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locking/arch, x86: Add __down_read_killable() 

Similar to __down_write_killable(), add read killable primitive:
extract current __down_read() code to macros and teach it to get
different functions as slow_path argument:
store ax register to ret, and add sp register and preserve its value.

Add call_rwsem_down_read_failed_killable() assembly entry similar
to call_rwsem_down_read_failed():
push dx register to stack in additional to common registers,
as it's not declarated as modifiable in ____down_read().

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: avagin@virtuozzo.com
Cc: davem@davemloft.net
Cc: fenghua.yu@intel.com
Cc: gorcunov@virtuozzo.com
Cc: heiko.carstens@de.ibm.com
Cc: hpa@zytor.com
Cc: ink@jurassic.park.msu.ru
Cc: mattst88@gmail.com
Cc: rientjes@google.com
Cc: rth@twiddle.net
Cc: schwidefsky@de.ibm.com
Cc: tony.luck@intel.com
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/150670118802.23930.1316107715255410256.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill Tkhai 2017-09-29 19:06:28 +03:00 committed by Ingo Molnar
parent a61ba2c8a4
commit 19c6092301
2 changed files with 37 additions and 10 deletions
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35
arch/x86/include/asm/rwsem.h
View File

@ -60,18 +60,33 @@
/*
* lock for reading
*/
#define ____down_read(sem, slow_path) \
({ \
struct rw_semaphore* ret; \
asm volatile("# beginning down_read\n\t" \
LOCK_PREFIX _ASM_INC "(%[sem])\n\t" \
/* adds 0x00000001 */ \
" jns 1f\n" \
" call " slow_path "\n" \
"1:\n\t" \
"# ending down_read\n\t" \
: "+m" (sem->count), "=a" (ret), \
ASM_CALL_CONSTRAINT \
: [sem] "a" (sem) \
: "memory", "cc"); \
ret; \
})
static inline void __down_read(struct rw_semaphore *sem)
{
asm volatile("# beginning down_read\n\t"
LOCK_PREFIX _ASM_INC "(%[sem])\n\t"
/* adds 0x00000001 */
" jns 1f\n"
" call call_rwsem_down_read_failed\n"
"1:\n\t"
"# ending down_read\n\t"
: "+m" (sem->count)
: [sem] "a" (sem)
: "memory", "cc");
____down_read(sem, "call_rwsem_down_read_failed");
}
static inline int __down_read_killable(struct rw_semaphore *sem)
{
if (IS_ERR(____down_read(sem, "call_rwsem_down_read_failed_killable")))
return -EINTR;
return 0;
}
/*

12
arch/x86/lib/rwsem.S
View File

@ -98,6 +98,18 @@ ENTRY(call_rwsem_down_read_failed)
ret
ENDPROC(call_rwsem_down_read_failed)
ENTRY(call_rwsem_down_read_failed_killable)
FRAME_BEGIN
save_common_regs
__ASM_SIZE(push,) %__ASM_REG(dx)
movq %rax,%rdi
call rwsem_down_read_failed_killable
__ASM_SIZE(pop,) %__ASM_REG(dx)
restore_common_regs
FRAME_END
ret
ENDPROC(call_rwsem_down_read_failed_killable)
ENTRY(call_rwsem_down_write_failed)
FRAME_BEGIN
save_common_regs