LinuxKPI: Import linux_page.c and some dependent code from drm-kmod
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Authored by wulf on Sep 27 2021, 11:26 PM.

Details

Reviewers

• hselasky
manu
markj

Commits

rGe1f5bed753fe: LinuxKPI: Import linux_page.c and some dependent code from drm-kmod
rGc072f6e856bc: LinuxKPI: Import linux_page.c and some dependent code from drm-kmod

Summary

No functional changes intended

Diff Detail

Repository

rG FreeBSD src repository

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

wulf created this revision.Sep 27 2021, 11:26 PM

Herald added subscribers: linuxkpi, emaste, imp. · View Herald TranscriptSep 27 2021, 11:26 PM

wulf requested review of this revision.Sep 27 2021, 11:26 PM

Harbormaster completed remote builds in B41791: Diff 95801.Sep 27 2021, 11:26 PM

bz added a reviewer: markj.Sep 27 2021, 11:44 PM

bz added a subscriber: bz.

bz added inline comments.

sys/compat/linuxkpi/common/include/linux/scatterlist.h
568	Do you need to use kmap/kunmap here or can you not just pin the entire loop and us sf_* directly as done above?
sys/compat/linuxkpi/common/src/linux_page.c
71	Is this PMAP_HAS_DMAP now?
425	Probably %s: func better here now or rather remove this entirely as we don't have a LINUX_VERBOSE_DEBUG?

wulf added inline comments.Sep 28 2021, 12:55 AM

sys/compat/linuxkpi/common/include/linux/scatterlist.h
568	kmap/kunmap expands to NO-OP on most of supported archs
sys/compat/linuxkpi/common/src/linux_page.c
71	Looks like that

Use PMAP_HAS_DMAP instead of LP64
Optimize sg_pcopy_to_buffer() for !PMAP_HAS_DMAP case
Move kmap/kunmap implementation in to header file
Drop debugging printf

Harbormaster completed remote builds in B41806: Diff 95825.Sep 28 2021, 8:49 AM

wulf marked 3 inline comments as done.Sep 28 2021, 8:53 AM

wulf added inline comments.

sys/compat/linuxkpi/common/include/linux/scatterlist.h
568	Do you need to use kmap/kunmap here or can you not just pin the entire loop and us sf_* directly as done above? loop is rewritten to use pin/unpin and sf_* directly
sys/compat/linuxkpi/common/src/linux_page.c
425	Probably %s: func better here now or rather remove this entirely as we don't have a LINUX_VERBOSE_DEBUG? debugging stuff removed

Thanks a lot, that's something I wanted to do for a long time.

This revision is now accepted and ready to land.Sep 28 2021, 9:07 AM

Looks good. Just make sure "make buildkernel WITH_OFED=YES" passes.

markj added inline comments.Sep 28 2021, 5:15 PM

sys/compat/linuxkpi/common/include/linux/scatterlist.h
566	`min()` will truncate parameters to unsigned int. I guess it should be `ulmin()`.
sys/compat/linuxkpi/common/src/linux_page.c
352	We always start at pindex 0, so `holebegin` is ignored. I understand that this may provide the desired semantics (or is it a bug?) but it looks wrong and deserves a comment IMHO.
361	Which vm_object_reference() call does this pair with?

wulf marked an inline comment as done.Sep 28 2021, 6:28 PM

wulf added inline comments.

sys/compat/linuxkpi/common/src/linux_page.c
361	It lies in linux_file_mmap_single() in `sys/compat/linuxkpi/common/src/linux_compat.c` (through cdev_pager_allocate() call). This routine is destructor for it.