linux-stable/include/asm-generic
Linus Torvalds ef0e42a38d asm-generic: qspinlock: fix queued_spin_value_unlocked() implementation
[ Upstream commit 125b0bb95d ]

We really don't want to do atomic_read() or anything like that, since we
already have the value, not the lock.  The whole point of this is that
we've loaded the lock from memory, and we want to check whether the
value we loaded was a locked one or not.

The main use of this is the lockref code, which loads both the lock and
the reference count in one atomic operation, and then works on that
combined value.  With the atomic_read(), the compiler would pointlessly
spill the value to the stack, in order to then be able to read it back
"atomically".

This is the qspinlock version of commit c6f4a90022 ("asm-generic:
ticket-lock: Optimize arch_spin_value_unlocked()") which fixed this same
bug for ticket locks.

Cc: Guo Ren <guoren@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/all/CAHk-=whNRv0v6kQiV5QO6DJhjH4KEL36vWQ6Re8Csrnh4zbRkQ@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-20 15:38:03 +01:00
..
bitops locking/atomic: Make test_and_*_bit() ordered on failure 2022-08-25 11:15:42 +02:00
4level-fixup.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
5level-fixup.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
asm-offsets.h
asm-prototypes.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atomic-instrumented.h locking/atomics: Instrument cmpxchg_double*() 2018-07-25 11:53:59 +02:00
atomic-long.h locking/mutex: Optimize __mutex_trylock_fast() 2018-05-04 10:02:39 +02:00
atomic.h atomics/treewide: Make unconditional inc/dec ops optional 2018-06-21 14:25:24 +02:00
atomic64.h atomics/treewide: Make conditional inc/dec ops optional 2018-06-21 14:25:24 +02:00
audit_change_attr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_dir_write.h audit: Avoid build failures on systems without renameat 2018-01-30 19:07:54 -08:00
audit_read.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_signal.h
audit_write.h audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
barrier.h locking/barriers: Introduce smp_cond_load_relaxed() and atomic_cond_read_relaxed() 2018-04-27 09:48:44 +02:00
bitops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bitsperlong.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
bug.h include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures 2019-07-26 09:14:28 +02:00
cache.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cacheflush.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
checksum.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmpxchg-local.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cmpxchg.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.h time: Add an asm-generic/compat.h file 2018-04-19 13:28:51 +02:00
current.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
delay.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
device.h
div64.h A relatively calm cycle for the docs tree again. 2017-11-13 08:25:06 -08:00
dma-contiguous.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dma-mapping.h dma-mapping: provide a generic dma-noncoherent implementation 2018-05-19 08:46:12 +02:00
dma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
early_ioremap.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
emergency-restart.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
error-injection.h error-injection: Add injectable error types 2018-01-12 17:33:38 -08:00
exec.h mn10300: Remove the architecture 2018-03-09 23:19:56 +01:00
export.h module: use relative references for __ksymtab entries 2018-08-22 10:52:47 -07:00
extable.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fb.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fixmap.h
ftrace.h
futex.h futex: Update comments and docs about return values of arch futex code 2019-07-03 13:14:49 +02:00
getorder.h asm-generic: fix -Wtype-limits compiler warnings 2019-08-25 10:47:58 +02:00
gpio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hardirq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hugetlb.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hw_irq.h
ide_iops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
int-ll64.h int-ll64.h: define u{8,16,32,64} and s{8,16,32,64} based on uapi header 2018-06-07 17:34:38 -07:00
io.h asm-generic: io: Fix ioport_map() for !CONFIG_GENERIC_IOMAP && CONFIG_INDIRECT_PIO 2018-09-14 09:49:21 +01:00
ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_regs.h
irq_work.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irqflags.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kdebug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmap_types.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kprobes.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kvm_para.h KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED 2018-03-06 18:40:44 +01:00
linkage.h
local.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
local64.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mcs_spinlock.h
memory_model.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm-arch-hooks.h
mm_hooks.h arch, mm: Allow arch_dup_mmap() to fail 2017-12-22 20:13:01 +01:00
mmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmu_context.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
msi.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
param.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
parport.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci.h PCI: remove PCI_DMA_BUS_IS_PHYS 2018-05-07 07:15:41 +02:00
pci_iomap.h mn10300: Remove the architecture 2018-03-09 23:19:56 +01:00
percpu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pgalloc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pgtable-nop4d-hack.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
pgtable-nop4d.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
pgtable-nopmd.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
pgtable-nopud.h mm: make the __PAGETABLE_PxD_FOLDED defines non-empty 2018-12-29 13:37:57 +01:00
pgtable.h arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed 2021-11-06 13:58:45 +01:00
preempt.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ptrace.h
qrwlock.h locking/qrwlock: Prevent slowpath writers getting held up by fastpath 2017-10-25 10:57:25 +02:00
qrwlock_types.h locking/qrwlock: include asm/byteorder.h as needed 2018-02-06 10:28:58 +01:00
qspinlock.h asm-generic: qspinlock: fix queued_spin_value_unlocked() implementation 2023-12-20 15:38:03 +01:00
qspinlock_types.h locking/qspinlock: Fix build for anonymous union in older GCC compilers 2018-06-22 04:19:16 +02:00
resource.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rwsem.h Merge branch 'linus' into locking/core, to resolve conflicts 2017-11-07 10:32:44 +01:00
seccomp.h
sections.h asm-generic: sections: refactor memory_intersects 2022-09-05 10:26:32 +02:00
segment.h
serial.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
set_memory.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
signal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
simd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sizes.h
spinlock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
statfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
string.h
switch_to.h mn10300: Remove the architecture 2018-03-09 23:19:56 +01:00
syscall.h
syscalls.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
termios-base.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
termios.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
timex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tlb.h mm/khugepaged: fix GUP-fast interaction by sending IPI 2023-01-18 11:29:59 +01:00
tlbflush.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
topology.h include/asm-generic/topology.h: guard cpumask_of_node() macro argument 2020-06-03 08:19:41 +02:00
trace_clock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
uaccess.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
unaligned.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
unistd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
user.h
vga.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmlinux.lds.h vmlinux.lds.h: Fix placement of '.data..decrypted' section 2022-11-25 17:40:19 +01:00
vtime.h
word-at-a-time.h word-at-a-time: use the same return type for has_zero regardless of endianness 2023-08-11 11:45:36 +02:00
xor.h