| Message ID | 20210303132711.340553449@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm, highmem: Cleanup io/kmap_atomic*() usage | expand |
Am 03.03.21 um 14:20 schrieb Thomas Gleixner: > From: Thomas Gleixner <tglx@linutronix.de> > > There is no reason to disable pagefaults and preemption as a side effect of > kmap_atomic_prot(). > > Use kmap_local_page_prot() instead and document the reasoning for the > mapping usage with the given pgprot. > > Remove the NULL pointer check for the map. These functions return a valid > address for valid pages and the return was bogus anyway as it would have > left preemption and pagefaults disabled. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Christian Koenig <christian.koenig@amd.com> > Cc: Huang Rui <ray.huang@amd.com> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > --- > drivers/gpu/drm/ttm/ttm_bo_util.c | 20 ++++++++++++-------- > 1 file changed, 12 insertions(+), 8 deletions(-) > > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c > @@ -181,13 +181,15 @@ static int ttm_copy_io_ttm_page(struct t > return -ENOMEM; > > src = (void *)((unsigned long)src + (page << PAGE_SHIFT)); > - dst = kmap_atomic_prot(d, prot); > - if (!dst) > - return -ENOMEM; > + /* > + * Ensure that a highmem page is mapped with the correct > + * pgprot. For non highmem the mapping is already there. > + */ I find the comment a bit misleading. Maybe write: /* * Locally map highmem pages with the correct pgprot. * Normal memory should already have the correct pgprot in the linear mapping. */ Apart from that looks good to me. Regards, Christian. > + dst = kmap_local_page_prot(d, prot); > > memcpy_fromio(dst, src, PAGE_SIZE); > > - kunmap_atomic(dst); > + kunmap_local(dst); > > return 0; > } > @@ -203,13 +205,15 @@ static int ttm_copy_ttm_io_page(struct t > return -ENOMEM; > > dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT)); > - src = kmap_atomic_prot(s, prot); > - if (!src) > - return -ENOMEM; > + /* > + * Ensure that a highmem page is mapped with the correct > + * pgprot. For non highmem the mapping is already there. > + */ > + src = kmap_local_page_prot(s, prot); > > memcpy_toio(dst, src, PAGE_SIZE); > > - kunmap_atomic(src); > + kunmap_local(src); > > return 0; > } > >
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -181,13 +181,15 @@ static int ttm_copy_io_ttm_page(struct t return -ENOMEM; src = (void *)((unsigned long)src + (page << PAGE_SHIFT)); - dst = kmap_atomic_prot(d, prot); - if (!dst) - return -ENOMEM; + /* + * Ensure that a highmem page is mapped with the correct + * pgprot. For non highmem the mapping is already there. + */ + dst = kmap_local_page_prot(d, prot); memcpy_fromio(dst, src, PAGE_SIZE); - kunmap_atomic(dst); + kunmap_local(dst); return 0; } @@ -203,13 +205,15 @@ static int ttm_copy_ttm_io_page(struct t return -ENOMEM; dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT)); - src = kmap_atomic_prot(s, prot); - if (!src) - return -ENOMEM; + /* + * Ensure that a highmem page is mapped with the correct + * pgprot. For non highmem the mapping is already there. + */ + src = kmap_local_page_prot(s, prot); memcpy_toio(dst, src, PAGE_SIZE); - kunmap_atomic(src); + kunmap_local(src); return 0; }