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

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Oct 17, 2016 at 07:59:51AM -0400, Rob Clark wrote:
> On Mon, Oct 17, 2016 at 2:38 AM, Daniel Vetter <daniel@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@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..

One idea I had in the other reply is to create a seq_file which can dump
to debugfs. Not sure how feasible that is ...
-Daniel

> 
> 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@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@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

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