 12:20 ` Linus Walleij
2020-04-15 7:40 ` [PATCH 29/59] drm/mcde: Don't use drm_device->dev_private Daniel Vetter
2020-04-15 7:40 ` [PATCH 30/59] drm/ingenic: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:40 ` [PATCH 31/59] drm/ingenic: Don't set drm_device->dev_private Daniel Vetter
2020-04-15 7:40 ` [PATCH 32/59] drm/komeda: use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:40 ` [PATCH 33/59] drm/armada: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:40 ` [PATCH 34/59] drm/armada: Don't use drm_device->dev_private Daniel Vetter
2020-04-15 7:40 ` [PATCH 35/59] drm/cirrus: Use devm_drm_dev_alloc Daniel Vetter
2020-04-15 7:40 ` [PATCH 36/59] drm/cirrus: Don't use drm_device->dev_private Daniel Vetter
2020-04-15 7:40 ` [PATCH 37/59] drm/cirrus: Move to drm/tiny Daniel Vetter
2020-04-15 8:01 ` Thomas Zimmermann
2020-04-15 8:19 ` Daniel Vetter
2020-04-15 8:46 ` Thomas Zimmermann
2020-04-15 9:31 ` Daniel Vetter
2020-04-21 7:37 ` Gerd Hoffmann
2020-04-24 16:37 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 38/59] drm/i915: Use devm_drm_dev_alloc Daniel Vetter
2020-04-28 18:52 ` Daniel Vetter
2020-04-15 7:40 ` [PATCH 39/59] drm/arcpgu: Switch to devm_drm_dev_alloc Daniel Vetter
2020-04-24 16:43 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 40/59] drm/arcpgu: Stop using drm_device->dev_private Daniel Vetter
2020-04-24 16:46 ` Sam Ravnborg
2020-09-04 13:42 ` Daniel Vetter
2020-09-04 14:42 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 41/59] drm/arcpgu: Delete arcpgu_priv->fb Daniel Vetter
2020-04-24 16:47 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 42/59] drm/arc: Embedded a drm_simple_display_pipe Daniel Vetter
2020-04-24 17:34 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 43/59] drm/arc: Embedd a drm_connector for sim case Daniel Vetter
2020-04-24 17:34 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 44/59] drm/arc: Drop surplus connector registration Daniel Vetter
2020-04-24 16:51 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 45/59] drm/arc: Use drmm_mode_config_cleanup Daniel Vetter
2020-04-24 17:36 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 46/59] drm/arc: Align with simple pipe helpers Daniel Vetter
2020-04-25 12:24 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 47/59] drm/arc: Convert to drm_simple_kms_pipe_helper Daniel Vetter
2020-04-24 17:40 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 48/59] drm/arc: Drop fb/crtc check in arc_pgu_update Daniel Vetter
2020-04-24 17:45 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 49/59] drm/arc: Inline arcpgu_crtc.c Daniel Vetter
2020-04-24 17:51 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 50/59] drm/arc: Inline arcpgu_drm_hdmi_init Daniel Vetter
2020-04-24 17:54 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 51/59] drm/arc: Inline remaining files Daniel Vetter
2020-04-24 17:56 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 52/59] drm/arc: Initialize sim connector before display pipe Daniel Vetter
2020-04-24 17:58 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 53/59] drm/arc: Move to drm/tiny Daniel Vetter
2020-04-15 8:04 ` Thomas Zimmermann
2020-04-15 8:22 ` Daniel Vetter
2020-04-15 9:45 ` Sam Ravnborg
2020-04-15 12:02 ` Alexey Brodkin
2020-04-15 12:20 ` Daniel Vetter
2020-04-28 14:08 ` Daniel Vetter
2020-05-08 13:56 ` Alexey Brodkin
2020-05-08 18:07 ` Daniel Vetter
2020-06-04 8:05 ` Daniel Vetter
2020-06-04 10:38 ` Eugeniy Paltsev
2020-06-04 11:19 ` Daniel Vetter
2020-06-04 19:00 ` Eugeniy Paltsev
2020-06-05 19:55 ` Daniel Vetter
2020-06-09 12:08 ` Eugeniy Paltsev
2020-06-09 13:02 ` Daniel Vetter
2020-07-17 9:04 ` Daniel Vetter
2020-04-15 7:40 ` [PATCH 54/59] drm/aspeed: Drop aspeed_gfx->fbdev Daniel Vetter
2020-04-24 18:00 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 55/59] drm/aspeed: Use devm_drm_dev_alloc Daniel Vetter
2020-04-24 18:02 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 56/59] drm/aspeed: Use managed drmm_mode_config_cleanup Daniel Vetter
2020-04-24 18:10 ` Sam Ravnborg
2020-04-28 14:12 ` Daniel Vetter
2020-04-28 17:03 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 57/59] drm/ast: Use managed pci functions Daniel Vetter
2020-04-15 7:52 ` Thomas Zimmermann
2020-04-15 8:09 ` Daniel Vetter
2020-04-15 8:17 ` Daniel Vetter
2020-04-15 12:23 ` Daniel Vetter
2020-06-11 12:04 ` Thomas Zimmermann
2020-06-16 11:55 ` Daniel Vetter
2020-04-15 7:40 ` [PATCH 58/59] drm/ast: Drop explicit connector register/unregister Daniel Vetter
2020-04-15 7:53 ` Thomas Zimmermann
2020-04-24 18:11 ` Sam Ravnborg
2020-04-15 7:40 ` [PATCH 59/59] drm/bochs: Remove explicit drm_connector_register Daniel Vetter
2020-04-21 7:39 ` Gerd Hoffmann
2020-04-24 18:11 ` Sam Ravnborg
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