V4L/DVB (11819): Siano: smscore - fix get_common_buffer bug

get common buffers() should block operation until valid buffer
is avaliable.

Signed-off-by: Uri Shkolnik <uris@siano-ms.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/dvb/siano/smscoreapi.c b/drivers/media/dvb/siano/smscoreapi.c
index 040a3ff..9a5358c 100644 (file)
--- a/drivers/media/dvb/siano/smscoreapi.c
+++ b/drivers/media/dvb/siano/smscoreapi.c
@@ -30,6 +30,7 @@
 #include <linux/io.h>
 
 #include <linux/firmware.h>
+#include <linux/wait.h>
 
 #include "smscoreapi.h"
 #include "sms-cards.h"
@@ -352,6 +353,9 @@ int smscore_register_device(struct smsdevice_params_t *params,
        init_completion(&dev->resume_done);
        init_completion(&dev->ir_init_done);
 
+       /* Buffer management */
+       init_waitqueue_head(&dev->buffer_mng_waitq);
+
        /* alloc common buffer */
        dev->common_buffer_size = params->buffer_size * params->num_buffers;
        dev->common_buffer = dma_alloc_coherent(NULL, dev->common_buffer_size,
@@ -686,7 +690,9 @@ void smscore_unregister_device(struct smscore_device_t *coredev)
         * onresponse must no longer be called */
 
        while (1) {
-               while ((cb = smscore_getbuffer(coredev))) {
+               while (!list_empty(&coredev->buffers)) {
+                       cb = (struct smscore_buffer_t *) coredev->buffers.next;
+                       list_del(&cb->entry);
                        kfree(cb);
                        num_buffers++;
                }
@@ -707,8 +713,10 @@ void smscore_unregister_device(struct smscore_device_t *coredev)
 
        if (coredev->common_buffer)
                dma_free_coherent(NULL, coredev->common_buffer_size,
-                                 coredev->common_buffer,
-                                 coredev->common_buffer_phys);
+                       coredev->common_buffer, coredev->common_buffer_phys);
+
+       if (coredev->fw_buf != NULL)
+               kfree(coredev->fw_buf);
 
        list_del(&coredev->entry);
        kfree(coredev);
@@ -1071,12 +1079,24 @@ struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev)
        struct smscore_buffer_t *cb = NULL;
        unsigned long flags;
 
+       DEFINE_WAIT(wait);
+
        spin_lock_irqsave(&coredev->bufferslock, flags);
 
-       if (!list_empty(&coredev->buffers)) {
-               cb = (struct smscore_buffer_t *) coredev->buffers.next;
-               list_del(&cb->entry);
-       }
+       /* This function must return a valid buffer, since the buffer list is
+        * finite, we check that there is an available buffer, if not, we wait
+        * until such buffer become available.
+        */
+
+       prepare_to_wait(&coredev->buffer_mng_waitq, &wait, TASK_INTERRUPTIBLE);
+
+       if (list_empty(&coredev->buffers))
+               schedule();
+
+       finish_wait(&coredev->buffer_mng_waitq, &wait);
+
+       cb = (struct smscore_buffer_t *) coredev->buffers.next;
+       list_del(&cb->entry);
 
        spin_unlock_irqrestore(&coredev->bufferslock, flags);
 
@@ -1093,8 +1113,8 @@ EXPORT_SYMBOL_GPL(smscore_getbuffer);
  *
  */
 void smscore_putbuffer(struct smscore_device_t *coredev,
-                      struct smscore_buffer_t *cb)
-{
+               struct smscore_buffer_t *cb) {
+       wake_up_interruptible(&coredev->buffer_mng_waitq);
        list_add_locked(&cb->entry, &coredev->buffers, &coredev->bufferslock);
 }
 EXPORT_SYMBOL_GPL(smscore_putbuffer);