[PATCH RFC v5 08/21] dept: Apply Dept to seqlock

[PATCH RFC v5 08/21] dept: Apply Dept to seqlock

[Byungchul Park]

Makes Dept able to track dependencies by seqlock with adding wait
annotation on read side of seqlock.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 include/linux/seqlock.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 37ded6b..585f45c 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -23,6 +23,31 @@
 
 #include <asm/processor.h>
 
+#ifdef CONFIG_DEPT
+#define DEPT_EVT_ALL		((1UL << DEPT_MAX_SUBCLASSES_EVT) - 1)
+#define dept_seq_wait(m, ip)	dept_wait(m, DEPT_EVT_ALL, ip, __func__, 0)
+#define dept_seq_writebegin(m, ip)				\
+do {								\
+	dept_ecxt_enter(m, 1UL, ip, __func__, "write_seqcount_end", 0);\
+	dept_ask_event(m);					\
+} while (0)
+#define dept_seq_writeend(m, ip)				\
+do {								\
+	dept_event(m, 1UL, ip, __func__);			\
+	dept_ecxt_exit(m, 1UL, ip);				\
+} while (0)
+#else
+#define dept_seq_wait(m, ip)		do { } while (0)
+#define dept_seq_writebegin(m, ip)	do { } while (0)
+#define dept_seq_writeend(m, ip)	do { } while (0)
+#endif
+
+#ifdef CONFIG_DEPT
+#define SEQ_DMAP_INIT(lockname) .dmap = { .name = #lockname }
+#else
+#define SEQ_DMAP_INIT(lockname)
+#endif
+
 /*
  * The seqlock seqcount_t interface does not prescribe a precise sequence of
  * read begin/retry/end. For readers, typically there is a call to
@@ -82,7 +107,8 @@ static inline void __seqcount_init(seqcount_t *s, const char *name,
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 # define SEQCOUNT_DEP_MAP_INIT(lockname)				\
-		.dep_map = { .name = #lockname }
+		.dep_map = { .name = #lockname, \
+			     SEQ_DMAP_INIT(lockname) }
 
 /**
  * seqcount_init() - runtime initializer for seqcount_t
@@ -148,7 +174,7 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
  * This lock-unlock technique must be implemented for all of PREEMPT_RT
  * sleeping locks.  See Documentation/locking/locktypes.rst
  */
-#if defined(CONFIG_LOCKDEP) || defined(CONFIG_PREEMPT_RT)
+#if defined(CONFIG_LOCKDEP) || defined(CONFIG_DEPT) || defined(CONFIG_PREEMPT_RT)
 #define __SEQ_LOCK(expr)	expr
 #else
 #define __SEQ_LOCK(expr)
@@ -203,6 +229,22 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
 	__SEQ_LOCK(locktype	*lock);					\
 } seqcount_##lockname##_t;						\
 									\
+static __always_inline void						\
+__seqprop_##lockname##_wait(const seqcount_##lockname##_t *s)		\
+{									\
+	__SEQ_LOCK(dept_seq_wait(&(lockmember)->dep_map.dmap, _RET_IP_));\
+}									\
+									\
+static __always_inline void						\
+__seqprop_##lockname##_writebegin(const seqcount_##lockname##_t *s)	\
+{									\
+}									\
+									\
+static __always_inline void						\
+__seqprop_##lockname##_writeend(const seqcount_##lockname##_t *s)	\
+{									\
+}									\
+									\
 static __always_inline seqcount_t *					\
 __seqprop_##lockname##_ptr(seqcount_##lockname##_t *s)			\
 {									\
@@ -271,6 +313,21 @@ static inline void __seqprop_assert(const seqcount_t *s)
 	lockdep_assert_preemption_disabled();
 }
 
+static inline void __seqprop_wait(seqcount_t *s)
+{
+	dept_seq_wait(&s->dep_map.dmap, _RET_IP_);
+}
+
+static inline void __seqprop_writebegin(seqcount_t *s)
+{
+	dept_seq_writebegin(&s->dep_map.dmap, _RET_IP_);
+}
+
+static inline void __seqprop_writeend(seqcount_t *s)
+{
+	dept_seq_writeend(&s->dep_map.dmap, _RET_IP_);
+}
+
 #define __SEQ_RT	IS_ENABLED(CONFIG_PREEMPT_RT)
 
 SEQCOUNT_LOCKNAME(raw_spinlock, raw_spinlock_t,  false,    s->lock,        raw_spin, raw_spin_lock(s->lock))
@@ -311,6 +368,9 @@ static inline void __seqprop_assert(const seqcount_t *s)
 #define seqprop_sequence(s)		__seqprop(s, sequence)
 #define seqprop_preemptible(s)		__seqprop(s, preemptible)
 #define seqprop_assert(s)		__seqprop(s, assert)
+#define seqprop_dept_wait(s)		__seqprop(s, wait)
+#define seqprop_dept_writebegin(s)	__seqprop(s, writebegin)
+#define seqprop_dept_writeend(s)	__seqprop(s, writeend)
 
 /**
  * __read_seqcount_begin() - begin a seqcount_t read section w/o barrier
@@ -360,6 +420,7 @@ static inline void __seqprop_assert(const seqcount_t *s)
 #define read_seqcount_begin(s)						\
 ({									\
 	seqcount_lockdep_reader_access(seqprop_ptr(s));			\
+	seqprop_dept_wait(s);						\
 	raw_read_seqcount_begin(s);					\
 })
 
@@ -512,6 +573,7 @@ static inline void do_raw_write_seqcount_end(seqcount_t *s)
 		preempt_disable();					\
 									\
 	do_write_seqcount_begin_nested(seqprop_ptr(s), subclass);	\
+	seqprop_dept_writebegin(s);					\
 } while (0)
 
 static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
@@ -538,6 +600,7 @@ static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
 		preempt_disable();					\
 									\
 	do_write_seqcount_begin(seqprop_ptr(s));			\
+	seqprop_dept_writebegin(s);					\
 } while (0)
 
 static inline void do_write_seqcount_begin(seqcount_t *s)
@@ -554,6 +617,7 @@ static inline void do_write_seqcount_begin(seqcount_t *s)
  */
 #define write_seqcount_end(s)						\
 do {									\
+	seqprop_dept_writeend(s);					\
 	do_write_seqcount_end(seqprop_ptr(s));				\
 									\
 	if (seqprop_preemptible(s))					\
-- 
1.9.1

[PATCH RFC v5 08/21] dept: Apply Dept to seqlock

[Byungchul Park]

Makes Dept able to track dependencies by seqlock with adding wait
annotation on read side of seqlock.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 include/linux/seqlock.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 66 insertions(+), 2 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 37ded6b..585f45c 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -23,6 +23,31 @@
 
 #include <asm/processor.h>
 
+#ifdef CONFIG_DEPT
+#define DEPT_EVT_ALL		((1UL << DEPT_MAX_SUBCLASSES_EVT) - 1)
+#define dept_seq_wait(m, ip)	dept_wait(m, DEPT_EVT_ALL, ip, __func__, 0)
+#define dept_seq_writebegin(m, ip)				\
+do {								\
+	dept_ecxt_enter(m, 1UL, ip, __func__, "write_seqcount_end", 0);\
+	dept_ask_event(m);					\
+} while (0)
+#define dept_seq_writeend(m, ip)				\
+do {								\
+	dept_event(m, 1UL, ip, __func__);			\
+	dept_ecxt_exit(m, 1UL, ip);				\
+} while (0)
+#else
+#define dept_seq_wait(m, ip)		do { } while (0)
+#define dept_seq_writebegin(m, ip)	do { } while (0)
+#define dept_seq_writeend(m, ip)	do { } while (0)
+#endif
+
+#ifdef CONFIG_DEPT
+#define SEQ_DMAP_INIT(lockname) .dmap = { .name = #lockname }
+#else
+#define SEQ_DMAP_INIT(lockname)
+#endif
+
 /*
  * The seqlock seqcount_t interface does not prescribe a precise sequence of
  * read begin/retry/end. For readers, typically there is a call to
@@ -82,7 +107,8 @@ static inline void __seqcount_init(seqcount_t *s, const char *name,
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 # define SEQCOUNT_DEP_MAP_INIT(lockname)				\
-		.dep_map = { .name = #lockname }
+		.dep_map = { .name = #lockname, \
+			     SEQ_DMAP_INIT(lockname) }
 
 /**
  * seqcount_init() - runtime initializer for seqcount_t
@@ -148,7 +174,7 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
  * This lock-unlock technique must be implemented for all of PREEMPT_RT
  * sleeping locks.  See Documentation/locking/locktypes.rst
  */
-#if defined(CONFIG_LOCKDEP) || defined(CONFIG_PREEMPT_RT)
+#if defined(CONFIG_LOCKDEP) || defined(CONFIG_DEPT) || defined(CONFIG_PREEMPT_RT)
 #define __SEQ_LOCK(expr)	expr
 #else
 #define __SEQ_LOCK(expr)
@@ -203,6 +229,22 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
 	__SEQ_LOCK(locktype	*lock);					\
 } seqcount_##lockname##_t;						\
 									\
+static __always_inline void						\
+__seqprop_##lockname##_wait(const seqcount_##lockname##_t *s)		\
+{									\
+	__SEQ_LOCK(dept_seq_wait(&(lockmember)->dep_map.dmap, _RET_IP_));\
+}									\
+									\
+static __always_inline void						\
+__seqprop_##lockname##_writebegin(const seqcount_##lockname##_t *s)	\
+{									\
+}									\
+									\
+static __always_inline void						\
+__seqprop_##lockname##_writeend(const seqcount_##lockname##_t *s)	\
+{									\
+}									\
+									\
 static __always_inline seqcount_t *					\
 __seqprop_##lockname##_ptr(seqcount_##lockname##_t *s)			\
 {									\
@@ -271,6 +313,21 @@ static inline void __seqprop_assert(const seqcount_t *s)
 	lockdep_assert_preemption_disabled();
 }
 
+static inline void __seqprop_wait(seqcount_t *s)
+{
+	dept_seq_wait(&s->dep_map.dmap, _RET_IP_);
+}
+
+static inline void __seqprop_writebegin(seqcount_t *s)
+{
+	dept_seq_writebegin(&s->dep_map.dmap, _RET_IP_);
+}
+
+static inline void __seqprop_writeend(seqcount_t *s)
+{
+	dept_seq_writeend(&s->dep_map.dmap, _RET_IP_);
+}
+
 #define __SEQ_RT	IS_ENABLED(CONFIG_PREEMPT_RT)
 
 SEQCOUNT_LOCKNAME(raw_spinlock, raw_spinlock_t,  false,    s->lock,        raw_spin, raw_spin_lock(s->lock))
@@ -311,6 +368,9 @@ static inline void __seqprop_assert(const seqcount_t *s)
 #define seqprop_sequence(s)		__seqprop(s, sequence)
 #define seqprop_preemptible(s)		__seqprop(s, preemptible)
 #define seqprop_assert(s)		__seqprop(s, assert)
+#define seqprop_dept_wait(s)		__seqprop(s, wait)
+#define seqprop_dept_writebegin(s)	__seqprop(s, writebegin)
+#define seqprop_dept_writeend(s)	__seqprop(s, writeend)
 
 /**
  * __read_seqcount_begin() - begin a seqcount_t read section w/o barrier
@@ -360,6 +420,7 @@ static inline void __seqprop_assert(const seqcount_t *s)
 #define read_seqcount_begin(s)						\
 ({									\
 	seqcount_lockdep_reader_access(seqprop_ptr(s));			\
+	seqprop_dept_wait(s);						\
 	raw_read_seqcount_begin(s);					\
 })
 
@@ -512,6 +573,7 @@ static inline void do_raw_write_seqcount_end(seqcount_t *s)
 		preempt_disable();					\
 									\
 	do_write_seqcount_begin_nested(seqprop_ptr(s), subclass);	\
+	seqprop_dept_writebegin(s);					\
 } while (0)
 
 static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
@@ -538,6 +600,7 @@ static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
 		preempt_disable();					\
 									\
 	do_write_seqcount_begin(seqprop_ptr(s));			\
+	seqprop_dept_writebegin(s);					\
 } while (0)
 
 static inline void do_write_seqcount_begin(seqcount_t *s)
@@ -554,6 +617,7 @@ static inline void do_write_seqcount_begin(seqcount_t *s)
  */
 #define write_seqcount_end(s)						\
 do {									\
+	seqprop_dept_writeend(s);					\
 	do_write_seqcount_end(seqprop_ptr(s));				\
 									\
 	if (seqprop_preemptible(s))					\
-- 
1.9.1

Re: [PATCH RFC v5 08/21] dept: Apply Dept to seqlock

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 4410 bytes --]

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
In-Reply-To: <1647397593-16747-9-git-send-email-byungchul.park@lge.com>
References: <1647397593-16747-9-git-send-email-byungchul.park@lge.com>
TO: Byungchul Park <byungchul.park@lge.com>

Hi Byungchul,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on linux/master]
[also build test WARNING on linus/master v5.17-rc8]
[cannot apply to tip/locking/core tip/sched/core hnaz-mm/master next-20220316]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Byungchul-Park/DEPT-Dependency-Tracker/20220316-102853
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2c271fe77d52a0555161926c232cd5bc07178b39
:::::: branch date: 21 hours ago
:::::: commit date: 21 hours ago
config: x86_64-randconfig-m001-20220314 (https://download.01.org/0day-ci/archive/20220317/202203170758.2sBLlrrf-lkp(a)intel.com/config)
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
arch/x86/kvm/x86.c:2129 update_pvclock_gtod() warn: statement has no effect 31

Old smatch warnings:
arch/x86/kvm/x86.c:2845 kvm_end_pvclock_update() warn: statement has no effect 31
arch/x86/kvm/x86.c:5066 kvm_arch_tsc_set_attr() warn: check for integer overflow 'offset'
arch/x86/kvm/x86.c:5107 kvm_vcpu_ioctl_device_attr() error: uninitialized symbol 'r'.

vim +2129 arch/x86/kvm/x86.c

16e8d74d2da992 Marcelo Tosatti 2012-11-27  2101  
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2102  static void update_pvclock_gtod(struct timekeeper *tk)
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2103  {
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2104  	struct pvclock_gtod_data *vdata = &pvclock_gtod_data;
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2105  
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2106  	write_seqcount_begin(&vdata->seq);
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2107  
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2108  	/* copy pvclock gtod data */
b95a8a27c300d1 Thomas Gleixner 2020-02-07  2109  	vdata->clock.vclock_mode	= tk->tkr_mono.clock->vdso_clock_mode;
876e78818def29 Peter Zijlstra  2015-03-19  2110  	vdata->clock.cycle_last		= tk->tkr_mono.cycle_last;
876e78818def29 Peter Zijlstra  2015-03-19  2111  	vdata->clock.mask		= tk->tkr_mono.mask;
876e78818def29 Peter Zijlstra  2015-03-19  2112  	vdata->clock.mult		= tk->tkr_mono.mult;
876e78818def29 Peter Zijlstra  2015-03-19  2113  	vdata->clock.shift		= tk->tkr_mono.shift;
917f9475c0a8ab Paolo Bonzini   2020-01-22  2114  	vdata->clock.base_cycles	= tk->tkr_mono.xtime_nsec;
917f9475c0a8ab Paolo Bonzini   2020-01-22  2115  	vdata->clock.offset		= tk->tkr_mono.base;
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2116  
b95a8a27c300d1 Thomas Gleixner 2020-02-07  2117  	vdata->raw_clock.vclock_mode	= tk->tkr_raw.clock->vdso_clock_mode;
53fafdbb8b21fa Marcelo Tosatti 2019-10-28  2118  	vdata->raw_clock.cycle_last	= tk->tkr_raw.cycle_last;
53fafdbb8b21fa Marcelo Tosatti 2019-10-28  2119  	vdata->raw_clock.mask		= tk->tkr_raw.mask;
53fafdbb8b21fa Marcelo Tosatti 2019-10-28  2120  	vdata->raw_clock.mult		= tk->tkr_raw.mult;
53fafdbb8b21fa Marcelo Tosatti 2019-10-28  2121  	vdata->raw_clock.shift		= tk->tkr_raw.shift;
917f9475c0a8ab Paolo Bonzini   2020-01-22  2122  	vdata->raw_clock.base_cycles	= tk->tkr_raw.xtime_nsec;
917f9475c0a8ab Paolo Bonzini   2020-01-22  2123  	vdata->raw_clock.offset		= tk->tkr_raw.base;
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2124  
55dd00a73a5182 Marcelo Tosatti 2017-01-24  2125  	vdata->wall_time_sec            = tk->xtime_sec;
55dd00a73a5182 Marcelo Tosatti 2017-01-24  2126  
917f9475c0a8ab Paolo Bonzini   2020-01-22  2127  	vdata->offs_boot		= tk->offs_boot;
53fafdbb8b21fa Marcelo Tosatti 2019-10-28  2128  
16e8d74d2da992 Marcelo Tosatti 2012-11-27 @2129  	write_seqcount_end(&vdata->seq);
16e8d74d2da992 Marcelo Tosatti 2012-11-27  2130  }
8171cd68806bd2 Paolo Bonzini   2020-01-22  2131  

---
0-DAY CI Kernel Test Service
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

Re: [PATCH RFC v5 08/21] dept: Apply Dept to seqlock

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 5439 bytes --]

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
In-Reply-To: <1647397593-16747-9-git-send-email-byungchul.park@lge.com>
References: <1647397593-16747-9-git-send-email-byungchul.park@lge.com>
TO: Byungchul Park <byungchul.park@lge.com>

Hi Byungchul,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on linux/master]
[also build test WARNING on linus/master v5.17-rc8]
[cannot apply to tip/locking/core tip/sched/core hnaz-mm/master next-20220317]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Byungchul-Park/DEPT-Dependency-Tracker/20220316-102853
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2c271fe77d52a0555161926c232cd5bc07178b39
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: parisc-randconfig-m031-20220317 (https://download.01.org/0day-ci/archive/20220318/202203180801.CEoECntN-lkp(a)intel.com/config)
compiler: hppa-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
kernel/time/tick-legacy.c:31 legacy_timer_tick() warn: statement has no effect 31
include/linux/u64_stats_sync.h:148 u64_stats_update_end() warn: statement has no effect 31
include/linux/fs.h:907 i_size_write() warn: statement has no effect 31
include/linux/fs.h:907 i_size_write() warn: statement has no effect 31
include/linux/fs.h:907 i_size_write() warn: statement has no effect 31
include/linux/fs.h:907 i_size_write() warn: statement has no effect 31
include/linux/u64_stats_sync.h:174 u64_stats_update_end_irqrestore() warn: statement has no effect 31
include/linux/u64_stats_sync.h:148 u64_stats_update_end() warn: statement has no effect 31
include/linux/u64_stats_sync.h:174 u64_stats_update_end_irqrestore() warn: statement has no effect 31
include/linux/u64_stats_sync.h:148 u64_stats_update_end() warn: statement has no effect 31
include/linux/u64_stats_sync.h:148 u64_stats_update_end() warn: statement has no effect 31
include/linux/u64_stats_sync.h:148 u64_stats_update_end() warn: statement has no effect 31

Old smatch warnings:
fs/gfs2/dir.c:1422 gfs2_dir_read_leaf() error: dereferencing freed memory 'bh'
fs/gfs2/dir.c:1765 dir_new_leaf() warn: passing freed memory 'bh'
fs/gfs2/quota.c:708 gfs2_write_buf_to_page() warn: should 'index << (12 - sdp->sd_sb.sb_bsize_shift)' be a 64 bit type?
fs/gfs2/bmap.c:1248 gfs2_get_extent() warn: should '*extlen << blkbits' be a 64 bit type?
fs/gfs2/bmap.c:1269 gfs2_alloc_extent() warn: should '*extlen << blkbits' be a 64 bit type?
fs/gfs2/bmap.c:1878 punch_hole() error: uninitialized symbol 'end_aligned'.
fs/gfs2/bmap.c:1926 punch_hole() error: uninitialized symbol 'end_aligned'.
net/sched/sch_gred.c:470 gred_change_table_def() warn: potential spectre issue 'table->tab' [w] (local cap)
net/sched/sch_prio.c:216 prio_tune() warn: potential spectre issue 'q->queues' [w] (local cap)
net/sched/sch_cake.c:776 cake_hash() error: buffer overflow 'q->flows' 1024 <= 1030
net/sched/sch_cake.c:788 cake_hash() error: buffer overflow 'q->flows' 1024 <= 1030
net/sched/sch_cake.c:811 cake_hash() error: buffer overflow 'q->hosts' 1024 <= 1030
net/sched/sch_cake.c:814 cake_hash() error: buffer overflow 'q->hosts' 1024 <= 1030
net/sched/sch_cake.c:834 cake_hash() error: buffer overflow 'q->hosts' 1024 <= 1030
net/sched/sch_cake.c:837 cake_hash() error: buffer overflow 'q->hosts' 1024 <= 1030
net/sched/sch_cake.c:1357 cake_overhead() warn: should 'off << 16' be a 64 bit type?

vim +31 kernel/time/tick-legacy.c

b3550164a19d62 Arnd Bergmann 2020-09-24  12  
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  13  /**
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  14   * legacy_timer_tick() - advances the timekeeping infrastructure
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  15   * @ticks:	number of ticks, that have elapsed since the last call.
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  16   *
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  17   * This is used by platforms that have not been converted to
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  18   * generic clockevents.
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  19   *
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  20   * If 'ticks' is zero, the CPU is not handling timekeeping, so
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  21   * only perform process accounting and profiling.
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  22   *
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  23   * Must be called with interrupts disabled.
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  24   */
b3550164a19d62 Arnd Bergmann 2020-09-24  25  void legacy_timer_tick(unsigned long ticks)
b3550164a19d62 Arnd Bergmann 2020-09-24  26  {
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  27  	if (ticks) {
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  28  		raw_spin_lock(&jiffies_lock);
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  29  		write_seqcount_begin(&jiffies_seq);
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24  30  		do_timer(ticks);
56cc7b8acfb7c7 Arnd Bergmann 2020-09-24 @31  		write_seqcount_end(&jiffies_seq);

---
0-DAY CI Kernel Test Service
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org