[PATCH] 10/41 sound/oss/midibuf.c - convert cli to spinlocks

From: pwaechtler@mac.com
Date: Thu Aug 29 2002 - 14:56:27 EST


--- vanilla-2.5.32/sound/oss/midibuf.c Sat Aug 10 00:04:15 2002
+++ linux-2.5-cli-oss/sound/oss/midibuf.c Wed Aug 14 22:41:29 2002
@@ -15,7 +15,7 @@
  */
 #include <linux/stddef.h>
 #include <linux/kmod.h>
-
+#include <linux/spinlock.h>
 #define MIDIBUF_C
 
 #include "sound_config.h"
@@ -55,6 +55,7 @@
 };
 
 static volatile int open_devs = 0;
+static spinlock_t lock=SPIN_LOCK_UNLOCKED;
 
 #define DATA_AVAIL(q) (q->len)
 #define SPACE_AVAIL(q) (MAX_QUEUE_SIZE - q->len)
@@ -63,20 +64,20 @@
         if (SPACE_AVAIL(q)) \
         { \
           unsigned long flags; \
- save_flags( flags);cli(); \
+ spin_lock_irqsave(&lock, flags); \
           q->queue[q->tail] = (data); \
           q->len++; q->tail = (q->tail+1) % MAX_QUEUE_SIZE; \
- restore_flags(flags); \
+ spin_unlock_irqrestore(&lock, flags); \
         }
 
 #define REMOVE_BYTE(q, data) \
         if (DATA_AVAIL(q)) \
         { \
           unsigned long flags; \
- save_flags( flags);cli(); \
+ spin_lock_irqsave(&lock, flags); \
           data = q->queue[q->head]; \
           q->len--; q->head = (q->head+1) % MAX_QUEUE_SIZE; \
- restore_flags(flags); \
+ spin_unlock_irqrestore(&lock, flags); \
         }
 
 static void drain_midi_queue(int dev)
@@ -122,8 +123,7 @@
         unsigned long flags;
         int dev;
 
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&lock, flags);
         if (open_devs)
         {
                 for (dev = 0; dev < num_midis; dev++)
@@ -135,9 +135,9 @@
                                 {
                                         int c = midi_out_buf[dev]->queue[midi_out_buf[dev]->head];
 
- restore_flags(flags); /* Give some time to others */
+ spin_unlock_irqrestore(&lock,flags);/* Give some time to others */
                                         ok = midi_devs[dev]->outputc(dev, c);
- cli();
+ spin_lock_irqsave(&lock, flags);
                                         midi_out_buf[dev]->head = (midi_out_buf[dev]->head + 1) % MAX_QUEUE_SIZE;
                                         midi_out_buf[dev]->len--;
                                 }
@@ -151,7 +151,7 @@
                  * Come back later
                  */
         }
- restore_flags(flags);
+ spin_unlock_irqrestore(&lock, flags);
 }
 
 int MIDIbuf_open(int dev, struct file *file)
@@ -217,7 +217,6 @@
 void MIDIbuf_release(int dev, struct file *file)
 {
         int mode;
- unsigned long flags;
 
         dev = dev >> 4;
         mode = translate_mode(file);
@@ -225,9 +224,6 @@
         if (dev < 0 || dev >= num_midis || midi_devs[dev] == NULL)
                 return;
 
- save_flags(flags);
- cli();
-
         /*
          * Wait until the queue is empty
          */
@@ -249,7 +245,6 @@
                                          * Ensure the output queues are empty
                                          */
         }
- restore_flags(flags);
 
         midi_devs[dev]->close(dev);
 
@@ -267,7 +262,6 @@
 
 int MIDIbuf_write(int dev, struct file *file, const char *buf, int count)
 {
- unsigned long flags;
         int c, n, i;
         unsigned char tmp_data;
 
@@ -276,9 +270,6 @@
         if (!count)
                 return 0;
 
- save_flags(flags);
- cli();
-
         c = 0;
 
         while (c < count)
@@ -308,6 +299,8 @@
                 for (i = 0; i < n; i++)
                 {
                         /* BROKE BROKE BROKE - CANT DO THIS WITH CLI !! */
+ /* yes, think the same, so I removed the cli() brackets
+ QUEUE_BYTE is protected against interrupts */
                         if (copy_from_user((char *) &tmp_data, &(buf)[c], 1)) {
                                 c = -EFAULT;
                                 goto out;
@@ -317,7 +310,6 @@
                 }
         }
 out:
- restore_flags(flags);
         return c;
 }
 
@@ -325,14 +317,10 @@
 int MIDIbuf_read(int dev, struct file *file, char *buf, int count)
 {
         int n, c = 0;
- unsigned long flags;
         unsigned char tmp_data;
 
         dev = dev >> 4;
 
- save_flags(flags);
- cli();
-
         if (!DATA_AVAIL(midi_in_buf[dev])) { /*
                                                  * No data yet, wait
                                                  */
@@ -361,6 +349,8 @@
                         REMOVE_BYTE(midi_in_buf[dev], tmp_data);
                         fixit = (char *) &tmp_data;
                         /* BROKE BROKE BROKE */
+ /* yes removed the cli() brackets again
+ should q->len,tail&head be atomic_t? */
                         if (copy_to_user(&(buf)[c], fixit, 1)) {
                                 c = -EFAULT;
                                 goto out;
@@ -369,7 +359,6 @@
                 }
         }
 out:
- restore_flags(flags);
         return c;
 }
 
@@ -440,7 +429,7 @@
 
 int MIDIbuf_avail(int dev)
 {
- if (midi_in_buf[dev])
+ if (midi_in_buf[dev])
                 return DATA_AVAIL (midi_in_buf[dev]);
         return 0;
 }

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This archive was generated by hypermail 2b29 : Sat Aug 31 2002 - 22:00:28 EST