b4d909d415
This patch separates the character and block driver communication protocols. The old character protocol remains the same, but a new block protocol is introduced. The libdriver library is replaced by two new libraries: libchardriver and libblockdriver. Their exposed API, and drivers that use them, have been updated accordingly. Together, libbdev and libblockdriver now completely abstract away the message format used by the block protocol. As the memory driver is both a character and a block device driver, it now implements its own message loop. The most important semantic change made to the block protocol is that it is no longer possible to return both partial results and an error for a single transfer. This simplifies the interaction between the caller and the driver, as the I/O vector no longer needs to be copied back. Also, drivers are now no longer supposed to decide based on the layout of the I/O vector when a transfer should be cut short. Put simply, transfers are now supposed to either succeed completely, or result in an error. After this patch, the state of the various pieces is as follows: - block protocol: stable - libbdev API: stable for synchronous communication - libblockdriver API: needs slight revision (the drvlib/partition API in particular; the threading API will also change shortly) - character protocol: needs cleanup - libchardriver API: needs cleanup accordingly - driver restarts: largely unsupported until endpoint changes are reintroduced As a side effect, this patch eliminates several bugs, hacks, and gcc -Wall and -W warnings all over the place. It probably introduces a few new ones, too. Update warning: this patch changes the protocol between MFS and disk drivers, so in order to use old/new images, the MFS from the ramdisk must be used to mount all file systems.
99 lines
3 KiB
C
99 lines
3 KiB
C
/* This file contains the singlethreaded device driver interface.
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*
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* Changes:
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* Aug 27, 2011 extracted from driver.c (A. Welzel)
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*
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* The entry points into this file are:
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* blockdriver_task: the main message loop of the driver
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* blockdriver_terminate: break out of the main message loop
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* blockdriver_handle_msg: handle a single received message
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* blockdriver_receive_mq: message receive interface with message queueing
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* blockdriver_mq_queue: queue an incoming message for later processing
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*/
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#include <minix/drivers.h>
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#include <minix/blockdriver.h>
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#include "driver.h"
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#include "mq.h"
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PRIVATE int running;
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/*===========================================================================*
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* blockdriver_receive_mq *
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*===========================================================================*/
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PUBLIC int blockdriver_receive_mq(message *m_ptr, int *status_ptr)
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{
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/* receive() interface for drivers with message queueing. */
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/* Any queued messages? */
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if (mq_dequeue(MQ_SINGLE, m_ptr, status_ptr))
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return OK;
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/* Fall back to standard receive() interface otherwise. */
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return driver_receive(ANY, m_ptr, status_ptr);
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}
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/*===========================================================================*
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* blockdriver_terminate *
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*===========================================================================*/
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PUBLIC void blockdriver_terminate(void)
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{
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/* Break out of the main driver loop after finishing the current request. */
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running = FALSE;
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}
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/*===========================================================================*
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* blockdriver_task *
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*===========================================================================*/
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PUBLIC void blockdriver_task(struct blockdriver *bdp)
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{
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/* Main program of any block device driver task. */
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int r, ipc_status;
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message mess;
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running = TRUE;
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/* Here is the main loop of the disk task. It waits for a message, carries
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* it out, and sends a reply.
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*/
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while (running) {
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if ((r = blockdriver_receive_mq(&mess, &ipc_status)) != OK)
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panic("blockdriver_receive_mq failed: %d", r);
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blockdriver_process(bdp, &mess, ipc_status);
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}
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}
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/*===========================================================================*
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* blockdriver_process *
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*===========================================================================*/
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PUBLIC void blockdriver_process(struct blockdriver *bdp, message *m_ptr,
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int ipc_status)
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{
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/* Handle the given received message. */
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int r;
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/* Process the notification or request. */
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if (is_ipc_notify(ipc_status)) {
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blockdriver_handle_notify(bdp, m_ptr);
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/* Do not reply to notifications. */
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} else {
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r = blockdriver_handle_request(bdp, m_ptr);
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blockdriver_reply(m_ptr, ipc_status, r);
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}
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}
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/*===========================================================================*
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* blockdriver_mq_queue *
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*===========================================================================*/
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PUBLIC int blockdriver_mq_queue(message *m, int status)
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{
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/* Queue a message for later processing. */
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return mq_enqueue(MQ_SINGLE, m, status);
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}
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