# git rev-parse -q --verify 1c27f1fc1549f0e470429f5497a76ad28a37f21a^{commit}
1c27f1fc1549f0e470429f5497a76ad28a37f21a
already have revision, skipping fetch
# git checkout -q -f -B kisskb 1c27f1fc1549f0e470429f5497a76ad28a37f21a
# git clean -qxdf
# < git log -1
# commit 1c27f1fc1549f0e470429f5497a76ad28a37f21a
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Sat Jun 11 10:30:20 2022 -0700
# 
#     iov_iter: fix build issue due to possible type mis-match
#     
#     Commit 6c77676645ad ("iov_iter: Fix iter_xarray_get_pages{,_alloc}()")
#     introduced a problem on some 32-bit architectures (at least arm, xtensa,
#     csky,sparc and mips), that have a 'size_t' that is 'unsigned int'.
#     
#     The reason is that we now do
#     
#         min(nr * PAGE_SIZE - offset, maxsize);
#     
#     where 'nr' and 'offset' and both 'unsigned int', and PAGE_SIZE is
#     'unsigned long'.  As a result, the normal C type rules means that the
#     first argument to 'min()' ends up being 'unsigned long'.
#     
#     In contrast, 'maxsize' is of type 'size_t'.
#     
#     Now, 'size_t' and 'unsigned long' are always the same physical type in
#     the kernel, so you'd think this doesn't matter, and from an actual
#     arithmetic standpoint it doesn't.
#     
#     But on 32-bit architectures 'size_t' is commonly 'unsigned int', even if
#     it could also be 'unsigned long'.  In that situation, both are unsigned
#     32-bit types, but they are not the *same* type.
#     
#     And as a result 'min()' will complain about the distinct types (ignore
#     the "pointer types" part of the error message: that's an artifact of the
#     way we have made 'min()' check types for being the same):
#     
#       lib/iov_iter.c: In function 'iter_xarray_get_pages':
#       include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast [-Werror]
#          20 |         (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
#             |                                   ^~
#       lib/iov_iter.c:1464:16: note: in expansion of macro 'min'
#        1464 |         return min(nr * PAGE_SIZE - offset, maxsize);
#             |                ^~~
#     
#     This was not visible on 64-bit architectures (where we always define
#     'size_t' to be 'unsigned long').
#     
#     Force these cases to use 'min_t(size_t, x, y)' to make the type explicit
#     and avoid the issue.
#     
#     [ Nit-picky note: technically 'size_t' doesn't have to match 'unsigned
#       long' arithmetically. We've certainly historically seen environments
#       with 16-bit address spaces and 32-bit 'unsigned long'.
#     
#       Similarly, even in 64-bit modern environments, 'size_t' could be its
#       own type distinct from 'unsigned long', even if it were arithmetically
#       identical.
#     
#       So the above type commentary is only really descriptive of the kernel
#       environment, not some kind of universal truth for the kinds of wild
#       and crazy situations that are allowed by the C standard ]
#     
#     Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
#     Link: https://lore.kernel.org/all/YqRyL2sIqQNDfky2@debian/
#     Cc: Jeff Layton <jlayton@kernel.org>
#     Cc: David Howells <dhowells@redhat.com>
#     Cc: Al Viro <viro@zeniv.linux.org.uk>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 1c27f1fc1549f0e470429f5497a76ad28a37f21a
# < make -s -j 120 ARCH=powerpc O=/kisskb/build/linus_pmac32_defconfig_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  pmac32_defconfig
# < make -s -j 120 ARCH=powerpc O=/kisskb/build/linus_pmac32_defconfig_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 120 ARCH=powerpc O=/kisskb/build/linus_pmac32_defconfig_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 120 ARCH=powerpc O=/kisskb/build/linus_pmac32_defconfig_powerpc-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/linus_pmac32_defconfig_powerpc-gcc11
# Build took: 0:00:49.113750