V4L/DVB (12199): remove redundant tests on unsigned
[safe/jmp/linux-2.6] / drivers / media / video / cx18 / cx18-queue.c
index 2c58b0c..fa1ed78 100644 (file)
@@ -23,8 +23,8 @@
  */
 
 #include "cx18-driver.h"
-#include "cx18-streams.h"
 #include "cx18-queue.h"
+#include "cx18-streams.h"
 #include "cx18-scb.h"
 
 void cx18_buf_swap(struct cx18_buffer *buf)
@@ -53,13 +53,13 @@ struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
                buf->skipped = 0;
        }
 
-       mutex_lock(&s->qlock);
-
        /* q_busy is restricted to a max buffer count imposed by firmware */
        if (q == &s->q_busy &&
            atomic_read(&q->buffers) >= CX18_MAX_FW_MDLS_PER_STREAM)
                q = &s->q_free;
 
+       spin_lock(&q->lock);
+
        if (to_front)
                list_add(&buf->list, &q->list); /* LIFO */
        else
@@ -67,7 +67,7 @@ struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
        q->bytesused += buf->bytesused - buf->readpos;
        atomic_inc(&q->buffers);
 
-       mutex_unlock(&s->qlock);
+       spin_unlock(&q->lock);
        return q;
 }
 
@@ -75,15 +75,15 @@ struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
 {
        struct cx18_buffer *buf = NULL;
 
-       mutex_lock(&s->qlock);
+       spin_lock(&q->lock);
        if (!list_empty(&q->list)) {
-               buf = list_entry(q->list.next, struct cx18_buffer, list);
-               list_del_init(q->list.next);
+               buf = list_first_entry(&q->list, struct cx18_buffer, list);
+               list_del_init(&buf->list);
                q->bytesused -= buf->bytesused - buf->readpos;
                buf->skipped = 0;
                atomic_dec(&q->buffers);
        }
-       mutex_unlock(&s->qlock);
+       spin_unlock(&q->lock);
        return buf;
 }
 
@@ -92,13 +92,25 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
 {
        struct cx18 *cx = s->cx;
        struct cx18_buffer *buf;
+       struct cx18_buffer *tmp;
        struct cx18_buffer *ret = NULL;
-       struct list_head *p, *t;
-
-       mutex_lock(&s->qlock);
-       list_for_each_safe(p, t, &s->q_busy.list) {
-               buf = list_entry(p, struct cx18_buffer, list);
-
+       LIST_HEAD(sweep_up);
+
+       /*
+        * We don't have to acquire multiple q locks here, because we are
+        * serialized by the single threaded work handler.
+        * Buffers from the firmware will thus remain in order as
+        * they are moved from q_busy to q_full or to the dvb ring buffer.
+        */
+       spin_lock(&s->q_busy.lock);
+       list_for_each_entry_safe(buf, tmp, &s->q_busy.list, list) {
+               /*
+                * We should find what the firmware told us is done,
+                * right at the front of the queue.  If we don't, we likely have
+                * missed a buffer done message from the firmware.
+                * Once we skip a buffer repeatedly, relative to the size of
+                * q_busy, we have high confidence we've missed it.
+                */
                if (buf->id != id) {
                        buf->skipped++;
                        if (buf->skipped >= atomic_read(&s->q_busy.buffers)-1) {
@@ -107,38 +119,41 @@ struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
                                          "times - it must have dropped out of "
                                          "rotation\n", s->name, buf->id,
                                          buf->skipped);
-                               /* move it to q_free */
-                               list_move_tail(&buf->list, &s->q_free.list);
-                               buf->bytesused = buf->readpos = buf->b_flags =
-                                       buf->skipped = 0;
+                               /* Sweep it up to put it back into rotation */
+                               list_move_tail(&buf->list, &sweep_up);
                                atomic_dec(&s->q_busy.buffers);
-                               atomic_inc(&s->q_free.buffers);
                        }
                        continue;
                }
-
-               buf->bytesused = bytesused;
-               /* Sync the buffer before we release the qlock */
-               cx18_buf_sync_for_cpu(s, buf);
-               if (s->type == CX18_ENC_STREAM_TYPE_TS) {
-                       /*
-                        * TS doesn't use q_full.  As we pull the buffer off of
-                        * the queue here, the caller will have to put it back.
-                        */
-                       list_del_init(&buf->list);
-               } else {
-                       /* Move buffer from q_busy to q_full */
-                       list_move_tail(&buf->list, &s->q_full.list);
-                       set_bit(CX18_F_B_NEED_BUF_SWAP, &buf->b_flags);
-                       s->q_full.bytesused += buf->bytesused;
-                       atomic_inc(&s->q_full.buffers);
-               }
+               /*
+                * We pull the desired buffer off of the queue here.  Something
+                * will have to put it back on a queue later.
+                */
+               list_del_init(&buf->list);
                atomic_dec(&s->q_busy.buffers);
-
                ret = buf;
                break;
        }
-       mutex_unlock(&s->qlock);
+       spin_unlock(&s->q_busy.lock);
+
+       /*
+        * We found the buffer for which we were looking.  Get it ready for
+        * the caller to put on q_full or in the dvb ring buffer.
+        */
+       if (ret != NULL) {
+               ret->bytesused = bytesused;
+               ret->skipped = 0;
+               /* readpos and b_flags were 0'ed when the buf went on q_busy */
+               cx18_buf_sync_for_cpu(s, ret);
+               if (s->type != CX18_ENC_STREAM_TYPE_TS)
+                       set_bit(CX18_F_B_NEED_BUF_SWAP, &ret->b_flags);
+       }
+
+       /* Put any buffers the firmware is ignoring back into normal rotation */
+       list_for_each_entry_safe(buf, tmp, &sweep_up, list) {
+               list_del_init(&buf->list);
+               cx18_enqueue(s, buf, &s->q_free);
+       }
        return ret;
 }
 
@@ -150,15 +165,15 @@ static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
        if (q == &s->q_free)
                return;
 
-       mutex_lock(&s->qlock);
+       spin_lock(&q->lock);
        while (!list_empty(&q->list)) {
-               buf = list_entry(q->list.next, struct cx18_buffer, list);
-               list_move_tail(q->list.next, &s->q_free.list);
+               buf = list_first_entry(&q->list, struct cx18_buffer, list);
+               list_move_tail(&buf->list, &s->q_free.list);
                buf->bytesused = buf->readpos = buf->b_flags = buf->skipped = 0;
                atomic_inc(&s->q_free.buffers);
        }
        cx18_queue_init(q);
-       mutex_unlock(&s->qlock);
+       spin_unlock(&q->lock);
 }
 
 void cx18_flush_queues(struct cx18_stream *s)
@@ -206,7 +221,7 @@ int cx18_stream_alloc(struct cx18_stream *s)
                }
                buf->id = cx->buffer_id++;
                INIT_LIST_HEAD(&buf->list);
-               buf->dma_handle = pci_map_single(s->cx->dev,
+               buf->dma_handle = pci_map_single(s->cx->pci_dev,
                                buf->buf, s->buf_size, s->dma);
                cx18_buf_sync_for_cpu(s, buf);
                cx18_enqueue(s, buf, &s->q_free);
@@ -229,7 +244,7 @@ void cx18_stream_free(struct cx18_stream *s)
 
        /* empty q_free */
        while ((buf = cx18_dequeue(s, &s->q_free))) {
-               pci_unmap_single(s->cx->dev, buf->dma_handle,
+               pci_unmap_single(s->cx->pci_dev, buf->dma_handle,
                                s->buf_size, s->dma);
                kfree(buf->buf);
                kfree(buf);