drivers/can/can.c: Fix errors with pointers when using internal OS interface (#118)

Author: Gregory Nutt <gnutt@nuttx.org>

    Run all .c and .h files in last PR through tools/nxstyle and correct all coding standard complaints.

Author: Oleg <ev.mipt@gmail.com>

    * Fix CAN driver to work with internal OS interfaces.  Store internal file pointer in f_priv and use it then to distinct readers (See issue #111)
    * Store reader pointer in f_priv instead of filep
    * Don't need in filep in can_reader_s

drivers/can/can.c

@@ -390,7 +390,7 @@ static FAR struct can_reader_s *init_can_reader(FAR struct file *filep)
   reader->fifo.rx_tail  = 0;
 
   nxsem_init(&reader->fifo.rx_sem, 0, 1);
-  reader->filep = filep;
+  filep->f_priv = reader;
 
   return reader;
 }
@@ -509,7 +509,8 @@ static int can_close(FAR struct file *filep)
 
   list_for_every_safe(&dev->cd_readers, node, tmp)
     {
-      if (((FAR struct can_reader_s *)node)->filep == filep)
+      if (((FAR struct can_reader_s *)node) ==
+          ((FAR struct can_reader_s *)filep->f_priv))
         {
           list_delete(node);
           kmm_free(node);
@@ -517,6 +518,8 @@ static int can_close(FAR struct file *filep)
         }
     }
 
+  filep->f_priv = NULL;
+
   /* Decrement the references to the driver.  If the reference count will
    * decrement to 0, then uninitialize the driver.
    */
@@ -574,7 +577,6 @@ static ssize_t can_read(FAR struct file *filep, FAR char *buffer,
   FAR struct inode         *inode = filep->f_inode;
   FAR struct can_dev_s     *dev = inode->i_private;
   FAR struct can_reader_s  *reader = NULL;
-  FAR struct list_node     *node;
   FAR struct can_rxfifo_s  *fifo;
   size_t                    nread;
   irqstate_t                flags;
@@ -630,16 +632,8 @@ static ssize_t can_read(FAR struct file *filep, FAR char *buffer,
         }
 #endif /* CONFIG_CAN_ERRORS */
 
-      list_for_every(&dev->cd_readers, node)
+      DEBUGASSERT(filep->f_priv != NULL);
-        {
+      reader = (FAR struct can_reader_s *)filep->f_priv;
-          if (((FAR struct can_reader_s *) node)->filep == filep)
-            {
-              reader = (FAR struct can_reader_s *)node;
-              break;
-            }
-        }
-
-      DEBUGASSERT(reader != NULL);
 
       fifo = &reader->fifo;
 
@@ -1027,7 +1021,6 @@ static int can_poll(FAR struct file *filep, FAR struct pollfd *fds,
   FAR struct inode *inode = (FAR struct inode *)filep->f_inode;
   FAR struct can_dev_s *dev = (FAR struct can_dev_s *)inode->i_private;
   FAR struct can_reader_s *reader = NULL;
-  FAR struct list_node *node;
   pollevent_t eventset;
   int ndx;
   int ret;
@@ -1042,16 +1035,8 @@ static int can_poll(FAR struct file *filep, FAR struct pollfd *fds,
     }
 #endif
 
-  list_for_every(&dev->cd_readers, node)
+  DEBUGASSERT(filep->f_priv != NULL);
-    {
+  reader = (FAR struct can_reader_s *)filep->f_priv;
-      if (((FAR struct can_reader_s *)node)->filep == filep)
-        {
-          reader = (FAR struct can_reader_s *)node;
-          break;
-        }
-    }
-
-  DEBUGASSERT(reader != NULL);
 
   /* Get exclusive access to the poll structures */
 

include/nuttx/can/can.h

@@ -561,7 +561,6 @@ struct can_reader_s
 {
   struct list_node     list;
   sem_t                read_sem;
-  FAR struct file     *filep;
   struct can_rxfifo_s  fifo;             /* Describes receive FIFO */
 };
 
@@ -590,6 +589,7 @@ struct can_dev_s
 };
 
 /* Structures used with ioctl calls */
+
 /* CANIOC_RTR: */
 
 struct canioc_rtr_s
@@ -598,8 +598,9 @@ struct canioc_rtr_s
   FAR struct can_msg_s *ci_msg;          /* The location to return the RTR response */
 };
 
-/* CANIOC_GET_BITTIMING/CANIOC_SET_BITTIMING: */
+/* CANIOC_GET_BITTIMING/CANIOC_SET_BITTIMING:
-/* Bit time = Tquanta * (Sync_Seg + Prop_Seq + Phase_Seg1 + Phase_Seg2)
+ *
+ * Bit time = Tquanta * (Sync_Seg + Prop_Seq + Phase_Seg1 + Phase_Seg2)
  *          = Tquanta * (TSEG1 + TSEG2 + 1)
  * Where
  *   TSEG1 = Prop_Seq + Phase_Seg1
@@ -614,8 +615,9 @@ struct canioc_bittiming_s
   uint8_t               bt_sjw;          /* Synchronization Jump Width in time quanta */
 };
 
-/* CANIOC_GET_CONNMODES/CANIOC_SET_CONNMODES: */
+/* CANIOC_GET_CONNMODES/CANIOC_SET_CONNMODES:
-/* A CAN device may support loopback and silent mode. Both modes may not be
+ *
+ * A CAN device may support loopback and silent mode. Both modes may not be
  * settable independently.
  */
 
@@ -654,11 +656,7 @@ struct canioc_stdfilter_s
 };
 
 /************************************************************************************
- * Public Data
+ * Public Function Prototypes
- ************************************************************************************/
-
-/************************************************************************************
- * Public Functions
  ************************************************************************************/
 
 #undef EXTERN