Buildresult: linus/um-defconfig/um-x86_64 built on Jul 4 2022, 10:27

kisskb

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Status:	OK
Date/Time:	Jul 4 2022, 10:27
Duration:	0:00:24.237402
Builder:	ka7
Revision:	lockref: remove unused 'lockref_get_or_lock()' function (`b8d5109f50969ead9d49c3e8bd78ec1f82e548e3)`
Target:	linus/um-defconfig/um-x86_64
Branch:	linus
Compiler:	um-x86_64 (x86_64-linux-gcc.br_real (Buildroot 2017.05) 5.4.0 / GNU ld (GNU Binutils) 2.27)
Config:	defconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify b8d5109f50969ead9d49c3e8bd78ec1f82e548e3^{commit} b8d5109f50969ead9d49c3e8bd78ec1f82e548e3 already have revision, skipping fetch # git checkout -q -f -B kisskb b8d5109f50969ead9d49c3e8bd78ec1f82e548e3 # git clean -qxdf # < git log -1 # commit b8d5109f50969ead9d49c3e8bd78ec1f82e548e3 # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Sun Jul 3 14:40:28 2022 -0700 # # lockref: remove unused 'lockref_get_or_lock()' function # # Looking at the conditional lock acquire functions in the kernel due to # the new sparse support (see commit 4a557a5d1a61 "sparse: introduce # conditional lock acquire function attribute"), it became obvious that # the lockref code has a couple of them, but they don't match the usual # naming convention for the other ones, and their return value logic is # also reversed. # # In the other very similar places, the naming pattern is '_and_lock()' # (eg 'atomic_put_and_lock()' and 'refcount_dec_and_lock()'), and the # function returns true when the lock is taken. # # The lockref code is superficially very similar to the refcount code, # only with the special "atomic wrt the embedded lock" semantics. But # instead of the '_and_lock()' naming it uses '_or_lock()'. # # And instead of returning true in case it took the lock, it returns true # if it didn't* take the lock. # # Now, arguably the reflock code is quite logical: it really is a "either # decrement _or_ lock" kind of situation - and the return value is about # whether the operation succeeded without any special care needed. # # So despite the similarities, the differences do make some sense, and # maybe it's not worth trying to unify the different conditional locking # primitives in this area. # # But while looking at this all, it did become obvious that the # 'lockref_get_or_lock()' function hasn't actually had any users for # almost a decade. # # The only user it ever had was the shortlived 'd_rcu_to_refcount()' # function, and it got removed and replaced with 'lockref_get_not_dead()' # back in 2013 in commits 0d98439ea3c6 ("vfs: use lockred 'dead' flag to # mark unrecoverably dead dentries") and e5c832d55588 ("vfs: fix dentry # RCU to refcounting possibly sleeping dput()") # # In fact, that single use was removed less than a week after the whole # function was introduced in commit b3abd80250c1 ("lockref: add # 'lockref_get_or_lock() helper") so this function has been around for a # decade, but only had a user for six days. # # Let's just put this mis-designed and unused function out of its misery. # # We can think about the naming and semantic oddities of the remaining # 'lockref_put_or_lock()' later, but at least that function has users. # # And while the naming is different and the return value doesn't match, # that function matches the whole '{atomic,refcount}_dec_and_test()' # pattern much better (ie the magic happens when the count goes down to # zero, not when it is incremented from zero). # # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 b8d5109f50969ead9d49c3e8bd78ec1f82e548e3 # < make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 defconfig # < make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 help # make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 olddefconfig # make -s -j 32 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 LINK linux Completed OK # rm -rf /kisskb/build/linus_um-defconfig_um-x86_64 # Build took: 0:00:24.237402

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