staging: most: add fair buffer distribution

This patch ensures a fair distribution of buffers, when two AIMs share a
single channel. The AIMs then won't be able to use more than half of all
pre-allocated buffers of the linked channel. However, in case the channel
is not shared, the AIM can exclusively use all available buffers.

Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/most/aim-cdev/cdev.c b/drivers/staging/most/aim-cdev/cdev.c
index a8a7689231ac3a273603e1525fedf9f4900f787f..23c3f6e7340c346107d2130ca9bf14065e9420e2 100644 (file)
--- a/drivers/staging/most/aim-cdev/cdev.c
+++ b/drivers/staging/most/aim-cdev/cdev.c
@@ -165,7 +165,7 @@ static ssize_t aim_write(struct file *filp, const char __user *buf,
        }
        mutex_unlock(&channel->io_mutex);
 
-       mbo = most_get_mbo(channel->iface, channel->channel_id);
+       mbo = most_get_mbo(channel->iface, channel->channel_id, &cdev_aim);
 
        if (!mbo) {
                if ((filp->f_flags & O_NONBLOCK))
@@ -173,7 +173,8 @@ static ssize_t aim_write(struct file *filp, const char __user *buf,
                if (wait_event_interruptible(
                            channel->wq,
                            (mbo = most_get_mbo(channel->iface,
-                                               channel->channel_id)) ||
+                                               channel->channel_id,
+                                               &cdev_aim)) ||
                            (!channel->dev)))
                        return -ERESTARTSYS;
        }

diff --git a/drivers/staging/most/aim-network/networking.c b/drivers/staging/most/aim-network/networking.c
index c13bd89226d3dd0ad358c8997c71b6e57fdbf39b..f0d9a439544e98e93cf85dcad89e5d4dd514a102 100644 (file)
--- a/drivers/staging/most/aim-network/networking.c
+++ b/drivers/staging/most/aim-network/networking.c
@@ -245,7 +245,7 @@ static netdev_tx_t most_nd_start_xmit(struct sk_buff *skb,
 
        BUG_ON(nd->dev != dev);
 
-       mbo = most_get_mbo(nd->iface, nd->tx.ch_id);
+       mbo = most_get_mbo(nd->iface, nd->tx.ch_id, &aim);
 
        if (!mbo) {
                netif_stop_queue(dev);

diff --git a/drivers/staging/most/aim-sound/sound.c b/drivers/staging/most/aim-sound/sound.c
index 2d4732c10df4d113ff12b4845a90b099601d8b1f..0d7425b19f1ea978c67edb07f797831b5d9fed6e 100644 (file)
--- a/drivers/staging/most/aim-sound/sound.c
+++ b/drivers/staging/most/aim-sound/sound.c
@@ -251,7 +251,8 @@ static int playback_thread(void *data)
                wait_event_interruptible(
                        channel->playback_waitq,
                        kthread_should_stop() ||
-                       (mbo = most_get_mbo(channel->iface, channel->id)));
+                       (mbo = most_get_mbo(channel->iface, channel->id,
+                                           &audio_aim)));
 
                if (!mbo)
                        continue;

diff --git a/drivers/staging/most/hdm-dim2/dim2_hdm.c b/drivers/staging/most/hdm-dim2/dim2_hdm.c
index 4481a0be15b99d0d7cb7594d9fb4e9e33c7e116f..1bb70b73815504c6ee366aad8cdec13a25b7b30c 100644 (file)
--- a/drivers/staging/most/hdm-dim2/dim2_hdm.c
+++ b/drivers/staging/most/hdm-dim2/dim2_hdm.c
@@ -669,7 +669,7 @@ static void request_netinfo(struct most_interface *most_iface, int ch_idx)
                return;
        }
 
-       mbo = most_get_mbo(&dev->most_iface, dev->atx_idx);
+       mbo = most_get_mbo(&dev->most_iface, dev->atx_idx, NULL);
        if (!mbo)
                return;
 

diff --git a/drivers/staging/most/mostcore/core.c b/drivers/staging/most/mostcore/core.c
index 0053b8cc5363a9df01207160cd73dbd01886aed6..4dfa0015f4b0d25d082a04da4532693df9775586 100644 (file)
--- a/drivers/staging/most/mostcore/core.c
+++ b/drivers/staging/most/mostcore/core.c
@@ -36,6 +36,7 @@ static struct class *most_class;
 static struct device *class_glue_dir;
 static struct ida mdev_id;
 static int modref;
+static int dummy_num_buffers;
 
 struct most_c_obj {
        struct kobject kobj;
@@ -59,6 +60,8 @@ struct most_c_obj {
        struct most_aim *second_aim;
        int first_aim_refs;
        int second_aim_refs;
+       int first_num_buffers;
+       int second_num_buffers;
        struct list_head trash_fifo;
        struct task_struct *hdm_enqueue_task;
        struct mutex stop_task_mutex;
@@ -1233,6 +1236,7 @@ static void arm_mbo(struct mbo *mbo)
        }
 
        spin_lock_irqsave(&c->fifo_lock, flags);
+       ++*mbo->num_buffers_ptr;
        list_add_tail(&mbo->list, &c->fifo);
        spin_unlock_irqrestore(&c->fifo_lock, flags);
 
@@ -1286,6 +1290,7 @@ static int arm_mbo_chain(struct most_c_obj *c, int dir,
                        goto _error1;
                }
                mbo->complete = compl;
+               mbo->num_buffers_ptr = &dummy_num_buffers;
                if (dir == MOST_CH_RX) {
                        nq_hdm_mbo(mbo);
                        atomic_inc(&c->mbo_nq_level);
@@ -1384,22 +1389,40 @@ most_c_obj *get_channel_by_iface(struct most_interface *iface, int id)
  * This attempts to get a free buffer out of the channel fifo.
  * Returns a pointer to MBO on success or NULL otherwise.
  */
-struct mbo *most_get_mbo(struct most_interface *iface, int id)
+struct mbo *most_get_mbo(struct most_interface *iface, int id,
+                        struct most_aim *aim)
 {
        struct mbo *mbo;
        struct most_c_obj *c;
        unsigned long flags;
+       int *num_buffers_ptr;
 
        c = get_channel_by_iface(iface, id);
        if (unlikely(!c))
                return NULL;
+
+       if (c->first_aim_refs && c->second_aim_refs &&
+           ((aim == c->first_aim && c->first_num_buffers <= 0) ||
+            (aim == c->second_aim && c->second_num_buffers <= 0)))
+               return NULL;
+
+       if (aim == c->first_aim)
+               num_buffers_ptr = &c->first_num_buffers;
+       else if (aim == c->second_aim)
+               num_buffers_ptr = &c->second_num_buffers;
+       else
+               num_buffers_ptr = &dummy_num_buffers;
+
        spin_lock_irqsave(&c->fifo_lock, flags);
        if (list_empty(&c->fifo)) {
                spin_unlock_irqrestore(&c->fifo_lock, flags);
                return NULL;
        }
        mbo = list_pop_mbo(&c->fifo);
+       --*num_buffers_ptr;
        spin_unlock_irqrestore(&c->fifo_lock, flags);
+
+       mbo->num_buffers_ptr = num_buffers_ptr;
        mbo->buffer_length = c->cfg.buffer_size;
        return mbo;
 }
@@ -1530,6 +1553,8 @@ int most_start_channel(struct most_interface *iface, int id,
                goto error;
 
        c->is_starving = 0;
+       c->first_num_buffers = c->cfg.num_buffers / 2;
+       c->second_num_buffers = c->cfg.num_buffers - c->first_num_buffers;
        atomic_set(&c->mbo_ref, num_buffer);
 
 out:

diff --git a/drivers/staging/most/mostcore/mostcore.h b/drivers/staging/most/mostcore/mostcore.h
index e23ad7c332496d2819c9af3013bd6f0092f59e39..3c6fb19aaa3bf44a874657b61f431f03776ba529 100644 (file)
--- a/drivers/staging/most/mostcore/mostcore.h
+++ b/drivers/staging/most/mostcore/mostcore.h
@@ -190,6 +190,7 @@ struct mbo {
        void *priv;
        struct list_head list;
        struct most_interface *ifp;
+       int *num_buffers_ptr;
        u16 hdm_channel_id;
        void *virt_address;
        dma_addr_t bus_address;
@@ -307,7 +308,8 @@ void most_stop_enqueue(struct most_interface *iface, int channel_idx);
 void most_resume_enqueue(struct most_interface *iface, int channel_idx);
 int most_register_aim(struct most_aim *aim);
 int most_deregister_aim(struct most_aim *aim);
-struct mbo *most_get_mbo(struct most_interface *iface, int channel_idx);
+struct mbo *most_get_mbo(struct most_interface *iface, int channel_idx,
+                        struct most_aim *);
 void most_put_mbo(struct mbo *mbo);
 int most_start_channel(struct most_interface *iface, int channel_idx,
                       struct most_aim *);