On Mon, Oct 17, 2022 at 05:37:23PM +0800, Zhao Liu wrote: > From: Zhao Liu <zhao1.liu@xxxxxxxxx> > > The use of kmap_atomic() is being deprecated in favor of > kmap_local_page()[1]. > > The main difference between atomic and local mappings is that local > mappings doesn't disable page faults or preemption. > > In drm/i915/gt/uc/intel_us_fw.c, the function intel_uc_fw_copy_rsa() > just use the mapping to do memory copy so it doesn't need to disable > pagefaults and preemption for mapping. Thus the local mapping without > atomic context (not disable pagefaults / preemption) is enough. > > Therefore, intel_uc_fw_copy_rsa() is a function where the use of > memcpy_from_page() with kmap_local_page() in place of memcpy() with > kmap_atomic() is correctly suited. > > Convert the calls of memcpy() with kmap_atomic() / kunmap_atomic() to > memcpy_from_page() which uses local mapping to copy. > > [1]: https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@xxxxxxxxx/T/#u > > Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Suggested-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx> > Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx> > --- > Suggested by credits: > Ira: Referred to his task document and suggestions about using > memcpy_from_page() directly. > Fabio: Referred to his boiler plate commit message. > --- > drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > index b91ad4aede1f..64d56f175d32 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > @@ -962,16 +962,13 @@ size_t intel_uc_fw_copy_rsa(struct intel_uc_fw *uc_fw, void *dst, u32 max_len) > > for_each_sgt_page(page, iter, uc_fw->obj->mm.pages) { > u32 len = min_t(u32, size, PAGE_SIZE - offset); > - void *vaddr; > > if (idx > 0) { > idx--; > continue; > } > > - vaddr = kmap_atomic(page); > - memcpy(dst, vaddr + offset, len); > - kunmap_atomic(vaddr); > + memcpy_from_page(dst, page, offset, len); > > offset = 0; > dst += len; > -- > 2.34.1 >
