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_handle_msg:    handle a single received message
  10  *   blockdriver_receive_mq:    message receive interface with message queueing
  11  *   blockdriver_mq_queue:      queue an incoming message for later processing
  12  */
  13
  14 #include <minix/drivers.h>
  15 #include <minix/blockdriver.h>
  16
  17 #include "const.h"
  18 #include "driver.h"
  19 #include "mq.h"
  20
  21 static int running;
  22
  23 /*===========================================================================*
  24  *                             blockdriver_receive_mq                        *
  25  *===========================================================================*/
  26 int blockdriver_receive_mq(message *m_ptr, int *status_ptr)
  27 {
  28 /* receive() interface for drivers with message queueing. */
  29
  30   /* Any queued messages? */
  31   if (mq_dequeue(SINGLE_THREAD, m_ptr, status_ptr))
  32         return OK;
  33
  34   /* Fall back to standard receive() interface otherwise. */
  35   return driver_receive(ANY, m_ptr, status_ptr);
  36 }
  37
  38 /*===========================================================================*
  39  *                              blockdriver_terminate                        *
  40  *===========================================================================*/
  41 void blockdriver_terminate(void)
  42 {
  43 /* Break out of the main driver loop after finishing the current request. */
  44
  45   running = FALSE;
  46 }
  47
  48 /*===========================================================================*
  49  *                              blockdriver_task                             *
  50  *===========================================================================*/
  51 void blockdriver_task(struct blockdriver *bdp)
  52 {
  53 /* Main program of any block device driver task. */
  54   int r, ipc_status;
  55   message mess;
  56
  57   running = TRUE;
  58
  59   /* Here is the main loop of the disk task.  It waits for a message, carries
  60    * it out, and sends a reply.
  61    */
  62   while (running) {
  63         if ((r = blockdriver_receive_mq(&mess, &ipc_status)) != OK)
  64                 panic("blockdriver_receive_mq failed: %d", r);
  65
  66         blockdriver_process(bdp, &mess, ipc_status);
  67   }
  68 }
  69
  70 /*===========================================================================*
  71  *                              blockdriver_process                          *
  72  *===========================================================================*/
  73 void blockdriver_process(struct blockdriver *bdp, message *m_ptr,
  74   int ipc_status)
  75 {
  76 /* Handle the given received message. */
  77   int r;
  78
  79   /* Process the notification or request. */
  80   if (is_ipc_notify(ipc_status)) {
  81         blockdriver_handle_notify(bdp, m_ptr);
  82
  83         /* Do not reply to notifications. */
  84   } else {
  85         r = blockdriver_handle_request(bdp, m_ptr, SINGLE_THREAD);
  86
  87         blockdriver_reply(m_ptr, ipc_status, r);
  88   }
  89 }
  90
  91 /*===========================================================================*
  92  *                              blockdriver_mq_queue                         *
  93  *===========================================================================*/
  94 int blockdriver_mq_queue(message *m, int status)
  95 {
  96 /* Queue a message for later processing. */
  97
  98   return mq_enqueue(SINGLE_THREAD, m, status);
  99 }