Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation

From: Ingo Molnar
Date: Tue Dec 13 2005 - 04:55:37 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> all this simplified the 'compatibility conversion' to the patch below.
> No other non-generic changes are needed.

there were 3 more patches needed, which convert some semaphores to
completions:

sx8-sem2completions.patch
cpu5wdt-sem2completions.patch
ide-gendev-sem-to-completion.patch

all attached.

Ingo
drivers/block/sx8.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)

Index: linux/drivers/block/sx8.c
===================================================================
--- linux.orig/drivers/block/sx8.c
+++ linux/drivers/block/sx8.c
@@ -27,6 +27,7 @@
#include <linux/time.h>
#include <linux/hdreg.h>
#include <linux/dma-mapping.h>
+#include <linux/completion.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
@@ -303,7 +304,7 @@ struct carm_host {

struct work_struct fsm_task;

- struct semaphore probe_sem;
+ struct completion probe_comp;
};

struct carm_response {
@@ -1365,7 +1366,7 @@ static void carm_fsm_task (void *_data)
}

case HST_PROBE_FINISHED:
- up(&host->probe_sem);
+ complete(&host->probe_comp);
break;

case HST_ERROR:
@@ -1641,7 +1642,7 @@ static int carm_init_one (struct pci_dev
host->flags = pci_dac ? FL_DAC : 0;
spin_lock_init(&host->lock);
INIT_WORK(&host->fsm_task, carm_fsm_task, host);
- init_MUTEX_LOCKED(&host->probe_sem);
+ init_completion(&host->probe_comp);

for (i = 0; i < ARRAY_SIZE(host->req); i++)
host->req[i].tag = i;
@@ -1710,8 +1711,8 @@ static int carm_init_one (struct pci_dev
if (rc)
goto err_out_free_irq;

- DPRINTK("waiting for probe_sem\n");
- down(&host->probe_sem);
+ DPRINTK("waiting for probe_comp\n");
+ wait_for_completion(&host->probe_comp);

printk(KERN_INFO "%s: pci %s, ports %d, io %lx, irq %u, major %d\n",
host->name, pci_name(pdev), (int) CARM_MAX_PORTS,
drivers/char/watchdog/cpu5wdt.c | 9 +++++----
1 files changed, 5 insertions(+), 4 deletions(-)

Index: linux/drivers/char/watchdog/cpu5wdt.c
===================================================================
--- linux.orig/drivers/char/watchdog/cpu5wdt.c
+++ linux/drivers/char/watchdog/cpu5wdt.c
@@ -28,6 +28,7 @@
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/timer.h>
+#include <linux/completion.h>
#include <linux/jiffies.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -57,7 +58,7 @@ static int ticks = 10000;
/* some device data */

static struct {
- struct semaphore stop;
+ struct completion stop;
volatile int running;
struct timer_list timer;
volatile int queue;
@@ -85,7 +86,7 @@ static void cpu5wdt_trigger(unsigned lon
}
else {
/* ticks doesn't matter anyway */
- up(&cpu5wdt_device.stop);
+ complete(&cpu5wdt_device.stop);
}

}
@@ -239,7 +240,7 @@ static int __devinit cpu5wdt_init(void)
if ( !val )
printk(KERN_INFO PFX "sorry, was my fault\n");

- init_MUTEX_LOCKED(&cpu5wdt_device.stop);
+ init_completion(&cpu5wdt_device.stop);
cpu5wdt_device.queue = 0;

clear_bit(0, &cpu5wdt_device.inuse);
@@ -269,7 +270,7 @@ static void __devexit cpu5wdt_exit(void)
{
if ( cpu5wdt_device.queue ) {
cpu5wdt_device.queue = 0;
- down(&cpu5wdt_device.stop);
+ wait_for_completion(&cpu5wdt_device.stop);
}

misc_deregister(&cpu5wdt_misc);
The following patch is from Montavista. I modified it slightly.
Semaphores are currently being used where it makes more sense for
completions. This patch corrects that.

-- Steve

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

Source: MontaVista Software, Inc.
Signed-off-by: Aleksey Makarov <amakarov@xxxxxxxxxxxxx>
Description:
The patch changes semaphores that are initialized as
locked to complete().

drivers/ide/ide-probe.c | 4 ++--
drivers/ide/ide.c | 8 ++++----
include/linux/ide.h | 5 +++--
3 files changed, 9 insertions(+), 8 deletions(-)

Index: linux/drivers/ide/ide-probe.c
===================================================================
--- linux.orig/drivers/ide/ide-probe.c
+++ linux/drivers/ide/ide-probe.c
@@ -655,7 +655,7 @@ static void hwif_release_dev (struct dev
{
ide_hwif_t *hwif = container_of(dev, ide_hwif_t, gendev);

- up(&hwif->gendev_rel_sem);
+ complete(&hwif->gendev_rel_comp);
}

static void hwif_register (ide_hwif_t *hwif)
@@ -1325,7 +1325,7 @@ static void drive_release_dev (struct de
drive->queue = NULL;
spin_unlock_irq(&ide_lock);

- up(&drive->gendev_rel_sem);
+ complete(&drive->gendev_rel_comp);
}

/*
Index: linux/drivers/ide/ide.c
===================================================================
--- linux.orig/drivers/ide/ide.c
+++ linux/drivers/ide/ide.c
@@ -222,7 +222,7 @@ static void init_hwif_data(ide_hwif_t *h
hwif->mwdma_mask = 0x80; /* disable all mwdma */
hwif->swdma_mask = 0x80; /* disable all swdma */

- sema_init(&hwif->gendev_rel_sem, 0);
+ init_completion(&hwif->gendev_rel_comp);

default_hwif_iops(hwif);
default_hwif_transport(hwif);
@@ -245,7 +245,7 @@ static void init_hwif_data(ide_hwif_t *h
drive->is_flash = 0;
drive->vdma = 0;
INIT_LIST_HEAD(&drive->list);
- sema_init(&drive->gendev_rel_sem, 0);
+ init_completion(&drive->gendev_rel_comp);
}
}

@@ -602,7 +602,7 @@ void ide_unregister(unsigned int index)
}
spin_unlock_irq(&ide_lock);
device_unregister(&drive->gendev);
- down(&drive->gendev_rel_sem);
+ wait_for_completion(&drive->gendev_rel_comp);
spin_lock_irq(&ide_lock);
}
hwif->present = 0;
@@ -662,7 +662,7 @@ void ide_unregister(unsigned int index)
/* More messed up locking ... */
spin_unlock_irq(&ide_lock);
device_unregister(&hwif->gendev);
- down(&hwif->gendev_rel_sem);
+ wait_for_completion(&hwif->gendev_rel_comp);

/*
* Remove us from the kernel's knowledge
Index: linux/include/linux/ide.h
===================================================================
--- linux.orig/include/linux/ide.h
+++ linux/include/linux/ide.h
@@ -18,6 +18,7 @@
#include <linux/bio.h>
#include <linux/device.h>
#include <linux/pci.h>
+#include <linux/completion.h>
#include <asm/byteorder.h>
#include <asm/system.h>
#include <asm/io.h>
@@ -759,7 +760,7 @@ typedef struct ide_drive_s {
int crc_count; /* crc counter to reduce drive speed */
struct list_head list;
struct device gendev;
- struct semaphore gendev_rel_sem; /* to deal with device release() */
+ struct completion gendev_rel_comp; /* to deal with device release() */
} ide_drive_t;

#define to_ide_device(dev)container_of(dev, ide_drive_t, gendev)
@@ -915,7 +916,7 @@ typedef struct hwif_s {
unsigned sg_mapped : 1; /* sg_table and sg_nents are ready */

struct device gendev;
- struct semaphore gendev_rel_sem; /* To deal with device release() */
+ struct completion gendev_rel_comp; /* To deal with device release() */

void *hwif_data; /* extra hwif data */