# 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 # 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 # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux-ld --version # < git log --format=%s --max-count=1 b8d5109f50969ead9d49c3e8bd78ec1f82e548e3 # < make -s -j 40 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- sun3_defconfig arch/m68k/configs/sun3_defconfig:37:warning: symbol value 'm' invalid for ZPOOL # < make -s -j 40 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- help # make -s -j 40 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- olddefconfig # make -s -j 40 ARCH=m68k O=/kisskb/build/linus_sun3_defconfig_m68k-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/m68k-linux/bin/m68k-linux- In file included from /kisskb/src/include/linux/string.h:20, from /kisskb/src/include/linux/bitmap.h:11, from /kisskb/src/include/linux/cpumask.h:12, from /kisskb/src/include/linux/mm_types_task.h:14, from /kisskb/src/include/linux/mm_types.h:5, from /kisskb/src/include/linux/buildid.h:5, from /kisskb/src/include/linux/module.h:14, from /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:32: In function 'check586', inlined from 'sun3_82586_probe1' at /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:365:6, inlined from 'sun3_82586_probe' at /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:311:8: /kisskb/src/arch/m68k/include/asm/string.h:68:25: warning: '__builtin_memset' offset [0, 11] is out of the bounds [0, 0] [-Warray-bounds] 68 | #define memset(d, c, n) __builtin_memset(d, c, n) | ^~~~~~~~~~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:218:9: note: in expansion of macro 'memset' 218 | memset((char *)p->scp,0, sizeof(struct scp_struct)); | ^~~~~~ In file included from /kisskb/src/include/linux/swab.h:5, from /kisskb/src/include/uapi/linux/byteorder/big_endian.h:14, from /kisskb/src/include/linux/byteorder/big_endian.h:5, from /kisskb/src/arch/m68k/include/uapi/asm/byteorder.h:5, from /kisskb/src/include/asm-generic/bitops/le.h:6, from /kisskb/src/arch/m68k/include/asm/bitops.h:529, from /kisskb/src/include/linux/bitops.h:33, from /kisskb/src/include/linux/kernel.h:22, from /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:31: /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c: In function 'sun3_82586_timeout': /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:989:122: warning: array subscript 1 is above array bounds of 'volatile struct transmit_cmd_struct *[1]' [-Warray-bounds] 989 | printk("%s: command-stats: %04x %04x\n",dev->name,swab16(p->xmit_cmds[0]->cmd_status),swab16(p->xmit_cmds[1]->cmd_status)); | ~~~~~~~~~~~~^~~ /kisskb/src/include/uapi/linux/swab.h:107:19: note: in definition of macro '__swab16' 107 | __fswab16(x)) | ^ /kisskb/src/include/linux/printk.h:464:26: note: in expansion of macro 'printk_index_wrap' 464 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__) | ^~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:989:17: note: in expansion of macro 'printk' 989 | printk("%s: command-stats: %04x %04x\n",dev->name,swab16(p->xmit_cmds[0]->cmd_status),swab16(p->xmit_cmds[1]->cmd_status)); | ^~~~~~ /kisskb/src/drivers/net/ethernet/i825xx/sun3_82586.c:155:46: note: while referencing 'xmit_cmds' 155 | volatile struct transmit_cmd_struct *xmit_cmds[NUM_XMIT_BUFFS]; | ^~~~~~~~~ Completed OK # rm -rf /kisskb/build/linus_sun3_defconfig_m68k-gcc11 # Build took: 0:01:02.134589