[Intel-gfx] [PATCH 2/4] drm: Add dispatcher and driver identification for DRM
Patrik Jakobsson
patrik.jakobsson at linux.intel.com
Wed Jun 10 04:52:33 PDT 2015
On Wed, Jun 10, 2015 at 01:14:20AM +0300, Dmitry V. Levin wrote:
> On Tue, Jun 09, 2015 at 01:26:42PM +0200, Patrik Jakobsson wrote:
> [...]
> > --- a/Makefile.am
> > +++ b/Makefile.am
> > @@ -121,6 +121,7 @@ strace_SOURCES = \
> > utime.c \
> > utimes.c \
> > v4l2.c \
> > + drm.c \
> > vsprintf.c \
> > wait.c \
> > xattr.c
>
> Starting with v4.7-166-g7ae73a9, we keep strace_SOURCES list sorted.
Fixed in v2
>
> > --- /dev/null
> > +++ b/drm.c
> [...]
> > +#include "defs.h"
> > +
> > +#include <sys/types.h>
> > +#include <unistd.h>
> > +#include <string.h>
> > +#include <linux/limits.h>
> > +#include <stdint.h>
> > +#include <sys/ioctl.h>
> > +#include <linux/types.h>
> > +#include <drm.h>
>
> No need to include header files already included by "defs.h".
> Most likely no need to include <linux/limits.h> or <linux/types.h>.
Fixed in v2
>
> > +#define DRM_MAX_NAME_LEN 128
> > +
> > +inline int drm_is_priv(const unsigned int num)
> > +{
> > + return (_IOC_NR(num) >= DRM_COMMAND_BASE &&
> > + _IOC_NR(num) < DRM_COMMAND_END);
> > +}
> > +
> > +static int drm_get_driver_name(struct tcb *tcp, char *name, size_t bufsize)
> > +{
> > + char path[PATH_MAX];
> > + char link[PATH_MAX];
> > + int ret;
> > +
> > + ret = getfdpath(tcp, tcp->u_arg[0], path, PATH_MAX - 1);
> > + if (!ret)
> > + return ret;
> > +
> > + snprintf(link, PATH_MAX, "/sys/class/drm/%s/device/driver",
> > + basename(path));
> > +
> > + ret = readlink(link, path, PATH_MAX - 1);
> > + if (ret < 0)
> > + return ret;
> > +
> > + path[ret] = '\0';
> > + strncpy(name, basename(path), bufsize);
> > +
> > + return 0;
> > +}
> > +
> > +int drm_is_driver(struct tcb *tcp, const char *name)
> > +{
> > + char drv[DRM_MAX_NAME_LEN];
> > + int ret;
> > +
> > + ret = drm_get_driver_name(tcp, drv, DRM_MAX_NAME_LEN);
> > + if (ret)
> > + return 0;
> > +
> > + return strcmp(name, drv) == 0;
> > +}
>
> This interface will result to several getfdpath() calls per
> ioctl_decode(). If the only purpose of drm_is_driver() is to help finding
> the most appropriate function, let's create a table of pairs
> {driver name, function} and pass this table to a function that will do a
> single getfdpath() call, calculate the driver name, and choose the right
> function from the table.
Yes I was thinking the same thing but it's a bit tricky. What I need is:
fd -> path -> driver name. And fd -> path could change between ioctls. It is not
a likely scenario but it's possible. I could get rid of the extra call in
drm_decode_number() if I put it back in drm_ioctl as in my RFC. I could also
optimize path -> driver name with a table but I don't know how expensive those
calls actually are. Not sure what would be the best solution here.
>
> [...]
> > @@ -284,6 +294,7 @@ ioctl_decode(struct tcb *tcp, unsigned int code, long arg)
> > * d sys/des.h (possible overlap)
> > * d vax/dkio.h (possible overlap)
> > * d vaxuba/rxreg.h (possible overlap)
> > + * d drm/drm.h
> > * f sys/filio.h
> > * g sunwindow/win_ioctl.h -no overlap-
> > * g sunwindowdev/winioctl.c !no manifest constant! -no overlap-
>
> This is a history, no need to patch it.
Fixed in v2
>
>
> --
> ldv
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