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

diff --git a/sound/oss/midibuf.c b/sound/oss/midibuf.c
index f7a88d688fda58d66ef46246579bb128b3ef540b..f50fd0c5b663e3c8d207dbec8e19d67d0a5f4f30 100644 (file)
--- a/sound/oss/midibuf.c
+++ b/sound/oss/midibuf.c
@@ -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 struct timer_list poll_timer = {
 };
 
 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 @@ static volatile int open_devs = 0;
        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 @@ static void midi_poll(unsigned long dummy)
        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 @@ static void midi_poll(unsigned long dummy)
                                {
                                        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 @@ static void midi_poll(unsigned long dummy)
                 * Come back later
                 */
        }
-       restore_flags(flags);
+       spin_unlock_irqrestore(&lock, flags);
 }
 
 int MIDIbuf_open(int dev, struct file *file)
@@ -217,7 +217,6 @@ int MIDIbuf_open(int dev, struct file *file)
 void MIDIbuf_release(int dev, struct file *file)
 {
        int mode;
-       unsigned long flags;
 
        dev = dev >> 4;
        mode = translate_mode(file);
@@ -225,9 +224,6 @@ void MIDIbuf_release(int dev, struct file *file)
        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 @@ void MIDIbuf_release(int dev, struct file *file)
                                         * Ensure the output queues are empty
                                         */
        }
-       restore_flags(flags);
 
        midi_devs[dev]->close(dev);
 
@@ -267,7 +262,6 @@ void MIDIbuf_release(int dev, struct file *file)
 
 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 @@ int MIDIbuf_write(int dev, struct file *file, const char *buf, int count)
        if (!count)
                return 0;
 
-       save_flags(flags);
-       cli();
-
        c = 0;
 
        while (c < count)
@@ -308,6 +299,8 @@ int MIDIbuf_write(int dev, struct file *file, const char *buf, int count)
                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 @@ int MIDIbuf_write(int dev, struct file *file, const char *buf, int count)
                }
        }
 out:
-       restore_flags(flags);
        return c;
 }
 
@@ -325,14 +317,10 @@ out:
 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 @@ int MIDIbuf_read(int dev, struct file *file, char *buf, int count)
                        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 @@ int MIDIbuf_read(int dev, struct file *file, char *buf, int count)
                }
        }
 out:
-       restore_flags(flags);
        return c;
 }
 
@@ -440,7 +429,7 @@ void MIDIbuf_init(void)
 
 int MIDIbuf_avail(int dev)
 {
-        if (midi_in_buf[dev])
+       if (midi_in_buf[dev])
                return DATA_AVAIL (midi_in_buf[dev]);
        return 0;
 }