minix/lib/libblockdriver/driver_st.c

   1 /* This file contains the singlethreaded device driver interface.
   2  *
   3  * Changes:
   4  *   Aug 27, 2011   extracted from driver.c (A. Welzel)
   5  *
   6  * The entry points into this file are:
   7  *   blockdriver_task:          the main message loop of the driver
   8  *   blockdriver_terminate:     break out of the main message loop
   9  *   blockdriver_receive_mq:    message receive interface with message queueing
  10  *   blockdriver_mq_queue:      queue an incoming message for later processing
  11  */
  12
  13 #include <minix/drivers.h>
  14 #include <minix/blockdriver.h>
  15
  16 #include "const.h"
  17 #include "driver.h"
  18 #include "mq.h"
  19
  20 static int running;
  21
  22 /*===========================================================================*
  23  *                             blockdriver_receive_mq                        *
  24  *===========================================================================*/
  25 int blockdriver_receive_mq(message *m_ptr, int *status_ptr)
  26 {
  27 /* receive() interface for drivers with message queueing. */
  28
  29   /* Any queued messages? */
  30   if (mq_dequeue(SINGLE_THREAD, m_ptr, status_ptr))
  31         return OK;
  32
  33   /* Fall back to standard receive() interface otherwise. */
  34   return driver_receive(ANY, m_ptr, status_ptr);
  35 }
  36
  37 /*===========================================================================*
  38  *                              blockdriver_terminate                        *
  39  *===========================================================================*/
  40 void blockdriver_terminate(void)
  41 {
  42 /* Break out of the main driver loop after finishing the current request. */
  43
  44   running = FALSE;
  45
  46   sef_cancel();
  47 }
  48
  49 /*===========================================================================*
  50  *                              blockdriver_task                             *
  51  *===========================================================================*/
  52 void blockdriver_task(struct blockdriver *bdp)
  53 {
  54 /* Main program of any block device driver task. */
  55   int r, ipc_status;
  56   message mess;
  57
  58   running = TRUE;
  59
  60   /* Here is the main loop of the disk task.  It waits for a message, carries
  61    * it out, and sends a reply.
  62    */
  63   while (running) {
  64         if ((r = blockdriver_receive_mq(&mess, &ipc_status)) != OK) {
  65                 if (r == EINTR && !running)
  66                         break;
  67
  68                 panic("blockdriver_receive_mq failed: %d", r);
  69         }
  70
  71         blockdriver_process(bdp, &mess, ipc_status);
  72   }
  73 }
  74
  75 /*===========================================================================*
  76  *                              blockdriver_process                          *
  77  *===========================================================================*/
  78 void blockdriver_process(struct blockdriver *bdp, message *m_ptr,
  79   int ipc_status)
  80 {
  81 /* Handle the given received message. */
  82
  83   blockdriver_process_on_thread(bdp, m_ptr, ipc_status, SINGLE_THREAD);
  84 }
  85
  86 /*===========================================================================*
  87  *                              blockdriver_mq_queue                         *
  88  *===========================================================================*/
  89 int blockdriver_mq_queue(message *m, int status)
  90 {
  91 /* Queue a message for later processing. */
  92
  93   return mq_enqueue(SINGLE_THREAD, m, status);
  94 }