caif-shm: Bugfixes for caif_shmcore.c

Various bugfixes for caif_shmcore.c:
- fix deadlocks due to improper usage of spin-lock
- add missing spin-lock init
- don't call dev_kfree_skb() with irqs disabled,
  use dev_kfree_skb_irq() instead.
- fix potential skb null pointer de-reference.

Squashed original patches from:
Rabin Vincent <rabin.vincent@stericsson.com>
Durga Prasada Rao BATHINA <durgaprasadarao.b@stericcson.com>
Arun Murthy <arun.murthy@stericsson.com>
Bibek Basu <bibek.basu@stericsson.com>

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/net/caif/caif_shmcore.c b/drivers/net/caif/caif_shmcore.c
index d4b26fb24ed9..fd59e37e28a1 100644
--- a/drivers/net/caif/caif_shmcore.c
+++ b/drivers/net/caif/caif_shmcore.c
@@ -238,11 +238,11 @@ int caif_shmdrv_rx_cb(u32 mbx_msg, void *priv)
                 if ((avail_emptybuff > HIGH_WATERMARK) &&
                                         (!pshm_drv->tx_empty_available)) {
                         pshm_drv->tx_empty_available = 1;
+                        spin_unlock_irqrestore(&pshm_drv->lock, flags);
                         pshm_drv->cfdev.flowctrl
                                         (pshm_drv->pshm_dev->pshm_netdev,
                                                                 CAIF_FLOW_ON);
 
-                        spin_unlock_irqrestore(&pshm_drv->lock, flags);
 
                         /* Schedule the work queue. if required */
                         if (!work_pending(&pshm_drv->shm_tx_work))
@@ -285,6 +285,7 @@ static void shm_rx_work_func(struct work_struct *rx_work)
                         list_entry(pshm_drv->rx_full_list.next, struct buf_list,
                                         list);
                 list_del_init(&pbuf->list);
+                spin_unlock_irqrestore(&pshm_drv->lock, flags);
 
                 /* Retrieve pointer to start of the packet descriptor area. */
                 pck_desc = (struct shm_pck_desc *) pbuf->desc_vptr;
@@ -360,6 +361,7 @@ static void shm_rx_work_func(struct work_struct *rx_work)
                         pck_desc++;
                 }
 
+                spin_lock_irqsave(&pshm_drv->lock, flags);
                 list_add_tail(&pbuf->list, &pshm_drv->rx_pend_list);
 
                 spin_unlock_irqrestore(&pshm_drv->lock, flags);
@@ -412,7 +414,6 @@ static void shm_tx_work_func(struct work_struct *tx_work)
 
                 if (skb == NULL)
                         goto send_msg;
-
                 /* Check the available no. of buffers in the empty list */
                 list_for_each(pos, &pshm_drv->tx_empty_list)
                         avail_emptybuff++;
@@ -421,9 +422,11 @@ static void shm_tx_work_func(struct work_struct *tx_work)
                                         pshm_drv->tx_empty_available) {
                         /* Update blocking condition. */
                         pshm_drv->tx_empty_available = 0;
+                        spin_unlock_irqrestore(&pshm_drv->lock, flags);
                         pshm_drv->cfdev.flowctrl
                                         (pshm_drv->pshm_dev->pshm_netdev,
                                         CAIF_FLOW_OFF);
+                        spin_lock_irqsave(&pshm_drv->lock, flags);
                 }
                 /*
                  * We simply return back to the caller if we do not have space
@@ -469,6 +472,8 @@ static void shm_tx_work_func(struct work_struct *tx_work)
                         }
 
                         skb = skb_dequeue(&pshm_drv->sk_qhead);
+                        if (skb == NULL)
+                                break;
                         /* Copy in CAIF frame. */
                         skb_copy_bits(skb, 0, pbuf->desc_vptr +
                                         pbuf->frm_ofs + SHM_HDR_LEN +
@@ -477,7 +482,7 @@ static void shm_tx_work_func(struct work_struct *tx_work)
                         pshm_drv->pshm_dev->pshm_netdev->stats.tx_packets++;
                         pshm_drv->pshm_dev->pshm_netdev->stats.tx_bytes +=
                                                                         frmlen;
-                        dev_kfree_skb(skb);
+                        dev_kfree_skb_irq(skb);
 
                         /* Fill in the shared memory packet descriptor area. */
                         pck_desc = (struct shm_pck_desc *) (pbuf->desc_vptr);
@@ -512,16 +517,11 @@ send_msg:
 static int shm_netdev_tx(struct sk_buff *skb, struct net_device *shm_netdev)
 {
         struct shmdrv_layer *pshm_drv;
-        unsigned long flags = 0;
 
         pshm_drv = netdev_priv(shm_netdev);
 
-        spin_lock_irqsave(&pshm_drv->lock, flags);
-
         skb_queue_tail(&pshm_drv->sk_qhead, skb);
 
-        spin_unlock_irqrestore(&pshm_drv->lock, flags);
-
         /* Schedule Tx work queue. for deferred processing of skbs*/
         if (!work_pending(&pshm_drv->shm_tx_work))
                 queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);
@@ -606,6 +606,7 @@ int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
                 pshm_drv->shm_rx_addr = pshm_dev->shm_base_addr +
                                                 (NR_TX_BUF * TX_BUF_SZ);
 
+        spin_lock_init(&pshm_drv->lock);
         INIT_LIST_HEAD(&pshm_drv->tx_empty_list);
         INIT_LIST_HEAD(&pshm_drv->tx_pend_list);
         INIT_LIST_HEAD(&pshm_drv->tx_full_list);
@@ -640,7 +641,7 @@ int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
                 tx_buf->frm_ofs = SHM_CAIF_FRM_OFS;
 
                 if (pshm_dev->shm_loopback)
-                        tx_buf->desc_vptr = (char *)tx_buf->phy_addr;
+                        tx_buf->desc_vptr = (unsigned char *)tx_buf->phy_addr;
                 else
                         tx_buf->desc_vptr =
                                         ioremap(tx_buf->phy_addr, TX_BUF_SZ);
@@ -664,7 +665,7 @@ int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
                 rx_buf->len = RX_BUF_SZ;
 
                 if (pshm_dev->shm_loopback)
-                        rx_buf->desc_vptr = (char *)rx_buf->phy_addr;
+                        rx_buf->desc_vptr = (unsigned char *)rx_buf->phy_addr;
                 else
                         rx_buf->desc_vptr =
                                         ioremap(rx_buf->phy_addr, RX_BUF_SZ);