Re: [PATCH 00/14] Rename dma-buf-map
From: Christian König
Date: Tue Feb 01 2022 - 02:46:30 EST
Am 01.02.22 um 01:36 schrieb Lucas De Marchi:
On Fri, Jan 28, 2022 at 10:48:42AM +0100, Christian König wrote:
Am 28.01.22 um 10:40 schrieb Lucas De Marchi:
On Fri, Jan 28, 2022 at 10:22:00AM +0100, Christian König wrote:
Am 28.01.22 um 10:12 schrieb Lucas De Marchi:
On Fri, Jan 28, 2022 at 09:41:14AM +0100, Christian König wrote:
Rule #1 is to never ever break the build.
Because of this all those patches needs to be squashed into a
single one as far as I can see.
what config are you building on?
Well I'm not building at all, I'm just looking at the patches as an
engineer with 25 years of experience with Linux patches.
Just take a look at patch number 2:
-static int fastrpc_vmap(struct dma_buf *dmabuf, struct dma_buf_map
*map)
+static int fastrpc_vmap(struct dma_buf *dmabuf, struct iosys_map
*map)
You are changing the functions signature without changing any of
the callers.
At bare minimum that causes a warning and on runtime this only
works by coincident now because the structure pointers just happen
to have the same layout. This is not something we usually do.
you missed the magic/hack on patch 1:
1) dma-buf-map.h includes iosys-map.h _at the end_
2) iosys-map.h includes dma-buf-map.h at the beginning
and initially does a "define iosys_map dma_buf_map".
So, it doesn't work by coincidence, It's because it was done to allow
converting it piecemeal.
Oh, my. Please never do stuff like that again.
It's not uncommon approach to be required by other subsystems. Even
drm-intel already used similar approach for macro conversions crossing
drm-intel-next and drm-intel-gt-next branches recently. As I said, I
don't mind one way or the other.
The key point is that you seemed to have a misunderstanding why we
separate changes into functional independent patches.
The goal of that is *not* to reduce the number of lines in a patch, but
rather to reduce the complexity of the review.
When you do an automated renamed with a cocci or sed script you can have
a 100k line patch as result, which is perfectly fine to send out like
this as long as you include the script/commands used to autogenerate the
patch.
The background is that everybody on the planet can generate the patch
with those commands himself and see if the results matches your patch or
not. The maintainer of the component can then just puts an Acked-by on
the patch and move on, but separating the patch causes additional work
for both you as well as the reviewers.
Separating the change into individual patches as much as possible is
nice to have when you do a functional change and want or need a review
from each individual driver maintainer. This is usually the default
case, so sticking with separated changes as much as possible is usually
still the best practice.
Before I go and respin this into a single mega patch, I'd like to gather
some feedback on the following topics:
1) Daniel Vetter and Thomas Zimmermann seemed to be ok with staying with
the current name, dma_buf_map, while you prefer it renamed. Or at
least not make the rename a pre-requisite for the API additions in
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220126203702.1784589-1-lucas.demarchi%40intel.com%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C01142fa3ce484040ade008d9e51aef5d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637792726123940514%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ieMZ9Jiwo%2FQpT5kyyQgHNlepiusN%2Fkfff1Op6TVQ%2BaA%3D&reserved=0
One thing I like about the rename is that it makes clear the separation
between this small shim and dma-buf. There are also some APIs
that are really dma-buf API (e.g. dma_buf_map_attachment()), but if you
don't look carefully you may think it's from dma_buf_map.
Exactly that's the reason why I see this rename as mandatory.
Adding the functionality goes beyond the inter driver interface DMA-buf
provides into driver internal territory and I want to make sure that
people understand just from the name alone that this is not part of
DMA-buf but rather an independent functionality.
2) If renaming, would it still keep the same entry in
MAINTAINERS? Thomas suggested drivers core, but this all seem to be used
mainly on drm/, with just one exception.
I would just add a complete new entry for this and use Thomas as
maintainer (with his permission of course) and dri as mailing list.
3) If renaming, do we have another preferred name?
Nope, as Daniel said the name itself is only bikesheed. What is
important is that we see this as functionality separated from the inter
driver interface.
Regards,
Christian.
thanks
Lucas De Marchi
But as I said, I don't really have a preference. When crossing
subsystems one thing that is hard is that different people have
different
preferences on these things. At least squashing now is much easier than
if I had to split it
Try to imagine how much complain I received on going the other way in
25985edcedea6396277003854657b5f3cb31a628 with
2463 files changed, 4252 insertions(+), 4252 deletions(-)
Well exactly that is perfectly fine.
What you do here is applying your personal hack which is absolutely
not welcomed.
Regards,
Christian.
:)
Lucas De Marchi
Regards,
Christian.
I built this series, full config with
CONFIG_COMPILE_TEST and doing:
git rebase -i <base> -x "make -j$(nproc)"
I split these patches in a way that wouldn't break the build on
purpose.
There were a couple that I couldn't build without cross compiling:
tegra
and rockchip. The others were ok.
I'm not really against squashing everything in one to merge, though.
It will be hard on the conflicts later, but should get the job
done much
quicker.
Lucas De Marchi
Regards,
Christian.
Am 28.01.22 um 09:36 schrieb Lucas De Marchi:
Motivation for this started in
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flkml%2F20220126203702.1784589-1-lucas.demarchi%40intel.com%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C01142fa3ce484040ade008d9e51aef5d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637792726123940514%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=p8rR28Hn0yMTbwy%2F7bpiGyG9fAu9kG1VUzX2MF44mcs%3D&reserved=0
when trying to extend the dma-buf-map API to cover new use
cases: help a
single driver with allocations and sharing code paths for IO and
system
memory. I'm leaving the API additions aside and first renaming the
interface as requested.
There are already some users in tree outside the context of dma-buf
importer/exporter. So before extending the API, let's dissociate
it from
dma-buf.
The iosys-map.h is introduced in the first patch in a way that
allows
the conversion of each driver to happen separately. After all the
conversions are done we can remove the old one, which is the
last patch.
Another possible way is to squash everything and merge together,
but I believe this would make much harder for review.
The conversion was done with the following semantic patch:
@r1@
@@
- struct dma_buf_map
+ struct iosys_map
@r2@
@@
(
- DMA_BUF_MAP_INIT_VADDR
+ IOSYS_MAP_INIT_VADDR
|
- dma_buf_map_set_vaddr
+ iosys_map_set_vaddr
|
- dma_buf_map_set_vaddr_iomem
+ iosys_map_set_vaddr_iomem
|
- dma_buf_map_is_equal
+ iosys_map_is_equal
|
- dma_buf_map_is_null
+ iosys_map_is_null
|
- dma_buf_map_is_set
+ iosys_map_is_set
|
- dma_buf_map_clear
+ iosys_map_clear
|
- dma_buf_map_memcpy_to
+ iosys_map_memcpy_to
|
- dma_buf_map_incr
+ iosys_map_incr
)
@@
@@
- #include <linux/dma-buf-map.h>
+ #include <linux/iosys-map.h>
and then some files had their includes adjusted so we can build
everything on each commit in this series. Also some comments
were update
to remove mentions to dma-buf-map. Simply doing a sed to rename
didn't
work as dma-buf has some APIs using the dma_buf_map prefix.
Once finalized, I think most of this, if not all, could go
through the
drm-misc-next branch. I split i915, msm, nouveau, and radeon in
their
own patches in case it's preferred to take those through their own
trees.
Lucas De Marchi
Lucas De Marchi (14):
iosys-map: Introduce renamed dma-buf-map
misc: fastrpc: Replace dma-buf-map with iosys-map
dma-buf: Replace dma-buf-map with iosys-map
media: Replace dma-buf-map with iosys-map
drm/ttm: Replace dma-buf-map with iosys-map
drm: Replace dma-buf-map with iosys-map in drivers
drm/i915: Replace dma-buf-map with iosys-map
drm/msm: Replace dma-buf-map with iosys-map
drm/nouveau: Replace dma-buf-map with iosys-map
drm/tegra: Replace dma-buf-map with iosys-map
drm/radeon: Replace dma-buf-map with iosys-map
drm: Replace dma-buf-map with iosys-map in common code
Documentation: Refer to iosys-map instead of dma-buf-map
dma-buf-map: Remove API in favor of iosys-map
Documentation/driver-api/dma-buf.rst | 4 +-
Documentation/gpu/todo.rst | 20 +-
MAINTAINERS | 2 +-
drivers/dma-buf/dma-buf.c | 22 +-
drivers/dma-buf/heaps/cma_heap.c | 10 +-
drivers/dma-buf/heaps/system_heap.c | 10 +-
drivers/gpu/drm/ast/ast_drv.h | 2 +-
drivers/gpu/drm/ast/ast_mode.c | 8 +-
drivers/gpu/drm/drm_cache.c | 18 +-
drivers/gpu/drm/drm_client.c | 9 +-
drivers/gpu/drm/drm_fb_helper.c | 12 +-
drivers/gpu/drm/drm_gem.c | 12 +-
drivers/gpu/drm/drm_gem_cma_helper.c | 9 +-
drivers/gpu/drm/drm_gem_framebuffer_helper.c | 16 +-
drivers/gpu/drm/drm_gem_shmem_helper.c | 15 +-
drivers/gpu/drm/drm_gem_ttm_helper.c | 4 +-
drivers/gpu/drm/drm_gem_vram_helper.c | 25 +-
drivers/gpu/drm/drm_internal.h | 6 +-
drivers/gpu/drm/drm_mipi_dbi.c | 8 +-
drivers/gpu/drm/drm_prime.c | 4 +-
drivers/gpu/drm/etnaviv/etnaviv_drv.h | 2 +-
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 8 +-
drivers/gpu/drm/gud/gud_pipe.c | 4 +-
drivers/gpu/drm/hyperv/hyperv_drm_modeset.c | 5 +-
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 8 +-
.../drm/i915/gem/selftests/i915_gem_dmabuf.c | 6 +-
.../gpu/drm/i915/gem/selftests/mock_dmabuf.c | 6 +-
drivers/gpu/drm/lima/lima_gem.c | 3 +-
drivers/gpu/drm/lima/lima_sched.c | 4 +-
drivers/gpu/drm/mediatek/mtk_drm_gem.c | 7 +-
drivers/gpu/drm/mediatek/mtk_drm_gem.h | 5 +-
drivers/gpu/drm/mgag200/mgag200_mode.c | 4 +-
drivers/gpu/drm/msm/msm_drv.h | 4 +-
drivers/gpu/drm/msm/msm_gem_prime.c | 6 +-
drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +
drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 13 +-
drivers/gpu/drm/qxl/qxl_display.c | 8 +-
drivers/gpu/drm/qxl/qxl_draw.c | 6 +-
drivers/gpu/drm/qxl/qxl_drv.h | 10 +-
drivers/gpu/drm/qxl/qxl_object.c | 8 +-
drivers/gpu/drm/qxl/qxl_object.h | 4 +-
drivers/gpu/drm/qxl/qxl_prime.c | 4 +-
drivers/gpu/drm/radeon/radeon_gem.c | 1 +
drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 9 +-
drivers/gpu/drm/rockchip/rockchip_drm_gem.h | 5 +-
drivers/gpu/drm/tegra/gem.c | 10 +-
drivers/gpu/drm/tiny/cirrus.c | 8 +-
drivers/gpu/drm/tiny/gm12u320.c | 7 +-
drivers/gpu/drm/ttm/ttm_bo_util.c | 16 +-
drivers/gpu/drm/ttm/ttm_resource.c | 26 +-
drivers/gpu/drm/ttm/ttm_tt.c | 6 +-
drivers/gpu/drm/udl/udl_modeset.c | 3 +-
drivers/gpu/drm/vboxvideo/vbox_mode.c | 4 +-
drivers/gpu/drm/virtio/virtgpu_prime.c | 1 +
drivers/gpu/drm/vkms/vkms_composer.c | 4 +-
drivers/gpu/drm/vkms/vkms_drv.h | 6 +-
drivers/gpu/drm/vkms/vkms_plane.c | 2 +-
drivers/gpu/drm/vkms/vkms_writeback.c | 2 +-
drivers/gpu/drm/xen/xen_drm_front_gem.c | 7 +-
drivers/gpu/drm/xen/xen_drm_front_gem.h | 6 +-
.../common/videobuf2/videobuf2-dma-contig.c | 8 +-
.../media/common/videobuf2/videobuf2-dma-sg.c | 9 +-
.../common/videobuf2/videobuf2-vmalloc.c | 11 +-
drivers/misc/fastrpc.c | 4 +-
include/drm/drm_cache.h | 6 +-
include/drm/drm_client.h | 7 +-
include/drm/drm_gem.h | 6 +-
include/drm/drm_gem_atomic_helper.h | 6 +-
include/drm/drm_gem_cma_helper.h | 6 +-
include/drm/drm_gem_framebuffer_helper.h | 8 +-
include/drm/drm_gem_shmem_helper.h | 12 +-
include/drm/drm_gem_ttm_helper.h | 6 +-
include/drm/drm_gem_vram_helper.h | 9 +-
include/drm/drm_prime.h | 6 +-
include/drm/ttm/ttm_bo_api.h | 10 +-
include/drm/ttm/ttm_kmap_iter.h | 10 +-
include/drm/ttm/ttm_resource.h | 6 +-
include/linux/dma-buf-map.h | 266
------------------
include/linux/dma-buf.h | 12 +-
include/linux/iosys-map.h | 257
+++++++++++++++++
80 files changed, 579 insertions(+), 552 deletions(-)
delete mode 100644 include/linux/dma-buf-map.h
create mode 100644 include/linux/iosys-map.h