[PATCH 2/6] drm: add helper for printing to log or seq_file

Rob Clark robdclark at gmail.com
Mon Oct 17 11:59:51 UTC 2016


On Mon, Oct 17, 2016 at 2:38 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Fri, Oct 14, 2016 at 07:55:49PM -0400, Rob Clark wrote:
>> Sometimes it is nice not to duplicate equivalent printk() and
>> seq_printf() code.
>>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>
> Ok, maybe I should wait for coffee to kick in before commenting on patches
> ;-)
>
> Two bits:
> - kerneldoc for this pls, plus pulling into drm-internals.rst.
> - Would be awesome to de-dupe the existing dumping code in drm_mm.c with
>   this.

I have a couple things in drm/msm that I want to de-dup.. and I guess
most drivers probably do as well..

I'm toying with the idea to convert drm_info_list::show over to take a
drm_print ptr instead of seq_file, then we could just re-use the
debugfs fxns directly without having extra wrappers fxns.. question is
best way to do that in a non-flag-day way..

BR,
-R

> -Daniel
>
>> ---
>>  drivers/gpu/drm/Makefile    |  3 ++-
>>  drivers/gpu/drm/drm_print.c | 54 +++++++++++++++++++++++++++++++++++++++
>>  include/drm/drm_print.h     | 62 +++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 118 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/gpu/drm/drm_print.c
>>  create mode 100644 include/drm/drm_print.h
>>
>> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>> index e3dba6f..4894ebb 100644
>> --- a/drivers/gpu/drm/Makefile
>> +++ b/drivers/gpu/drm/Makefile
>> @@ -12,7 +12,8 @@ drm-y       :=      drm_auth.o drm_bufs.o drm_cache.o \
>>               drm_info.o drm_debugfs.o drm_encoder_slave.o \
>>               drm_trace_points.o drm_global.o drm_prime.o \
>>               drm_rect.o drm_vma_manager.o drm_flip_work.o \
>> -             drm_modeset_lock.o drm_atomic.o drm_bridge.o
>> +             drm_modeset_lock.o drm_atomic.o drm_bridge.o \
>> +             drm_print.o
>>
>>  drm-$(CONFIG_COMPAT) += drm_ioc32.o
>>  drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
>> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
>> new file mode 100644
>> index 0000000..ddcb437
>> --- /dev/null
>> +++ b/drivers/gpu/drm/drm_print.c
>> @@ -0,0 +1,54 @@
>> +/*
>> + * Copyright (C) 2016 Red Hat
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
>> + *
>> + * Authors:
>> + * Rob Clark <robdclark at gmail.com>
>> + */
>> +
>> +#include <linux/seq_file.h>
>> +#include <drm/drmP.h>
>> +#include <drm/drm_print.h>
>> +
>> +void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args)
>> +{
>> +     seq_vprintf(p->arg, f, args);
>> +}
>> +
>> +void __drm_printfn_info(struct drm_print *p, const char *f, va_list args)
>> +{
>> +     const char *hdr = KERN_INFO "[" DRM_NAME "] ";
>> +     char fmt[strlen(hdr) + strlen(f) + 1];
>> +
>> +     memcpy(fmt, hdr, strlen(hdr));
>> +     memcpy(fmt + strlen(hdr), f, strlen(f));
>> +     fmt[strlen(hdr) + strlen(f)] = 0;
>> +
>> +     vprintk(fmt, args);
>> +}
>> +
>> +void drm_printf(struct drm_print *p, const char *f, ...)
>> +{
>> +     va_list args;
>> +
>> +     va_start(args, f);
>> +     p->printfn(p, f, args);
>> +     va_end(args);
>> +}
>> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
>> new file mode 100644
>> index 0000000..f294a9a
>> --- /dev/null
>> +++ b/include/drm/drm_print.h
>> @@ -0,0 +1,62 @@
>> +/*
>> + * Copyright (C) 2016 Red Hat
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
>> + *
>> + * Authors:
>> + * Rob Clark <robdclark at gmail.com>
>> + */
>> +
>> +#ifndef DRM_PRINT_H_
>> +#define DRM_PRINT_H_
>> +
>> +#include <stdarg.h>
>> +#include <linux/seq_file.h>
>> +
>> +/* A simple wrapper to abstract seq_file vs printk, so same logging code
>> + * does not have to be duplicated.
>> + */
>> +struct drm_print {
>> +     void (*printfn)(struct drm_print *p, const char *f, va_list args);
>> +     void *arg;
>> +};
>> +
>> +void __drm_printfn_seq_file(struct drm_print *p, const char *f, va_list args);
>> +void __drm_printfn_info(struct drm_print *p, const char *f, va_list args);
>> +
>> +void drm_printf(struct drm_print *p, const char *f, ...);
>> +
>> +static inline struct drm_print drm_print_seq_file(struct seq_file *f)
>> +{
>> +     struct drm_print p = {
>> +             .printfn = __drm_printfn_seq_file,
>> +             .arg = f,
>> +     };
>> +     return p;
>> +}
>> +
>> +static inline struct drm_print drm_print_info(void)
>> +{
>> +     struct drm_print p = {
>> +             .printfn = __drm_printfn_info,
>> +     };
>> +     return p;
>> +}
>> +
>> +#endif /* DRM_PRINT_H_ */
>> --
>> 2.7.4
>>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch


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