linux.git, branch master

minmax: simplify min()/max()/clamp() implementation

2024-07-29T03:24:12+00:00

Now that we no longer have any C constant expression contexts (ie array size declarations or static initializers) that use min() or max(), we can simpify the implementation by not having to worry about the result staying as a C constant expression. So now we can unconditionally just use temporary variables of the right type, and get rid of the excessive expansion that used to come from the use of __builtin_choose_expr(__is_constexpr(...), .. to pick the specialized code for constant expressions. Another expansion simplification is to pass the temporary variables (in addition to the original expression) to our __types_ok() macro. That may superficially look like it complicates the macro, but when we only want the type of the expression, expanding the temporary variable names is much simpler and smaller than expanding the potentially complicated original expression. As a result, on my machine, doing a $ time make drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.i goes from real 0m16.621s user 0m15.360s sys 0m1.221s to real 0m2.532s user 0m2.091s sys 0m0.452s because the token expansion goes down dramatically. In particular, the longest line expansion (which was line 71 of that 'ia_css_ynr.host.c' file) shrinks from 23,338kB (yes, 23MB for one single line) to "just" 1,444kB (now "only" 1.4MB). And yes, that line is still the line from hell, because it's doing multiple levels of "min()/max()" expansion thanks to some of them being hidden inside the uDIGIT_FITTING() macro. Lorenzo has a nice cleanup patch that makes that driver use inline functions instead of macros for sDIGIT_FITTING() and uDIGIT_FITTING(), which will fix that line once and for all, but the 16-fold reduction in this case does show why we need to simplify these helpers. Cc: David Laight Cc: Lorenzo Stoakes Signed-off-by: Linus Torvalds

minmax: don't use max() in situations that want a C constant expression

2024-07-29T03:23:27+00:00

We only had a couple of array[] declarations, and changing them to just use 'MAX()' instead of 'max()' fixes the issue. This will allow us to simplify our min/max macros enormously, since they can now unconditionally use temporary variables to avoid using the argument values multiple times. Cc: David Laight Cc: Lorenzo Stoakes Signed-off-by: Linus Torvalds

minmax: scsi: fix mis-use of 'clamp()' in sr.c

2024-07-29T00:06:20+00:00

While working on simplifying the minmax functions, and avoiding excessive macro expansion, it turns out that the sr.c use of the 'clamp()' macro has the arguments the wrong way around. The clamp logic is val = clamp(in, low, high); and it returns the input clamped to the low/high limits. But sr.c ddid speed = clamp(0, speed, 0xffff / 177); which clamps the value '0' to the range '[speed, 0xffff / 177]' and ends up being nonsensical. Happily, I don't think anybody ever cared. Fixes: 9fad9d560af5 ("scsi: sr: Fix unintentional arithmetic wraparound") Cc: Justin Stitt Cc: Kees Cook Cc: Martin K. Petersen Signed-off-by: Linus Torvalds

minmax: make generic MIN() and MAX() macros available everywhere

2024-07-28T22:49:18+00:00

This just standardizes the use of MIN() and MAX() macros, with the very traditional semantics. The goal is to use these for C constant expressions and for top-level / static initializers, and so be able to simplify the min()/max() macros. These macro names were used by various kernel code - they are very traditional, after all - and all such users have been fixed up, with a few different approaches: - trivial duplicated macro definitions have been removed Note that 'trivial' here means that it's obviously kernel code that already included all the major kernel headers, and thus gets the new generic MIN/MAX macros automatically. - non-trivial duplicated macro definitions are guarded with #ifndef This is the "yes, they define their own versions, but no, the include situation is not entirely obvious, and maybe they don't get the generic version automatically" case. - strange use case #1 A couple of drivers decided that the way they want to describe their versioning is with #define MAJ 1 #define MIN 2 #define DRV_VERSION __stringify(MAJ) "." __stringify(MIN) which adds zero value and I just did my Alexander the Great impersonation, and rewrote that pointless Gordian knot as #define DRV_VERSION "1.2" instead. - strange use case #2 A couple of drivers thought that it's a good idea to have a random 'MIN' or 'MAX' define for a value or index into a table, rather than the traditional macro that takes arguments. These values were re-written as C enum's instead. The new function-line macros only expand when followed by an open parenthesis, and thus don't clash with enum use. Happily, there weren't really all that many of these cases, and a lot of users already had the pattern of using '#ifndef' guarding (or in one case just using '#undef MIN') before defining their own private version that does the same thing. I left such cases alone. Cc: David Laight Cc: Lorenzo Stoakes Signed-off-by: Linus Torvalds

Linux 6.11-rc1

2024-07-28T21:19:55+00:00

Merge tag 'kbuild-fixes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-07-28T21:02:48+00:00

Pull Kbuild fixes from Masahiro Yamada: - Fix RPM package build error caused by an incorrect locale setup - Mark modules.weakdep as ghost in RPM package - Fix the odd combination of -S and -c in stack protector scripts, which is an error with the latest Clang * tag 'kbuild-fixes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: Fix '-S -c' in x86 stack protector scripts kbuild: rpm-pkg: ghost modules.weakdep file kbuild: rpm-pkg: Fix C locale setup

minmax: simplify and clarify min_t()/max_t() implementation

2024-07-28T20:50:01+00:00

This simplifies the min_t() and max_t() macros by no longer making them work in the context of a C constant expression. That means that you can no longer use them for static initializers or for array sizes in type definitions, but there were only a couple of such uses, and all of them were converted (famous last words) to use MIN_T/MAX_T instead. Cc: David Laight Cc: Lorenzo Stoakes Signed-off-by: Linus Torvalds

minmax: add a few more MIN_T/MAX_T users

2024-07-28T20:41:14+00:00

Commit 3a7e02c040b1 ("minmax: avoid overly complicated constant expressions in VM code") added the simpler MIN_T/MAX_T macros in order to avoid some excessive expansion from the rather complicated regular min/max macros. The complexity of those macros stems from two issues: (a) trying to use them in situations that require a C constant expression (in static initializers and for array sizes) (b) the type sanity checking and MIN_T/MAX_T avoids both of these issues. Now, in the whole (long) discussion about all this, it was pointed out that the whole type sanity checking is entirely unnecessary for min_t/max_t which get a fixed type that the comparison is done in. But that still leaves min_t/max_t unnecessarily complicated due to worries about the C constant expression case. However, it turns out that there really aren't very many cases that use min_t/max_t for this, and we can just force-convert those. This does exactly that. Which in turn will then allow for much simpler implementations of min_t()/max_t(). All the usual "macros in all upper case will evaluate the arguments multiple times" rules apply. We should do all the same things for the regular min/max() vs MIN/MAX() cases, but that has the added complexity of various drivers defining their own local versions of MIN/MAX, so that needs another level of fixes first. Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.com/ Cc: David Laight Cc: Lorenzo Stoakes Signed-off-by: Linus Torvalds

Merge tag 'ubifs-for-linus-6.11-rc1-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs

2024-07-28T18:51:51+00:00

Pull UBI and UBIFS updates from Richard Weinberger: - Many fixes for power-cut issues by Zhihao Cheng - Another ubiblock error path fix - ubiblock section mismatch fix - Misc fixes all over the place * tag 'ubifs-for-linus-6.11-rc1-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs: ubi: Fix ubi_init() ubiblock_exit() section mismatch ubifs: add check for crypto_shash_tfm_digest ubifs: Fix inconsistent inode size when powercut happens during appendant writing ubi: block: fix null-pointer-dereference in ubiblock_create() ubifs: fix kernel-doc warnings ubifs: correct UBIFS_DFS_DIR_LEN macro definition and improve code clarity mtd: ubi: Restore missing cleanup on ubi_init() failure path ubifs: dbg_orphan_check: Fix missed key type checking ubifs: Fix unattached inode when powercut happens in creating ubifs: Fix space leak when powercut happens in linking tmpfile ubifs: Move ui->data initialization after initializing security ubifs: Fix adding orphan entry twice for the same inode ubifs: Remove insert_dead_orphan from replaying orphan process Revert "ubifs: ubifs_symlink: Fix memleak of inode->i_link in error path" ubifs: Don't add xattr inode into orphan area ubifs: Fix unattached xattr inode if powercut happens after deleting mtd: ubi: avoid expensive do_div() on 32-bit machines mtd: ubi: make ubi_class constant ubi: eba: properly rollback inside self_check_eba

kbuild: Fix '-S -c' in x86 stack protector scripts

2024-07-28T18:47:00+00:00

After a recent change in clang to stop consuming all instances of '-S' and '-c' [1], the stack protector scripts break due to the kernel's use of -Werror=unused-command-line-argument to catch cases where flags are not being properly consumed by the compiler driver: $ echo | clang -o - -x c - -S -c -Werror=unused-command-line-argument clang: error: argument unused during compilation: '-c' [-Werror,-Wunused-command-line-argument] This results in CONFIG_STACKPROTECTOR getting disabled because CONFIG_CC_HAS_SANE_STACKPROTECTOR is no longer set. '-c' and '-S' both instruct the compiler to stop at different stages of the pipeline ('-S' after compiling, '-c' after assembling), so having them present together in the same command makes little sense. In this case, the test wants to stop before assembling because it is looking at the textual assembly output of the compiler for either '%fs' or '%gs', so remove '-c' from the list of arguments to resolve the error. All versions of GCC continue to work after this change, along with versions of clang that do or do not contain the change mentioned above. Cc: stable@vger.kernel.org Fixes: 4f7fd4d7a791 ("[PATCH] Add the -fstack-protector option to the CFLAGS") Fixes: 60a5317ff0f4 ("x86: implement x86_32 stack protector") Link: https://github.com/llvm/llvm-project/commit/6461e537815f7fa68cef06842505353cf5600e9c [1] Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada