From a5969cabbb4660eab42b6ef0412cbbd1200cf14d Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 12 Oct 2024 07:10:09 +0000
Subject: [PATCH] 修改led为gpio
---
kernel/Documentation/core-api/refcount-vs-atomic.rst | 58 ++++++++++++++++++++++++++++++++++++++--------------------
1 files changed, 38 insertions(+), 20 deletions(-)
diff --git a/kernel/Documentation/core-api/refcount-vs-atomic.rst b/kernel/Documentation/core-api/refcount-vs-atomic.rst
index 322851b..79a009c 100644
--- a/kernel/Documentation/core-api/refcount-vs-atomic.rst
+++ b/kernel/Documentation/core-api/refcount-vs-atomic.rst
@@ -35,7 +35,7 @@
program order (po) relation (on the same CPU). It guarantees that
each ``atomic_*()`` and ``refcount_*()`` operation is atomic and instructions
are executed in program order on a single CPU.
-This is implemented using :c:func:`READ_ONCE`/:c:func:`WRITE_ONCE` and
+This is implemented using READ_ONCE()/WRITE_ONCE() and
compare-and-swap primitives.
A strong (full) memory ordering guarantees that all prior loads and
@@ -44,7 +44,7 @@
It also guarantees that all po-earlier stores on the same CPU
and all propagated stores from other CPUs must propagate to all
other CPUs before any po-later instruction is executed on the original
-CPU (A-cumulative property). This is implemented using :c:func:`smp_mb`.
+CPU (A-cumulative property). This is implemented using smp_mb().
A RELEASE memory ordering guarantees that all prior loads and
stores (all po-earlier instructions) on the same CPU are completed
@@ -52,7 +52,14 @@
stores on the same CPU and all propagated stores from other CPUs
must propagate to all other CPUs before the release operation
(A-cumulative property). This is implemented using
-:c:func:`smp_store_release`.
+smp_store_release().
+
+An ACQUIRE memory ordering guarantees that all post loads and
+stores (all po-later instructions) on the same CPU are
+completed after the acquire operation. It also guarantees that all
+po-later stores on the same CPU must propagate to all other CPUs
+after the acquire operation executes. This is implemented using
+smp_acquire__after_ctrl_dep().
A control dependency (on success) for refcounters guarantees that
if a reference for an object was successfully obtained (reference
@@ -71,8 +78,8 @@
Function changes:
- * :c:func:`atomic_set` --> :c:func:`refcount_set`
- * :c:func:`atomic_read` --> :c:func:`refcount_read`
+ * atomic_set() --> refcount_set()
+ * atomic_read() --> refcount_read()
Memory ordering guarantee changes:
@@ -84,8 +91,8 @@
Function changes:
- * :c:func:`atomic_inc` --> :c:func:`refcount_inc`
- * :c:func:`atomic_add` --> :c:func:`refcount_add`
+ * atomic_inc() --> refcount_inc()
+ * atomic_add() --> refcount_add()
Memory ordering guarantee changes:
@@ -96,7 +103,7 @@
Function changes:
- * :c:func:`atomic_dec` --> :c:func:`refcount_dec`
+ * atomic_dec() --> refcount_dec()
Memory ordering guarantee changes:
@@ -108,8 +115,8 @@
Function changes:
- * :c:func:`atomic_inc_not_zero` --> :c:func:`refcount_inc_not_zero`
- * no atomic counterpart --> :c:func:`refcount_add_not_zero`
+ * atomic_inc_not_zero() --> refcount_inc_not_zero()
+ * no atomic counterpart --> refcount_add_not_zero()
Memory ordering guarantees changes:
@@ -119,32 +126,43 @@
result of obtaining pointer to the object!
-case 5) - decrement-based RMW ops that return a value
------------------------------------------------------
+case 5) - generic dec/sub decrement-based RMW ops that return a value
+---------------------------------------------------------------------
Function changes:
- * :c:func:`atomic_dec_and_test` --> :c:func:`refcount_dec_and_test`
- * :c:func:`atomic_sub_and_test` --> :c:func:`refcount_sub_and_test`
- * no atomic counterpart --> :c:func:`refcount_dec_if_one`
+ * atomic_dec_and_test() --> refcount_dec_and_test()
+ * atomic_sub_and_test() --> refcount_sub_and_test()
+
+Memory ordering guarantees changes:
+
+ * fully ordered --> RELEASE ordering + ACQUIRE ordering on success
+
+
+case 6) other decrement-based RMW ops that return a value
+---------------------------------------------------------
+
+Function changes:
+
+ * no atomic counterpart --> refcount_dec_if_one()
* ``atomic_add_unless(&var, -1, 1)`` --> ``refcount_dec_not_one(&var)``
Memory ordering guarantees changes:
* fully ordered --> RELEASE ordering + control dependency
-.. note:: :c:func:`atomic_add_unless` only provides full order on success.
+.. note:: atomic_add_unless() only provides full order on success.
-case 6) - lock-based RMW
+case 7) - lock-based RMW
------------------------
Function changes:
- * :c:func:`atomic_dec_and_lock` --> :c:func:`refcount_dec_and_lock`
- * :c:func:`atomic_dec_and_mutex_lock` --> :c:func:`refcount_dec_and_mutex_lock`
+ * atomic_dec_and_lock() --> refcount_dec_and_lock()
+ * atomic_dec_and_mutex_lock() --> refcount_dec_and_mutex_lock()
Memory ordering guarantees changes:
* fully ordered --> RELEASE ordering + control dependency + hold
- :c:func:`spin_lock` on success
+ spin_lock() on success
--
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