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From: Harvey Harrison <harvey.harrison@gmail.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: linux-kernel@vger.kernel.org, sfr@canb.auug.org.au,
	lenb@kernel.org, dhowells@redhat.com, peterz@infradead.org,
	mingo@elte.hu
Subject: Re: Updated generic semaphore patch set
Date: Fri, 14 Mar 2008 14:23:33 -0700	[thread overview]
Message-ID: <1205529813.27712.15.camel@brick> (raw)
In-Reply-To: <20080314204248.GV613@parisc-linux.org>

From: Harvey Harrison <harvey.harrison@gmail.com>
Subject: [PATCH] semaphore: add stubs for kerneldoc to semphore functions

The difference between down/down_trylock/down_interruptable/down_killable
should be expanded to note the difference/use case, a simple stub is added here.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
This applies on top of the last patch I sent, feel free to just use it as
a base for a fuller version.

 kernel/semaphore.c |   37 ++++++++++++++++++++++++++++++++++---
 1 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/kernel/semaphore.c b/kernel/semaphore.c
index bae1017..f48ac5e 100644
--- a/kernel/semaphore.c
+++ b/kernel/semaphore.c
@@ -98,6 +98,12 @@ static noinline void __sched __up(struct semaphore *sem)
 	wake_up_process(waiter->task);
 }
 
+/**
+ * down - acquire the semaphore
+ * @sem: the semaphore to be acquired
+ *
+ * This can be called from interrupt context, unlike mutexes.
+ */
 void down(struct semaphore *sem)
 {
 	unsigned long flags;
@@ -111,6 +117,12 @@ void down(struct semaphore *sem)
 }
 EXPORT_SYMBOL(down);
 
+/**
+ * down_killable - try to acquire the semaphore
+ * @sem: the semaphore to be acquired
+ *
+ * This can be called from interrupt context, unlike mutexes.
+ */
 int down_interruptible(struct semaphore *sem)
 {
 	unsigned long flags;
@@ -127,6 +139,12 @@ int down_interruptible(struct semaphore *sem)
 }
 EXPORT_SYMBOL(down_interruptible);
 
+/**
+ * down_killable - try to acquire the semaphore
+ * @sem: the semaphore to be acquired
+ *
+ * This can be called from interrupt context, unlike mutexes.
+ */
 int down_killable(struct semaphore *sem)
 {
 	unsigned long flags;
@@ -147,7 +165,7 @@ EXPORT_SYMBOL(down_killable);
  * down_trylock - try to acquire the semaphore, without waiting
  * @sem: the semaphore to be acquired
  *
- * Try to acquire the semaphore atomically.  Returns 0 if the mutex has
+ * Try to acquire the semaphore atomically.  Returns 0 if the semaphore has
  * been acquired successfully and 1 if it is contended.
  *
  * NOTE: This return value is inverted from both spin_trylock and
@@ -171,7 +189,14 @@ int down_trylock(struct semaphore *sem)
 }
 EXPORT_SYMBOL(down_trylock);
 
-int down_timeout(struct semaphore *sem, long jiffies)
+/**
+ * down_timeout - try to acquire the semaphore within a timeout
+ * @sem: the semaphore to be acquired
+ * @timeout: the length to wait before timing out, in jiffies
+ *
+ * This can be called from interrupt context, unlike mutexes.
+ */
+int down_timeout(struct semaphore *sem, long timeout)
 {
 	unsigned long flags;
 	int result = 0;
@@ -180,13 +205,19 @@ int down_timeout(struct semaphore *sem, long jiffies)
 	if (likely(sem->count > 0))
 		sem->count--;
 	else
-		result = __down_timeout(sem, jiffies);
+		result = __down_timeout(sem, timeout);
 	spin_unlock_irqrestore(&sem->lock, flags);
 
 	return result;
 }
 EXPORT_SYMBOL(down_timeout);
 
+/**
+ * up - release the semaphore
+ * @sem: the semaphore to be released
+ *
+ * This can be called from interrupt context, unlike mutexes.
+ */
 void up(struct semaphore *sem)
 {
 	unsigned long flags;
-- 
1.5.4.4.684.g0e08




  parent reply	other threads:[~2008-03-14 21:23 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-14 20:42 Updated generic semaphore patch set Matthew Wilcox
2008-03-14 20:44 ` [PATCH 1/6] Fix quota.h includes Matthew Wilcox
2008-03-14 20:44   ` [PATCH 2/6] Add semaphore.h to kernel_lock.c Matthew Wilcox
2008-03-14 20:44     ` [PATCH 3/6] Generic semaphore implementation Matthew Wilcox
2008-03-14 20:44       ` [PATCH 4/6] Introduce down_killable() Matthew Wilcox
2008-03-14 20:44         ` [PATCH 5/6] Add down_timeout and change ACPI to use it Matthew Wilcox
2008-03-14 20:44           ` [PATCH 6/6] Simplify semaphore implementation Matthew Wilcox
2008-03-14 20:59 ` Updated generic semaphore patch set Harvey Harrison
2008-03-14 21:23 ` Harvey Harrison [this message]
2008-03-14 23:37   ` Johannes Weiner

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