arm-omap: don't abuse rq->data

omap mailbox uses rq->data as the second opaque pointer to carry
mbox_msg_t and rq->special message argument which is needed only for
tx.  Add and use omap_msg_tx_data struct for tx and use rq->special
for mbox_msg_t for rx such that only rq->special is used as opaque
pointer.

[ Impact: cleanup rq->data usage, extra kmalloc in msg_send ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>

1 files changed, 31 insertions, 12 deletions

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index cf81bad8aec2..538ba7541d3f 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -147,24 +147,40 @@ static int __mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void *arg)
         return ret;
 }
 
+struct omap_msg_tx_data {
+        mbox_msg_t      msg;
+        void            *arg;
+};
+
+static void omap_msg_tx_end_io(struct request *rq, int error)
+{
+        kfree(rq->special);
+        __blk_put_request(rq->q, rq);
+}
+
 int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg, void* arg)
 {
+        struct omap_msg_tx_data *tx_data;
         struct request *rq;
         struct request_queue *q = mbox->txq->queue;
-        int ret = 0;
+
+        tx_data = kmalloc(sizeof(*tx_data), GFP_ATOMIC);
+        if (unlikely(!tx_data))
+                return -ENOMEM;
 
         rq = blk_get_request(q, WRITE, GFP_ATOMIC);
         if (unlikely(!rq)) {
-                ret = -ENOMEM;
-                goto fail;
+                kfree(tx_data);
+                return -ENOMEM;
         }
 
-        rq->data = (void *)msg;
-        blk_insert_request(q, rq, 0, arg);
+        tx_data->msg = msg;
+        tx_data->arg = arg;
+        rq->end_io = omap_msg_tx_end_io;
+        blk_insert_request(q, rq, 0, tx_data);
 
         schedule_work(&mbox->txq->work);
- fail:
-        return ret;
+        return 0;
 }
 EXPORT_SYMBOL(omap_mbox_msg_send);
 
@@ -178,6 +194,8 @@ static void mbox_tx_work(struct work_struct *work)
         struct request_queue *q = mbox->txq->queue;
 
         while (1) {
+                struct omap_msg_tx_data *tx_data;
+
                 spin_lock(q->queue_lock);
                 rq = elv_next_request(q);
                 spin_unlock(q->queue_lock);
@@ -185,7 +203,9 @@ static void mbox_tx_work(struct work_struct *work)
                 if (!rq)
                         break;
 
-                ret = __mbox_msg_send(mbox, (mbox_msg_t) rq->data, rq->special);
+                tx_data = rq->special;
+
+                ret = __mbox_msg_send(mbox, tx_data->msg, tx_data->arg);
                 if (ret) {
                         enable_mbox_irq(mbox, IRQ_TX);
                         return;
@@ -222,7 +242,7 @@ static void mbox_rx_work(struct work_struct *work)
                 if (!rq)
                         break;
 
-                msg = (mbox_msg_t) rq->data;
+                msg = (mbox_msg_t)rq->special;
                 blk_end_request_all(rq, 0);
                 mbox->rxq->callback((void *)msg);
         }
@@ -260,7 +280,6 @@ static void __mbox_rx_interrupt(struct omap_mbox *mbox)
                         goto nomem;
 
                 msg = mbox_fifo_read(mbox);
-                rq->data = (void *)msg;
 
                 if (unlikely(mbox_seq_test(mbox, msg))) {
                         pr_info("mbox: Illegal seq bit!(%08x)\n", msg);
@@ -268,7 +287,7 @@ static void __mbox_rx_interrupt(struct omap_mbox *mbox)
                                 mbox->err_notify();
                 }
 
-                blk_insert_request(q, rq, 0, NULL);
+                blk_insert_request(q, rq, 0, (void *)msg);
                 if (mbox->ops->type == OMAP_MBOX_TYPE1)
                         break;
         }
@@ -331,7 +350,7 @@ omap_mbox_read(struct device *dev, struct device_attribute *attr, char *buf)
                 if (!rq)
                         break;
 
-                *p = (mbox_msg_t) rq->data;
+                *p = (mbox_msg_t)rq->special;
 
                 blk_end_request_all(rq, 0);