On Mon, Aug 15, 2016 at 04:13:54PM +0300, Jani Nikula wrote: > On Mon, 15 Aug 2016, Eric Engestrom <eric.engestrom@xxxxxxxxxx> wrote: > > On Mon, Aug 15, 2016 at 12:54:01PM +0300, Jani Nikula wrote: > >> On Mon, 15 Aug 2016, Eric Engestrom <eric@xxxxxxxxxxxx> wrote: > >> > Signed-off-by: Eric Engestrom <eric@xxxxxxxxxxxx> > >> > --- > >> > > >> > I moved the main bits to be the first diffs, shouldn't affect anything > >> > when applying the patch, but I wanted to ask: > >> > I don't like the hard-coded `32` the appears in both kmalloc() and > >> > snprintf(), what do you think? If you don't like it either, what would > >> > you suggest? Should I #define it? > >> > > >> > Second question is about the patch mail itself: should I send this kind > >> > of patch separated by module, with a note requesting them to be squashed > >> > when applying? It has to land as a single patch, but for review it might > >> > be easier if people only see the bits they each care about, as well as > >> > to collect ack's/r-b's. > >> > > >> > Cheers, > >> > Eric > >> > > >> > --- > >> > drivers/gpu/drm/amd/amdgpu/dce_v10_0.c | 6 ++-- > >> > drivers/gpu/drm/amd/amdgpu/dce_v11_0.c | 6 ++-- > >> > drivers/gpu/drm/amd/amdgpu/dce_v8_0.c | 6 ++-- > >> > drivers/gpu/drm/drm_atomic.c | 5 ++-- > >> > drivers/gpu/drm/drm_crtc.c | 21 ++++++++----- > >> > drivers/gpu/drm/drm_fourcc.c | 17 ++++++----- > >> > drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c | 6 ++-- > >> > drivers/gpu/drm/i915/i915_debugfs.c | 11 ++++++- > >> > drivers/gpu/drm/i915/intel_atomic_plane.c | 6 ++-- > >> > drivers/gpu/drm/i915/intel_display.c | 39 ++++++++++++++++--------- > >> > drivers/gpu/drm/radeon/atombios_crtc.c | 12 +++++--- > >> > include/drm/drm_fourcc.h | 2 +- > >> > 12 files changed, 89 insertions(+), 48 deletions(-) > >> > > >> > diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c > >> > index 0645c85..38216a1 100644 > >> > --- a/drivers/gpu/drm/drm_fourcc.c > >> > +++ b/drivers/gpu/drm/drm_fourcc.c > >> > @@ -39,16 +39,14 @@ static char printable_char(int c) > >> > * drm_get_format_name - return a string for drm fourcc format > >> > * @format: format to compute name of > >> > * > >> > - * Note that the buffer used by this function is globally shared and owned by > >> > - * the function itself. > >> > - * > >> > - * FIXME: This isn't really multithreading safe. > >> > + * Note that the buffer returned by this function is owned by the caller > >> > + * and will need to be freed. > >> > */ > >> > const char *drm_get_format_name(uint32_t format) > >> > >> I find it surprising that a function that allocates a buffer returns a > >> const pointer. Some userspace libraries have conventions about the > >> ownership based on constness. > >> > >> (I also find it suprising that kfree() takes a const pointer; arguably > >> that call changes the memory.) > >> > >> Is there precedent for this? > >> > >> BR, > >> Jani. > > > > It's not a const pointer, it's a normal pointer to a const char, i.e. > > you can do as you want with the pointer but you shouldn't change the > > chars it points to. > > Ermh, that's what I meant even if I was sloppy in my reply. And arguably > freeing the bytes the pointer points at changes them, albeit subtly. And > having a function return a pointer to const data is often an indication > that the ownership of the data isn't transfered, i.e. you're not > supposed to free it yourself. I already applied the patch, but yes dropping the const would be a good hint to callers that they now own that block of memory. Eric, can you pls follow up with a fix up patch - drm-misc is non-rebasing? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
