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From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"Sebastian A. Siewior" <bigeasy@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	"Ahmed S. Darwish" <a.darwish@linutronix.de>
Subject: [PATCH v1 3/8] seqlock: Introduce seqcount_latch_t
Date: Thu, 27 Aug 2020 13:40:39 +0200
Message-ID: <20200827114044.11173-4-a.darwish@linutronix.de> (raw)
In-Reply-To: <20200827114044.11173-1-a.darwish@linutronix.de>

Latch sequence counters are a multiversion concurrency control mechanism
where the seqcount_t counter even/odd value is used to switch between
two copies of protected data. This allows the seqcount_t read path to
safely interrupt its write side critical section (e.g. from NMIs).

Initially, latch sequence counters were implemented as a single write
function above plain seqcount_t: raw_write_seqcount_latch(). The read
side was expected to use plain seqcount_t raw_read_seqcount().

A specialized latch read function, raw_read_seqcount_latch(), was later
added. It became the standardized way for latch read paths.  Due to the
dependent load, it has one read memory barrier less than the plain
seqcount_t raw_read_seqcount() API.

Only raw_write_seqcount_latch() and raw_read_seqcount_latch() should be
used with latch sequence counters. Having *unique* read and write path
APIs means that latch sequence counters are actually a data type of
their own -- just inappropriately overloading plain seqcount_t.

Introduce seqcount_latch_t. This adds type-safety and ensures that only
the correct latch-safe APIs are to be used.

Not to break bisection, let the latch APIs also accept plain seqcount_t
or seqcount_raw_spinlock_t. After converting all call sites to
seqcount_latch_t, only that new data type will be allowed.

References: 9b0fd802e8c0 ("seqcount: Add raw_write_seqcount_latch()")
References: 7fc26327b756 ("seqlock: Introduce raw_read_seqcount_latch()")
References: aadd6e5caaac ("time/sched_clock: Use raw_read_seqcount_latch()")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
---
 Documentation/locking/seqlock.rst |  18 ++++++
 include/linux/seqlock.h           | 104 +++++++++++++++++++++---------
 2 files changed, 91 insertions(+), 31 deletions(-)

diff --git a/Documentation/locking/seqlock.rst b/Documentation/locking/seqlock.rst
index 62c5ad98c11c..a334b584f2b3 100644
--- a/Documentation/locking/seqlock.rst
+++ b/Documentation/locking/seqlock.rst
@@ -139,6 +139,24 @@ with the associated LOCKTYPE lock acquired.
 
 Read path: same as in :ref:`seqcount_t`.
 
+
+.. _seqcount_latch_t:
+
+Latch sequence counters (``seqcount_latch_t``)
+----------------------------------------------
+
+Latch sequence counters are a multiversion concurrency control mechanism
+where the embedded seqcount_t counter even/odd value is used to switch
+between two copies of protected data. This allows the sequence counter
+read path to safely interrupt its own write side critical section.
+
+Use seqcount_latch_t when the write side sections cannot be protected
+from interruption by readers. This is typically the case when the read
+side can be invoked from NMI handlers.
+
+Check `raw_write_seqcount_latch()` for more information.
+
+
 .. _seqlock_t:
 
 Sequential locks (``seqlock_t``)
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 962d9768945f..f83fbf2180db 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -587,34 +587,76 @@ static inline void write_seqcount_t_invalidate(seqcount_t *s)
 	kcsan_nestable_atomic_end();
 }
 
-/**
- * raw_read_seqcount_latch() - pick even/odd seqcount_t latch data copy
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+/*
+ * Latch sequence counters (seqcount_latch_t)
+ *
+ * A sequence counter variant where the counter even/odd value is used to
+ * switch between two copies of protected data. This allows the read path,
+ * typically NMIs, to safely interrupt the write side critical section.
  *
- * Use seqcount_t latching to switch between two storage places protected
- * by a sequence counter. Doing so allows having interruptible, preemptible,
- * seqcount_t write side critical sections.
+ * As the write sections are fully preemptible, no special handling for
+ * PREEMPT_RT is needed.
+ */
+typedef struct {
+	seqcount_t seqcount;
+} seqcount_latch_t;
+
+/**
+ * SEQCNT_LATCH_ZERO() - static initializer for seqcount_latch_t
+ * @seq_name: Name of the seqcount_latch_t instance
+ */
+#define SEQCNT_LATCH_ZERO(seq_name) {					\
+	.seqcount		= SEQCNT_ZERO(seq_name.seqcount),	\
+}
+
+/**
+ * seqcount_latch_init() - runtime initializer for seqcount_latch_t
+ * @s: Pointer to the seqcount_latch_t instance
+ */
+static inline void seqcount_latch_init(seqcount_latch_t *s)
+{
+	seqcount_init(&s->seqcount);
+}
+
+/**
+ * raw_read_seqcount_latch() - pick even/odd latch data copy
+ * @s: Pointer to seqcount_t, seqcount_raw_spinlock_t, or seqcount_latch_t
  *
- * Check raw_write_seqcount_latch() for more details and a full reader and
- * writer usage example.
+ * See raw_write_seqcount_latch() for details and a full reader/writer
+ * usage example.
  *
  * Return: sequence counter raw value. Use the lowest bit as an index for
- * picking which data copy to read. The full counter value must then be
- * checked with read_seqcount_retry().
+ * picking which data copy to read. The full counter must then be checked
+ * with read_seqcount_latch_retry().
  */
-#define raw_read_seqcount_latch(s)					\
-	raw_read_seqcount_t_latch(__seqcount_ptr(s))
+#define raw_read_seqcount_latch(s)						\
+({										\
+	/*									\
+	 * Pairs with the first smp_wmb() in raw_write_seqcount_latch().	\
+	 * Due to the dependent load, a full smp_rmb() is not needed.		\
+	 */									\
+	_Generic(*(s),								\
+		 seqcount_t:		  READ_ONCE(((seqcount_t *)s)->sequence),			\
+		 seqcount_raw_spinlock_t: READ_ONCE(((seqcount_raw_spinlock_t *)s)->seqcount.sequence),	\
+		 seqcount_latch_t:	  READ_ONCE(((seqcount_latch_t *)s)->seqcount.sequence));	\
+})
 
-static inline int raw_read_seqcount_t_latch(seqcount_t *s)
+/**
+ * read_seqcount_latch_retry() - end a seqcount_latch_t read section
+ * @s:		Pointer to seqcount_latch_t
+ * @start:	count, from raw_read_seqcount_latch()
+ *
+ * Return: true if a read section retry is required, else false
+ */
+static inline int
+read_seqcount_latch_retry(const seqcount_latch_t *s, unsigned start)
 {
-	/* Pairs with the first smp_wmb() in raw_write_seqcount_latch() */
-	int seq = READ_ONCE(s->sequence); /* ^^^ */
-	return seq;
+	return read_seqcount_retry(&s->seqcount, start);
 }
 
 /**
- * raw_write_seqcount_latch() - redirect readers to even/odd copy
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * raw_write_seqcount_latch() - redirect latch readers to even/odd copy
+ * @s: Pointer to seqcount_t, seqcount_raw_spinlock_t, or seqcount_latch_t
  *
  * The latch technique is a multiversion concurrency control method that allows
  * queries during non-atomic modifications. If you can guarantee queries never
@@ -633,7 +675,7 @@ static inline int raw_read_seqcount_t_latch(seqcount_t *s)
  * The basic form is a data structure like::
  *
  *	struct latch_struct {
- *		seqcount_t		seq;
+ *		seqcount_latch_t	seq;
  *		struct data_struct	data[2];
  *	};
  *
@@ -643,13 +685,13 @@ static inline int raw_read_seqcount_t_latch(seqcount_t *s)
  *	void latch_modify(struct latch_struct *latch, ...)
  *	{
  *		smp_wmb();	// Ensure that the last data[1] update is visible
- *		latch->seq++;
+ *		latch->seq.sequence++;
  *		smp_wmb();	// Ensure that the seqcount update is visible
  *
  *		modify(latch->data[0], ...);
  *
  *		smp_wmb();	// Ensure that the data[0] update is visible
- *		latch->seq++;
+ *		latch->seq.sequence++;
  *		smp_wmb();	// Ensure that the seqcount update is visible
  *
  *		modify(latch->data[1], ...);
@@ -668,8 +710,8 @@ static inline int raw_read_seqcount_t_latch(seqcount_t *s)
  *			idx = seq & 0x01;
  *			entry = data_query(latch->data[idx], ...);
  *
- *		// read_seqcount_retry() includes needed smp_rmb()
- *		} while (read_seqcount_retry(&latch->seq, seq));
+ *		// This includes needed smp_rmb()
+ *		} while (read_seqcount_latch_retry(&latch->seq, seq));
  *
  *		return entry;
  *	}
@@ -693,14 +735,14 @@ static inline int raw_read_seqcount_t_latch(seqcount_t *s)
  *	When data is a dynamic data structure; one should use regular RCU
  *	patterns to manage the lifetimes of the objects within.
  */
-#define raw_write_seqcount_latch(s)					\
-	raw_write_seqcount_t_latch(__seqcount_ptr(s))
-
-static inline void raw_write_seqcount_t_latch(seqcount_t *s)
-{
-       smp_wmb();      /* prior stores before incrementing "sequence" */
-       s->sequence++;
-       smp_wmb();      /* increment "sequence" before following stores */
+#define raw_write_seqcount_latch(s)						\
+{										\
+       smp_wmb();      /* prior stores before incrementing "sequence" */	\
+       _Generic(*(s),								\
+		seqcount_t:		((seqcount_t *)s)->sequence++,		\
+		seqcount_raw_spinlock_t:((seqcount_raw_spinlock_t *)s)->seqcount.sequence++, \
+		seqcount_latch_t:	((seqcount_latch_t *)s)->seqcount.sequence++); \
+       smp_wmb();      /* increment "sequence" before following stores */	\
 }
 
 /*
-- 
2.28.0


  parent reply index

Thread overview: 258+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19 21:45 [PATCH v1 00/25] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 01/25] net: core: device_rename: Use rwsem instead of a seqcount Ahmed S. Darwish
2020-05-19 22:01   ` Stephen Hemminger
2020-05-19 22:23     ` Thomas Gleixner
2020-05-19 23:11       ` Stephen Hemminger
2020-05-19 23:42         ` Thomas Gleixner
2020-05-20  0:06           ` Stephen Hemminger
2020-05-20  1:55             ` Thomas Gleixner
2020-05-20  2:57           ` David Miller
2020-05-20  3:18             ` Eric Dumazet
2020-05-20  4:36               ` Stephen Hemminger
2020-05-20 19:37             ` Thomas Gleixner
2020-05-20 21:36               ` Stephen Hemminger
2020-05-20  2:01   ` Eric Dumazet
2020-05-20  6:42     ` Ahmed S. Darwish
2020-05-20 12:51       ` Eric Dumazet
2020-06-03 14:33         ` Ahmed S. Darwish
2020-05-20 14:37   ` Dan Carpenter
2020-05-25 16:22     ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 02/25] mm/swap: Don't abuse the seqcount latching API Ahmed S. Darwish
2020-05-20 12:22   ` Konstantin Khlebnikov
2020-05-20 13:05     ` Peter Zijlstra
2020-05-22 14:57   ` Peter Zijlstra
2020-05-22 15:17     ` Sebastian A. Siewior
2020-05-22 16:23       ` Peter Zijlstra
2020-05-25 15:24     ` Ahmed S. Darwish
2020-05-25 15:45       ` Peter Zijlstra
2020-05-25 16:10     ` John Ogness
2020-09-10 15:08       ` [tip: locking/core] mm/swap: Do not abuse the seqcount_t " tip-bot2 for Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 03/25] net: phy: fixed_phy: Remove unused seqcount Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 04/25] block: nr_sects_write(): Disable preemption on seqcount write Ahmed S. Darwish
2020-05-22 16:39   ` Peter Zijlstra
2020-05-25  9:56     ` Ahmed S. Darwish
     [not found]   ` <20200522001237.A00E8206BE@mail.kernel.org>
2020-05-25 10:12     ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 05/25] u64_stats: Document writer non-preemptibility requirement Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 06/25] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 07/25] lockdep: Add preemption disabled assertion API Ahmed S. Darwish
2020-05-22 17:55   ` Peter Zijlstra
2020-05-23 14:59     ` Sebastian A. Siewior
2020-05-23 22:41       ` Peter Zijlstra
2020-05-24 10:50         ` Sebastian A. Siewior
2020-05-25 10:22         ` Peter Zijlstra
2020-05-26  0:52           ` Ahmed S. Darwish
2020-05-26  8:13             ` Peter Zijlstra
2020-05-26  9:45               ` Ahmed S. Darwish
2020-06-03 15:30               ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 08/25] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 09/25] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-05-22 18:01   ` Peter Zijlstra
2020-05-22 22:24     ` Steven Rostedt
2020-05-25 10:50       ` Ahmed S. Darwish
2020-05-25 11:02         ` Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 10/25] seqlock: Add RST directives to kernel-doc code samples and notes Ahmed S. Darwish
2020-05-22 18:02   ` Peter Zijlstra
2020-05-22 18:03     ` Peter Zijlstra
2020-05-22 18:26       ` Thomas Gleixner
2020-05-22 18:32         ` Peter Zijlstra
2020-05-25  9:36           ` Ahmed S. Darwish
2020-05-25 13:44             ` Peter Zijlstra
2020-05-25 14:07               ` Peter Zijlstra
2020-05-19 21:45 ` [PATCH v1 11/25] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 12/25] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 13/25] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-05-20 10:48   ` Christian König
2020-05-21  0:09     ` Ahmed S. Darwish
2020-05-21 13:20       ` Christian König
2020-05-19 21:45 ` [PATCH v1 14/25] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 15/25] netfilter: conntrack: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 16/25] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 17/25] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 18/25] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 19/25] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 20/25] raid5: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 21/25] iocost: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 22/25] NFSv4: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 23/25] userfaultfd: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 24/25] kvm/eventfd: " Ahmed S. Darwish
2020-05-19 21:45 ` [PATCH v1 25/25] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-08  0:57 ` [PATCH v2 00/18] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 01/18] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 02/18] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 03/18] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 04/18] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 05/18] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 06/18] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-06-08 14:32     ` Daniel Vetter
2020-06-08  0:57   ` [PATCH v2 07/18] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 08/18] netfilter: conntrack: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 09/18] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 10/18] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 11/18] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 12/18] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 13/18] raid5: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 14/18] iocost: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 15/18] NFSv4: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 16/18] userfaultfd: " Ahmed S. Darwish
2020-06-08  0:57   ` [PATCH v2 17/18] kvm/eventfd: " Ahmed S. Darwish
2020-06-08 12:57     ` Paolo Bonzini
2020-06-08  0:57   ` [PATCH v2 18/18] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-30  5:44 ` [PATCH v3 00/20] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 01/20] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-07-06 21:04     ` Peter Zijlstra
2020-07-06 21:12       ` Jonathan Corbet
2020-07-06 21:16       ` Peter Zijlstra
2020-07-07 10:12       ` Ahmed S. Darwish
2020-07-07 12:47         ` Peter Zijlstra
2020-06-30  5:44   ` [PATCH v3 02/20] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 03/20] seqlock: Add missing kernel-doc annotations Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 04/20] lockdep: Add preemption enabled/disabled assertion APIs Ahmed S. Darwish
2020-07-06 20:50     ` Peter Zijlstra
2020-07-07  7:34       ` Sebastian A. Siewior
2020-06-30  5:44   ` [PATCH v3 05/20] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 06/20] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-06 21:21     ` Peter Zijlstra
2020-07-07  8:40       ` Ahmed S. Darwish
2020-07-07 13:04         ` Peter Zijlstra
2020-07-07 14:37           ` Peter Zijlstra
2020-07-08  9:12             ` Peter Zijlstra
2020-07-08 10:43               ` Ahmed S. Darwish
2020-07-08 10:33             ` Ahmed S. Darwish
2020-07-08 12:29               ` Peter Zijlstra
2020-07-08 14:13                 ` Peter Zijlstra
2020-07-08 14:25                   ` Peter Zijlstra
2020-07-08 15:09                 ` Ahmed S. Darwish
2020-07-08 15:35                   ` Peter Zijlstra
2020-07-08 15:58                     ` Ahmed S. Darwish
2020-07-08 16:16                       ` Peter Zijlstra
2020-07-08 16:18                       ` Peter Zijlstra
2020-07-08 16:01                     ` Peter Zijlstra
2020-06-30  5:44   ` [PATCH v3 07/20] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 08/20] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 09/20] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 10/20] netfilter: conntrack: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 11/20] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 12/20] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 13/20] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 14/20] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 15/20] raid5: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 16/20] iocost: " Ahmed S. Darwish
2020-06-30  7:11     ` Daniel Wagner
2020-06-30  5:44   ` [PATCH v3 17/20] NFSv4: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 18/20] userfaultfd: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 19/20] kvm/eventfd: " Ahmed S. Darwish
2020-06-30  5:44   ` [PATCH v3 20/20] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-20 15:55 ` [PATCH v4 00/24] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 01/24] Documentation: locking: Describe seqlock design and usage Ahmed S. Darwish
2020-07-21  1:35     ` Steven Rostedt
2020-07-21  1:37       ` Steven Rostedt
2020-07-21  5:34       ` Ahmed S. Darwish
2020-07-21  1:44     ` Steven Rostedt
2020-07-21  1:51       ` Steven Rostedt
2020-07-21  7:15         ` Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 02/24] seqlock: Properly format kernel-doc code samples Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 03/24] seqlock: seqcount_t latch: End read sections with read_seqcount_retry() Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 04/24] seqlock: Reorder seqcount_t and seqlock_t API definitions Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 05/24] seqlock: Add kernel-doc for seqcount_t and seqlock_t APIs Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 06/24] seqlock: Implement raw_seqcount_begin() in terms of raw_read_seqcount() Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 07/24] lockdep: Add preemption enabled/disabled assertion APIs Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 08/24] seqlock: lockdep assert non-preemptibility on seqcount_t write Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-08 23:21     ` [PATCH v4 08/24] " Guenter Roeck
2020-08-08 23:23       ` Guenter Roeck
2020-08-09 18:42       ` Ahmed S. Darwish
2020-08-10  8:59         ` Greg KH
2020-08-10  9:48           ` peterz
2020-08-10 10:03             ` Greg KH
2020-08-10  9:54           ` [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write" Ahmed S. Darwish
2020-08-10 10:05             ` Greg KH
2020-08-10 10:35               ` Ahmed S. Darwish
2020-08-10 14:10               ` Guenter Roeck
2020-08-18 22:51                 ` Valdis Klētnieks
2020-08-19  0:56                   ` Guenter Roeck
2020-08-19  7:00                     ` Sebastian Andrzej Siewior
2020-08-19  7:34                       ` Valdis Klētnieks
2020-08-19 16:15                         ` Guenter Roeck
2020-08-10 19:55           ` [PATCH v4 08/24] seqlock: lockdep assert non-preemptibility on seqcount_t write Thomas Gleixner
2020-08-11 10:06             ` Greg KH
2020-07-20 15:55   ` [PATCH v4 09/24] seqlock: Extend seqcount API with associated locks Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 10/24] seqlock: Align multi-line macros newline escapes at 72 columns Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 11/24] dma-buf: Remove custom seqcount lockdep class key Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 12/24] dma-buf: Use sequence counter with associated wound/wait mutex Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 13/24] sched: tasks: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 14/24] netfilter: conntrack: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 15/24] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 16/24] xfrm: policy: Use sequence counters with associated lock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 17/24] timekeeping: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 18/24] vfs: Use sequence counter with associated spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 19/24] raid5: " Ahmed S. Darwish
2020-07-22  6:40     ` Song Liu
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 20/24] iocost: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 21/24] NFSv4: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 22/24] userfaultfd: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 23/24] kvm/eventfd: " Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 15:55   ` [PATCH v4 24/24] hrtimer: Use sequence counter with associated raw spinlock Ahmed S. Darwish
2020-07-29 14:33     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-07-20 16:49   ` [PATCH v4 00/24] seqlock: Extend seqcount API with associated locks Eric Biggers
2020-07-20 17:33     ` Ahmed S. Darwish
2020-08-27 11:40 ` [PATCH v1 0/8] seqlock: Introduce seqcount_latch_t Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 1/8] time/sched_clock: Use raw_read_seqcount_latch() during suspend Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 2/8] mm/swap: Do not abuse the seqcount_t latching API Ahmed S. Darwish
2020-08-27 11:40   ` Ahmed S. Darwish [this message]
2020-09-10 15:08     ` [tip: locking/core] seqlock: Introduce seqcount_latch_t tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 4/8] time/sched_clock: Use seqcount_latch_t Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 5/8] timekeeping: " Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 6/8] x86/tsc: " Ahmed S. Darwish
2020-09-04  7:41     ` peterz
2020-09-04  8:03       ` peterz
2020-09-07 16:29         ` Ahmed S. Darwish
2020-09-07 17:30           ` peterz
2020-09-08  6:23             ` Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 7/8] rbtree_latch: " Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-27 11:40   ` [PATCH v1 8/8] seqlock: seqcount latch APIs: Only allow seqcount_latch_t Ahmed S. Darwish
2020-09-10 15:08     ` [tip: locking/core] " tip-bot2 for Ahmed S. Darwish
2020-08-28  1:07 ` [PATCH v1 0/5] seqlock: Introduce PREEMPT_RT support Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 1/5] seqlock: seqcount_LOCKTYPE_t: Standardize naming convention Ahmed S. Darwish
2020-08-28  8:18     ` peterz
2020-08-28  8:24       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 2/5] seqlock: Use unique prefix for seqcount_t property accessors Ahmed S. Darwish
2020-08-28  8:27     ` peterz
2020-08-28  8:59       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 3/5] seqlock: seqcount_t: Implement all read APIs as statement expressions Ahmed S. Darwish
2020-08-28  8:30     ` peterz
2020-08-28  8:37       ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 4/5] seqlock: seqcount_LOCKTYPE_t: Introduce PREEMPT_RT support Ahmed S. Darwish
2020-08-28  8:57     ` peterz
2020-08-28  8:59     ` peterz
2020-08-28  9:31       ` Ahmed S. Darwish
2020-08-28 14:36         ` Ahmed S. Darwish
2020-08-28  1:07   ` [PATCH v1 5/5] seqlock: PREEMPT_RT: Do not starve seqlock_t writers Ahmed S. Darwish
2020-09-04  6:52   ` [PATCH v1 0/5] seqlock: Introduce PREEMPT_RT support peterz
2020-09-04  7:30     ` Ahmed S. Darwish
2020-09-10 15:08 ` [tip: locking/core] seqlock: seqcount_LOCKNAME_t: " tip-bot2 for Ahmed S. Darwish

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