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Revert "shced:sem: replace mutex with spinlock"

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Cause we can't do sem_post/wait within spinlock

This reverts commit 23d65cb97f.

Signed-off-by: ligd <liguiding1@xiaomi.com>
This commit is contained in:
ligd 2024-10-24 18:26:00 +08:00 • committed by Xiang Xiao
parent d42f16939e
commit 4541132035
2 changed files with 30 additions and 24 deletions
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7
include/nuttx/rwsem.h
View file

@ -27,15 +27,14 @@
* Included Files
****************************************************************************/
#include <nuttx/semaphore.h>
#include <nuttx/spinlock.h>
#include <nuttx/mutex.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define RWSEM_NO_HOLDER ((pid_t)-1)
#define RWSEM_INITIALIZER {SEM_INITIALIZER(0), \
#define RWSEM_INITIALIZER {NXMUTEX_INITIALIZER, SEM_INITIALIZER(0), \
RWSEM_NO_HOLDER, 0, 0, 0}
/****************************************************************************
@ -44,6 +43,7 @@
typedef struct
{
mutex_t protected; /* Protecting Locks for Read/Write Locked Tables */
sem_t waiting; /* Reader/writer Waiting queue */
pid_t holder; /* The write lock holder, this lock still can be
* locked when the holder is same as the current
@ -52,7 +52,6 @@ typedef struct
int waiter; /* Waiter Count */
int writer; /* Writer Count */
int reader; /* Reader Count */
spinlock_t protected; /* Protecting Locks for Read/Write Locked Tables */
} rw_semaphore_t;
/****************************************************************************

47
sched/semaphore/sem_rw.c
View file

@ -24,7 +24,6 @@
* Included Files
****************************************************************************/
#include <nuttx/irq.h>
#include <nuttx/rwsem.h>
#include <nuttx/sched.h>
#include <assert.h>
@ -66,7 +65,7 @@ static inline void up_wait(FAR rw_semaphore_t *rwsem)
int down_read_trylock(FAR rw_semaphore_t *rwsem)
{
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
/* if the write lock is already held by oneself and since the write lock
* can be recursively held, so, this operation can be converted to a write
@ -81,7 +80,7 @@ int down_read_trylock(FAR rw_semaphore_t *rwsem)
if (rwsem->writer > 0)
{
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
return 0;
}
@ -92,7 +91,7 @@ int down_read_trylock(FAR rw_semaphore_t *rwsem)
rwsem->reader++;
out:
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
return 1;
}
@ -114,7 +113,7 @@ void down_read(FAR rw_semaphore_t *rwsem)
* block and wait for the write-lock to be unlocked.
*/
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
/* if the write lock is already held by oneself and since the write lock
* can be recursively held, so, this operation can be converted to a write
@ -130,9 +129,9 @@ void down_read(FAR rw_semaphore_t *rwsem)
while (rwsem->writer > 0)
{
rwsem->waiter++;
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
nxsem_wait(&rwsem->waiting);
flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
rwsem->waiter--;
}
@ -143,7 +142,7 @@ void down_read(FAR rw_semaphore_t *rwsem)
rwsem->reader++;
out:
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
}
/****************************************************************************
@ -159,7 +158,7 @@ out:
void up_read(FAR rw_semaphore_t *rwsem)
{
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
/* when releasing a read lock and holder is oneself, the read lock is a
* write lock that has been converted, so it should be released according
@ -186,7 +185,7 @@ void up_read(FAR rw_semaphore_t *rwsem)
}
out:
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
}
/****************************************************************************
@ -205,12 +204,13 @@ out:
int down_write_trylock(FAR rw_semaphore_t *rwsem)
{
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
pid_t tid = _SCHED_GETTID();
nxmutex_lock(&rwsem->protected);
if (rwsem->reader > 0 || (rwsem->writer > 0 && tid != rwsem->holder))
{
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
return 0;
}
@ -219,7 +219,7 @@ int down_write_trylock(FAR rw_semaphore_t *rwsem)
rwsem->writer++;
rwsem->holder = tid;
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
return 1;
}
@ -237,15 +237,16 @@ int down_write_trylock(FAR rw_semaphore_t *rwsem)
void down_write(FAR rw_semaphore_t *rwsem)
{
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
pid_t tid = _SCHED_GETTID();
nxmutex_lock(&rwsem->protected);
while (rwsem->reader > 0 || (rwsem->writer > 0 && rwsem->holder != tid))
{
rwsem->waiter++;
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
nxsem_wait(&rwsem->waiting);
flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
rwsem->waiter--;
}
@ -254,7 +255,7 @@ void down_write(FAR rw_semaphore_t *rwsem)
rwsem->writer++;
rwsem->holder = tid;
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
}
/****************************************************************************
@ -270,7 +271,7 @@ void down_write(FAR rw_semaphore_t *rwsem)
void up_write(FAR rw_semaphore_t *rwsem)
{
irqstate_t flags = spin_lock_irqsave(&rwsem->protected);
nxmutex_lock(&rwsem->protected);
DEBUGASSERT(rwsem->writer > 0);
DEBUGASSERT(rwsem->holder == _SCHED_GETTID());
@ -282,7 +283,7 @@ void up_write(FAR rw_semaphore_t *rwsem)
up_wait(rwsem);
spin_unlock_irqrestore(&rwsem->protected, flags);
nxmutex_unlock(&rwsem->protected);
}
/****************************************************************************
@ -306,11 +307,16 @@ int init_rwsem(FAR rw_semaphore_t *rwsem)
/* Initialize structure information */
spin_lock_init(&rwsem->protected);
ret = nxmutex_init(&rwsem->protected);
if (ret < 0)
{
return ret;
}
ret = nxsem_init(&rwsem->waiting, 0, 0);
if (ret < 0)
{
nxmutex_destroy(&rwsem->protected);
return ret;
}
@ -341,5 +347,6 @@ void destroy_rwsem(FAR rw_semaphore_t *rwsem)
DEBUGASSERT(rwsem->waiter == 0 && rwsem->reader == 0 &&
rwsem->writer == 0 && rwsem->holder == RWSEM_NO_HOLDER);
nxmutex_destroy(&rwsem->protected);
nxsem_destroy(&rwsem->waiting);
}