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minix3/lib/libblockdriver/driver.c

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/* This file contains the device independent block driver interface.
*
* Block drivers support the following requests. Message format m10 is used.
* Field names are prefixed with BDEV_. Separate field names are used for the
* "access", "request", and "user" fields.
*
* m_type MINOR COUNT GRANT FLAGS ID REQUEST POS
* +--------------+--------+----------+-------+-------+------+---------+------+
* | BDEV_OPEN | minor | access | | | id | | |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_CLOSE | minor | | | | id | | |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_READ | minor | bytes | grant | flags | id | | pos. |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_WRITE | minor | bytes | grant | flags | id | | pos. |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_GATHER | minor | elements | grant | flags | id | | pos. |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_SCATTER | minor | elements | grant | flags | id | | pos. |
* |--------------+--------+----------+-------+-------+------+---------+------|
* | BDEV_IOCTL | minor | | grant | user | id | request | |
* ----------------------------------------------------------------------------
*
* The following reply message is used for all requests.
*
* m_type STATUS ID
* +--------------+--------+----------+-------+-------+------+---------+------+
* | BDEV_REPLY | status | | | | id | | |
* ----------------------------------------------------------------------------
*
* Changes:
* Oct 16, 2011 split character and block protocol (D.C. van Moolenbroek)
* Aug 27, 2011 move common functions into driver.c (A. Welzel)
* Jul 25, 2005 added SYS_SIG type for signals (Jorrit N. Herder)
* Sep 15, 2004 added SYN_ALARM type for timeouts (Jorrit N. Herder)
* Jul 23, 2004 removed kernel dependencies (Jorrit N. Herder)
* Apr 02, 1992 constructed from AT wini and floppy driver (Kees J. Bot)
*/
#include <minix/drivers.h>
#include <minix/blockdriver.h>
#include <minix/ds.h>
#include <sys/ioc_block.h>
#include <sys/ioc_disk.h>
#include "driver.h"
#include "mq.h"
#include "trace.h"
/* Management data for opened devices. */
static int open_devs[MAX_NR_OPEN_DEVICES];
static int next_open_devs_slot = 0;
/*===========================================================================*
* clear_open_devs *
*===========================================================================*/
static void clear_open_devs(void)
{
/* Reset the set of previously opened minor devices. */
next_open_devs_slot = 0;
}
/*===========================================================================*
* is_open_dev *
*===========================================================================*/
static int is_open_dev(int device)
{
/* Check whether the given minor device has previously been opened. */
int i;
for (i = 0; i < next_open_devs_slot; i++)
if (open_devs[i] == device)
return TRUE;
return FALSE;
}
/*===========================================================================*
* set_open_dev *
*===========================================================================*/
static void set_open_dev(int device)
{
/* Mark the given minor device as having been opened. */
if (next_open_devs_slot >= MAX_NR_OPEN_DEVICES)
panic("out of slots for open devices");
open_devs[next_open_devs_slot] = device;
next_open_devs_slot++;
}
/*===========================================================================*
* blockdriver_announce *
*===========================================================================*/
void blockdriver_announce(int type)
{
/* Announce we are up after a fresh start or a restart. */
int r;
char key[DS_MAX_KEYLEN];
char label[DS_MAX_KEYLEN];
char *driver_prefix = "drv.blk.";
/* Callers are allowed to use ipc_sendrec to communicate with drivers.
* For this reason, there may blocked callers when a driver restarts.
* Ask the kernel to unblock them (if any). Note that most block drivers
* will not restart statefully, and thus will skip this code.
*/
if (type == SEF_INIT_RESTART) {
if ((r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS)) != OK)
panic("blockdriver_init: sys_statectl failed: %d", r);
}
/* Publish a driver up event. */
if ((r = ds_retrieve_label_name(label, sef_self())) != OK)
panic("blockdriver_init: unable to get own label: %d", r);
snprintf(key, DS_MAX_KEYLEN, "%s%s", driver_prefix, label);
if ((r = ds_publish_u32(key, DS_DRIVER_UP, DSF_OVERWRITE)) != OK)
panic("blockdriver_init: unable to publish driver up event: %d", r);
/* Expect an open for any device before serving regular driver requests. */
clear_open_devs();
/* Initialize or reset the message queue. */
mq_init();
}
/*===========================================================================*
* send_reply *
*===========================================================================*/
static void send_reply(endpoint_t endpt, message *m_ptr, int ipc_status)
{
/* Send a reply message to a request. */
int r;
/* If we would block sending the message, send it asynchronously. The NOREPLY
* flag is set because the caller may also issue a SENDREC (mixing sync and
* async comm), and the asynchronous reply could otherwise end up satisfying
* the SENDREC's receive part, after which our next SENDNB call would fail.
*/
if (IPC_STATUS_CALL(ipc_status) == SENDREC)
r = ipc_sendnb(endpt, m_ptr);
else
r = asynsend3(endpt, m_ptr, AMF_NOREPLY);
if (r != OK)
printf("blockdriver: unable to send reply to %d: %d\n", endpt, r);
}
/*===========================================================================*
* blockdriver_reply *
*===========================================================================*/
void blockdriver_reply(message *m_ptr, int ipc_status, int reply)
{
/* Reply to a block request sent to the driver. */
message m_reply;
if (reply == EDONTREPLY)
return;
memset(&m_reply, 0, sizeof(m_reply));
m_reply.m_type = BDEV_REPLY;
m_reply.m_lblockdriver_lbdev_reply.status = reply;
m_reply.m_lblockdriver_lbdev_reply.id = m_ptr->m_lbdev_lblockdriver_msg.id;
send_reply(m_ptr->m_source, &m_reply, ipc_status);
}
/*===========================================================================*
* do_open *
*===========================================================================*/
static int do_open(struct blockdriver *bdp, message *mp)
{
/* Open a minor device. */
return (*bdp->bdr_open)(mp->m_lbdev_lblockdriver_msg.minor, mp->m_lbdev_lblockdriver_msg.access);
}
/*===========================================================================*
* do_close *
*===========================================================================*/
static int do_close(struct blockdriver *bdp, message *mp)
{
/* Close a minor device. */
return (*bdp->bdr_close)(mp->m_lbdev_lblockdriver_msg.minor);
}
/*===========================================================================*
* do_rdwt *
*===========================================================================*/
static int do_rdwt(struct blockdriver *bdp, message *mp)
{
/* Carry out a single read or write request. */
iovec_t iovec1;
u64_t position;
int do_write;
ssize_t r;
/* Disk address? Address and length of the user buffer? */
if (mp->m_lbdev_lblockdriver_msg.count < 0) return EINVAL;
/* Create a one element scatter/gather vector for the buffer. */
iovec1.iov_addr = mp->m_lbdev_lblockdriver_msg.grant;
iovec1.iov_size = mp->m_lbdev_lblockdriver_msg.count;
/* Transfer bytes from/to the device. */
do_write = (mp->m_type == BDEV_WRITE);
position = mp->m_lbdev_lblockdriver_msg.pos;
r = (*bdp->bdr_transfer)(mp->m_lbdev_lblockdriver_msg.minor, do_write, position, mp->m_source,
&iovec1, 1, mp->m_lbdev_lblockdriver_msg.flags);
/* Return the number of bytes transferred or an error code. */
return r;
}
/*===========================================================================*
* do_vrdwt *
*===========================================================================*/
static int do_vrdwt(struct blockdriver *bdp, message *mp, thread_id_t id)
{
/* Carry out an device read or write to/from a vector of buffers. */
iovec_t iovec[NR_IOREQS];
unsigned int nr_req;
u64_t position;
int i, do_write;
ssize_t r, size;
/* Copy the vector from the caller to kernel space. */
nr_req = mp->m_lbdev_lblockdriver_msg.count; /* Length of I/O vector */
if (nr_req > NR_IOREQS) nr_req = NR_IOREQS;
if (OK != sys_safecopyfrom(mp->m_source, (vir_bytes) mp->m_lbdev_lblockdriver_msg.grant,
0, (vir_bytes) iovec, nr_req * sizeof(iovec[0]))) {
printf("blockdriver: bad I/O vector by: %d\n", mp->m_source);
return EINVAL;
}
/* Check for overflow condition, and update the size for block tracing. */
for (i = size = 0; i < nr_req; i++) {
if ((ssize_t) (size + iovec[i].iov_size) < size) return EINVAL;
size += iovec[i].iov_size;
}
trace_setsize(id, size);
/* Transfer bytes from/to the device. */
do_write = (mp->m_type == BDEV_SCATTER);
position = mp->m_lbdev_lblockdriver_msg.pos;
r = (*bdp->bdr_transfer)(mp->m_lbdev_lblockdriver_msg.minor, do_write, position, mp->m_source,
iovec, nr_req, mp->m_lbdev_lblockdriver_msg.flags);
/* Return the number of bytes transferred or an error code. */
return r;
}
/*===========================================================================*
* do_dioctl *
*===========================================================================*/
static int do_dioctl(struct blockdriver *bdp, dev_t minor,
unsigned long request, endpoint_t endpt, cp_grant_id_t grant)
{
/* Carry out a disk-specific I/O control request. */
struct device *dv;
struct part_geom entry;
int r = EINVAL;
switch (request) {
case DIOCSETP:
/* Copy just this one partition table entry. */
r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &entry,
sizeof(entry));
if (r != OK)
return r;
if ((dv = (*bdp->bdr_part)(minor)) == NULL)
return ENXIO;
dv->dv_base = entry.base;
dv->dv_size = entry.size;
break;
case DIOCGETP:
/* Return a partition table entry and the geometry of the drive. */
if ((dv = (*bdp->bdr_part)(minor)) == NULL)
return ENXIO;
entry.base = dv->dv_base;
entry.size = dv->dv_size;
if (bdp->bdr_geometry) {
(*bdp->bdr_geometry)(minor, &entry);
} else {
/* The driver doesn't care -- make up fake geometry. */
entry.cylinders = (unsigned long)(entry.size / SECTOR_SIZE) /
(64 * 32);
entry.heads = 64;
entry.sectors = 32;
}
r = sys_safecopyto(endpt, grant, 0, (vir_bytes) &entry, sizeof(entry));
break;
}
return r;
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
static int do_ioctl(struct blockdriver *bdp, message *mp)
{
/* Carry out an I/O control request. We forward block trace control requests
* to the tracing module, and handle setting/getting partitions when the driver
* has specified that it is a disk driver.
*/
dev_t minor;
unsigned long request;
cp_grant_id_t grant;
endpoint_t user_endpt;
int r;
minor = mp->m_lbdev_lblockdriver_msg.minor;
request = mp->m_lbdev_lblockdriver_msg.request;
grant = mp->m_lbdev_lblockdriver_msg.grant;
user_endpt = mp->m_lbdev_lblockdriver_msg.user;
switch (request) {
case BIOCTRACEBUF:
case BIOCTRACECTL:
case BIOCTRACEGET:
/* Block trace control. */
r = trace_ctl(minor, request, mp->m_source, grant);
break;
case DIOCSETP:
case DIOCGETP:
/* Handle disk-specific IOCTLs only for disk-type drivers. */
if (bdp->bdr_type == BLOCKDRIVER_TYPE_DISK) {
/* Disk partition control. */
r = do_dioctl(bdp, minor, request, mp->m_source, grant);
break;
}
/* fall-through */
default:
if (bdp->bdr_ioctl)
r = (*bdp->bdr_ioctl)(minor, request, mp->m_source, grant,
user_endpt);
else
r = ENOTTY;
}
return r;
}
/*===========================================================================*
* do_char_open *
*===========================================================================*/
static void do_char_open(message *m_ptr, int ipc_status)
{
/* Reply to a character driver open request stating there is no such device. */
message m_reply;
memset(&m_reply, 0, sizeof(m_reply));
m_reply.m_type = CDEV_REPLY;
m_reply.m_lchardriver_vfs_reply.status = ENXIO;
m_reply.m_lchardriver_vfs_reply.id = m_ptr->m_vfs_lchardriver_openclose.id;
send_reply(m_ptr->m_source, &m_reply, ipc_status);
}
/*===========================================================================*
* blockdriver_process_on_thread *
*===========================================================================*/
void blockdriver_process_on_thread(struct blockdriver *bdp, message *m_ptr,
int ipc_status, thread_id_t id)
{
/* Call the appropiate driver function, based on the type of request. Send
* a result code to the caller. The call is processed in the context of the
* given thread ID, which may be SINGLE_THREAD for single-threaded callers.
*/
int r;
/* Check for notifications first. We never reply to notifications. */
if (is_ipc_notify(ipc_status)) {
switch (_ENDPOINT_P(m_ptr->m_source)) {
case HARDWARE:
if (bdp->bdr_intr)
(*bdp->bdr_intr)(m_ptr->m_notify.interrupts);
break;
case CLOCK:
if (bdp->bdr_alarm)
(*bdp->bdr_alarm)(m_ptr->m_notify.timestamp);
break;
default:
if (bdp->bdr_other)
(*bdp->bdr_other)(m_ptr, ipc_status);
}
return; /* do not send a reply */
}
/* Reply to character driver open requests with an error code. Otherwise, if
* someone creates a character device node for a block driver, opening that
* device node will cause the corresponding VFS thread to block forever.
*/
if (m_ptr->m_type == CDEV_OPEN) {
do_char_open(m_ptr, ipc_status);
return;
}
/* We might get spurious requests if the driver has been restarted. Deny any
* requests on devices that have not previously been opened, signaling the
* caller that something went wrong.
*/
if (IS_BDEV_RQ(m_ptr->m_type) && !is_open_dev(m_ptr->m_lbdev_lblockdriver_msg.minor)) {
/* Reply ERESTART to spurious requests for unopened devices. */
if (m_ptr->m_type != BDEV_OPEN) {
blockdriver_reply(m_ptr, ipc_status, ERESTART);
return;
}
/* Mark the device as opened otherwise. */
set_open_dev(m_ptr->m_lbdev_lblockdriver_msg.minor);
}
trace_start(id, m_ptr);
/* Call the appropriate function(s) for this request. */
switch (m_ptr->m_type) {
case BDEV_OPEN: r = do_open(bdp, m_ptr); break;
case BDEV_CLOSE: r = do_close(bdp, m_ptr); break;
case BDEV_READ:
case BDEV_WRITE: r = do_rdwt(bdp, m_ptr); break;
case BDEV_GATHER:
case BDEV_SCATTER: r = do_vrdwt(bdp, m_ptr, id); break;
case BDEV_IOCTL: r = do_ioctl(bdp, m_ptr); break;
default:
if (bdp->bdr_other != NULL)
(*bdp->bdr_other)(m_ptr, ipc_status);
return; /* do not send a reply */
}
/* Let the driver perform any cleanup. */
if (bdp->bdr_cleanup != NULL)
(*bdp->bdr_cleanup)();
trace_finish(id, r);
blockdriver_reply(m_ptr, ipc_status, r);
}
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