# git gc
# git rev-parse -q --verify 7a7fd0de4a9804299793e564a555a49c1fc924cb^{commit}
7a7fd0de4a9804299793e564a555a49c1fc924cb
already have revision, skipping fetch
# git checkout -q -f -B kisskb 7a7fd0de4a9804299793e564a555a49c1fc924cb
# git clean -qxdf
# < git log -1
# commit 7a7fd0de4a9804299793e564a555a49c1fc924cb
# Merge: c608aca57dd0 80cc83842394
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Mon Mar 1 11:24:18 2021 -0800
# 
#     Merge branch 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
#     
#     Pull kmap conversion updates from David Sterba:
#      "This contains changes regarding kmap API use and eg conversion from
#       kmap_atomic to kmap_local_page.
#     
#       The API belongs to memory management but to save cross-tree
#       dependency headaches we've agreed to take it through the btrfs tree
#       because there are some trivial conversions possible, while the rest
#       will need some time and getting the easy cases out of the way would be
#       convenient.
#     
#       The changes can be grouped:
#     
#        - function exports, new helpers
#     
#        - new VM_BUG_ON for additional verification; it's been discussed if
#          it should be VM_BUG_ON or BUG_ON, the former was chosen due to
#          performance reasons
#     
#        - code replaced by relevant helpers"
#     
#     [ This is an updated version of a request that originally came in during
#       the merge window, but I asked for some updates:
#     
#         https://lore.kernel.org/lkml/cover.1614090658.git.dsterba@suse.com/
#     
#       which is why this got merge after the merge window closed.  - Linus ]
#     
#     * 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
#       btrfs: use copy_highpage() instead of 2 kmaps()
#       btrfs: use memcpy_[to|from]_page() and kmap_local_page()
#       mm/highmem: Add VM_BUG_ON() to mem*_page() calls
#       mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page()
#       mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page()
#       mm/highmem: Lift memcpy_[to|from]_page to core
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 7a7fd0de4a9804299793e564a555a49c1fc924cb
# < make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  x86_64_defconfig
# < make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  help
# make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  olddefconfig
# make -s -j 32 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/x86_64-linux/bin/x86_64-linux-  
Completed OK
# rm -rf /kisskb/build/linus_x86_64_defconfig_x86_64-gcc8
# Build took: 0:07:50.847487