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Date:   Wed, 9 Jan 2019 22:20:09 +0100
From:   Daniel Vetter <daniel@ffwll.ch>
To:     Sam Ravnborg <sam@ravnborg.org>
Cc:     Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Sean Paul <sean@poorly.run>,
        David Lechner <david@lechnology.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Noralf =?iso-8859-1?Q?Tr=F8nnes?= <noralf@tronnes.org>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Alex Deucher <alexander.deucher@amd.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        "David (ChunMing) Zhou" <David1.Zhou@amd.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Rob Clark <robdclark@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Eric Anholt <eric@anholt.net>
Subject: Re: [PATCH v3 04/12] drm: move drm_can_sleep() to drm_util.h
Message-ID: <20190109212008.GY21184@phenom.ffwll.local>
Mail-Followup-To: Sam Ravnborg <sam@ravnborg.org>,
        David Airlie <airlied@linux.ie>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Sean Paul <sean@poorly.run>, David Lechner <david@lechnology.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Noralf =?iso-8859-1?Q?Tr=F8nnes?= <noralf@tronnes.org>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Alex Deucher <alexander.deucher@amd.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        "David (ChunMing) Zhou" <David1.Zhou@amd.com>,
        Gerd Hoffmann <kraxel@redhat.com>, Rob Clark <robdclark@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Eric Anholt <eric@anholt.net>
References: <20190108192939.15255-1-sam@ravnborg.org>
 <20190108192939.15255-5-sam@ravnborg.org>
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On Tue, Jan 08, 2019 at 08:29:31PM +0100, Sam Ravnborg wrote:
> Move drm_can_sleep() out of drmP.h to allow users
> to get rid of the drmP.h include.
> 
> There was no header file that was a good match for this helper function.
> So add this to drm_util with the relevant includes.
> 
> Update comments to use kernel-doc style.
> Add FIXME to drm_can_sleep and add note
> that this function should not be used in new code
> 
> Add include of drm_util.h to all users.
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "Christian K?nig" <christian.koenig@amd.com>
> Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: Eric Anholt <eric@anholt.net>
> ---
>  drivers/gpu/drm/amd/amdgpu/atom.c               |  2 ++
>  drivers/gpu/drm/ast/ast_fb.c                    |  2 ++
>  drivers/gpu/drm/cirrus/cirrus_fbdev.c           |  1 +
>  drivers/gpu/drm/drm_flip_work.c                 |  1 +
>  drivers/gpu/drm/mgag200/mgag200_fb.c            |  1 +
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c        |  1 +
>  drivers/gpu/drm/omapdrm/omap_fbdev.c            |  1 +
>  drivers/gpu/drm/qxl/qxl_cmd.c                   |  2 ++
>  drivers/gpu/drm/radeon/atom.c                   |  2 ++
>  drivers/gpu/drm/radeon/radeon_legacy_encoders.c |  1 +
>  drivers/gpu/drm/vc4/vc4_drv.h                   |  1 +
>  include/drm/drmP.h                              |  8 -----
>  include/drm/drm_util.h                          | 42 ++++++++++++++++++++++++-
>  13 files changed, 56 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/atom.c b/drivers/gpu/drm/amd/amdgpu/atom.c
> index e9934de1b9cf..dd30f4e61a8c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/atom.c
> +++ b/drivers/gpu/drm/amd/amdgpu/atom.c
> @@ -27,6 +27,8 @@
>  #include <linux/slab.h>
>  #include <asm/unaligned.h>
>  
> +#include <drm/drm_util.h>
> +
>  #define ATOM_DEBUG
>  
>  #include "atom.h"
> diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
> index a80bca1a857f..eb66bf7d3e63 100644
> --- a/drivers/gpu/drm/ast/ast_fb.c
> +++ b/drivers/gpu/drm/ast/ast_fb.c
> @@ -39,7 +39,9 @@
>  #include <drm/drmP.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_fb_helper.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_crtc_helper.h>
> +
>  #include "ast_drv.h"
>  
>  static void ast_dirty_update(struct ast_fbdev *afbdev,
> diff --git a/drivers/gpu/drm/cirrus/cirrus_fbdev.c b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> index 4dd499c7d1ba..79fea1b8bc14 100644
> --- a/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> +++ b/drivers/gpu/drm/cirrus/cirrus_fbdev.c
> @@ -10,6 +10,7 @@
>   */
>  #include <linux/module.h>
>  #include <drm/drmP.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_crtc_helper.h>
>  
> diff --git a/drivers/gpu/drm/drm_flip_work.c b/drivers/gpu/drm/drm_flip_work.c
> index 12dea16f22a8..3da3bf5af405 100644
> --- a/drivers/gpu/drm/drm_flip_work.c
> +++ b/drivers/gpu/drm/drm_flip_work.c
> @@ -22,6 +22,7 @@
>   */
>  
>  #include <drm/drmP.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_flip_work.h>
>  
>  /**
> diff --git a/drivers/gpu/drm/mgag200/mgag200_fb.c b/drivers/gpu/drm/mgag200/mgag200_fb.c
> index 30726c9fe28c..6893934b26c0 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_fb.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_fb.c
> @@ -12,6 +12,7 @@
>   */
>  #include <linux/module.h>
>  #include <drm/drmP.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_crtc_helper.h>
>  
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c
> index 96c2b828dba4..fa2d1d8995ee 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c
> @@ -16,6 +16,7 @@
>   * this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <drm/drm_util.h>
>  
>  #include "mdp5_kms.h"
>  #include "mdp5_smp.h"
> diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> index aee99194499f..851c59f07eb1 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
> @@ -16,6 +16,7 @@
>   */
>  
>  #include <drm/drm_crtc.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_fb_helper.h>
>  
>  #include "omap_drv.h"
> diff --git a/drivers/gpu/drm/qxl/qxl_cmd.c b/drivers/gpu/drm/qxl/qxl_cmd.c
> index dffc5093ff16..2e100f644236 100644
> --- a/drivers/gpu/drm/qxl/qxl_cmd.c
> +++ b/drivers/gpu/drm/qxl/qxl_cmd.c
> @@ -25,6 +25,8 @@
>  
>  /* QXL cmd/ring handling */
>  
> +#include <drm/drm_util.h>
> +
>  #include "qxl_drv.h"
>  #include "qxl_object.h"
>  
> diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
> index e55cbeee7a53..ac98ad561870 100644
> --- a/drivers/gpu/drm/radeon/atom.c
> +++ b/drivers/gpu/drm/radeon/atom.c
> @@ -27,6 +27,8 @@
>  #include <linux/slab.h>
>  #include <asm/unaligned.h>
>  
> +#include <drm/drm_util.h>
> +
>  #define ATOM_DEBUG
>  
>  #include "atom.h"
> diff --git a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
> index 222a1fa41d7c..7e3257e8fd56 100644
> --- a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
> +++ b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
> @@ -24,6 +24,7 @@
>   *          Alex Deucher
>   */
>  #include <drm/drmP.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_crtc_helper.h>
>  #include <drm/radeon_drm.h>
>  #include "radeon.h"
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> index c24b078f0593..2c635f001c71 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.h
> +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> @@ -9,6 +9,7 @@
>  #include <linux/mm_types.h>
>  #include <linux/reservation.h>
>  #include <drm/drmP.h>
> +#include <drm/drm_util.h>
>  #include <drm/drm_encoder.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_atomic.h>
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index 9e47c8dc6b87..bc4cb3732407 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -94,14 +94,6 @@ struct dma_buf_attachment;
>  struct pci_dev;
>  struct pci_controller;
>  
> -/* returns true if currently okay to sleep */
> -static inline bool drm_can_sleep(void)
> -{
> -	if (in_atomic() || in_dbg_master() || irqs_disabled())
> -		return false;
> -	return true;
> -}
> -
>  #if defined(CONFIG_DRM_DEBUG_SELFTEST_MODULE)
>  #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x) EXPORT_SYMBOL(x)
>  #else
> diff --git a/include/drm/drm_util.h b/include/drm/drm_util.h
> index 88abdca89baa..8fda5777471c 100644
> --- a/include/drm/drm_util.h
> +++ b/include/drm/drm_util.h
> @@ -26,7 +26,47 @@
>  #ifndef _DRM_UTIL_H_
>  #define _DRM_UTIL_H_
>  
> -/* helper for handling conditionals in various for_each macros */
> +/**
> + * DOC: drm utils
> + *
> + * Macros and inline functions that does not naturally belong in other places
> + */

The nice new docs here aren't included anywhere. We already have a "Misc
Utilities" in drm-internals.rst, including this there under a "Utilities"
subheading makes sense I think - yes I know, not the most creative name :-)
> +
> +#include <linux/irqflags.h>
> +#include <linux/preempt.h>
> +#include <linux/kgdb.h>
> +#include <linux/smp.h>
> +
> +/**
> + * for_each_if - helper for handling conditionals in various for_each macros
> + * @condition The condition to check
> + *
> + * Typical use:
> + * #define for_each_foo_bar(x, y) \
> + *	list_for_each_entry(x, y->list, head) \
> + *		for_each_if(x->something == SOMETHING)

I think the formatting of this in the html output will look off:
Double-colon plus indenting should fix that.

Merged the first 3 patches of this series thus far.

Thanks, Daniel

> + *
> + * The for_each_if() macro makes the use of for_each_foo_bar() less error
> + * prone.
> + */
>  #define for_each_if(condition) if (!(condition)) {} else
>  
> +/**
> + * drm_can_sleep - returns true if currently okay to sleep
> + *
> + * This function shall not be used in new code.
> + * The check for running in atomic context may not work - see linux/preempt.h.
> + *
> + * FIXME: All users of drm_can_sleep should be removed (see todo.rst)
> + *
> + * Returns:
> + * True if kgdb is active or we are in an atomic context or irqs are disabled
> + */
> +static inline bool drm_can_sleep(void)
> +{
> +	if (in_atomic() || in_dbg_master() || irqs_disabled())
> +		return false;
> +	return true;
> +}
> +
>  #endif
> -- 
> 2.12.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch