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minix/servers/mfs/device.c

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#include "fs.h"
#include <fcntl.h>
#include <assert.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include <minix/ioctl.h>
#include <minix/safecopies.h>
#include <minix/u64.h>
#include <string.h>
#include "inode.h"
#include "super.h"
#include "const.h"
#include "drivers.h"
#include <minix/vfsif.h>
PRIVATE int dummyproc;
FORWARD _PROTOTYPE( int safe_io_conversion, (endpoint_t,
cp_grant_id_t *, int *, cp_grant_id_t *, int, endpoint_t *,
void **, int *, vir_bytes));
FORWARD _PROTOTYPE( void safe_io_cleanup, (cp_grant_id_t, cp_grant_id_t *,
int));
FORWARD _PROTOTYPE( int gen_opcl, (endpoint_t driver_e, int op,
Dev_t dev, int proc_e, int flags) );
FORWARD _PROTOTYPE( int gen_io, (endpoint_t task_nr, message *mess_ptr) );
/*===========================================================================*
* fs_new_driver *
*===========================================================================*/
PUBLIC int fs_new_driver(void)
{
/* New driver endpoint for this device */
driver_endpoints[(fs_m_in.REQ_DEV >> MAJOR) & BYTE].driver_e =
fs_m_in.REQ_DRIVER_E;
return(OK);
}
/*===========================================================================*
* safe_io_conversion *
*===========================================================================*/
PRIVATE int safe_io_conversion(driver, gid, op, gids, gids_size,
io_ept, buf, vec_grants, bytes)
endpoint_t driver;
cp_grant_id_t *gid;
int *op;
cp_grant_id_t *gids;
int gids_size;
endpoint_t *io_ept;
void **buf;
int *vec_grants;
vir_bytes bytes;
{
int j;
iovec_t *v;
static iovec_t *new_iovec;
STATICINIT(new_iovec, NR_IOREQS);
/* Number of grants allocated in vector I/O. */
*vec_grants = 0;
/* Driver can handle it - change request to a safe one. */
*gid = GRANT_INVALID;
switch(*op) {
case MFS_DEV_READ:
case MFS_DEV_WRITE:
/* Change to safe op. */
*op = *op == MFS_DEV_READ ? DEV_READ_S : DEV_WRITE_S;
if((*gid=cpf_grant_direct(driver, (vir_bytes) *buf, bytes,
*op == DEV_READ_S?CPF_WRITE:CPF_READ))<0) {
panic("cpf_grant_magic of buffer failed");
}
break;
case MFS_DEV_GATHER:
case MFS_DEV_SCATTER:
/* Change to safe op. */
*op = *op == MFS_DEV_GATHER ? DEV_GATHER_S : DEV_SCATTER_S;
/* Grant access to my new i/o vector. */
if((*gid = cpf_grant_direct(driver, (vir_bytes) new_iovec,
bytes * sizeof(iovec_t),
CPF_READ | CPF_WRITE)) < 0) {
panic("cpf_grant_direct of vector failed");
}
v = (iovec_t *) *buf;
/* Grant access to i/o buffers. */
for(j = 0; j < bytes; j++) {
if(j >= NR_IOREQS)
panic("vec too big: %d", bytes);
new_iovec[j].iov_addr = gids[j] =
cpf_grant_direct(driver, (vir_bytes) v[j].iov_addr,
v[j].iov_size,
*op == DEV_GATHER_S ? CPF_WRITE : CPF_READ);
if(!GRANT_VALID(gids[j])) {
panic("mfs: grant to iovec buf failed");
}
new_iovec[j].iov_size = v[j].iov_size;
(*vec_grants)++;
}
/* Set user's vector to the new one. */
*buf = new_iovec;
break;
}
/* If we have converted to a safe operation, I/O
* endpoint becomes FS if it wasn't already.
*/
if(GRANT_VALID(*gid)) {
*io_ept = SELF_E;
return 1;
}
/* Not converted to a safe operation (because there is no
* copying involved in this operation).
*/
return 0;
}
/*===========================================================================*
* safe_io_cleanup *
*===========================================================================*/
PRIVATE void safe_io_cleanup(gid, gids, gids_size)
cp_grant_id_t gid;
cp_grant_id_t *gids;
int gids_size;
{
/* Free resources (specifically, grants) allocated by safe_io_conversion(). */
int j;
cpf_revoke(gid);
for(j = 0; j < gids_size; j++)
cpf_revoke(gids[j]);
return;
}
/*===========================================================================*
* block_dev_io *
*===========================================================================*/
PUBLIC int block_dev_io(op, dev, proc_e, buf, pos, bytes, flags)
int op; /* MFS_DEV_READ, MFS_DEV_WRITE, etc. */
dev_t dev; /* major-minor device number */
int proc_e; /* in whose address space is buf? */
void *buf; /* virtual address of the buffer */
u64_t pos; /* byte position */
int bytes; /* how many bytes to transfer */
int flags; /* special flags, like O_NONBLOCK */
{
/* Read or write from a device. The parameter 'dev' tells which one. */
int r, safe;
message m;
cp_grant_id_t gid = GRANT_INVALID;
int vec_grants;
int op_used;
void *buf_used;
static cp_grant_id_t *gids;
endpoint_t driver_e;
STATICINIT(gids, NR_IOREQS);
/* Determine driver endpoint for this device */
driver_e = driver_endpoints[(dev >> MAJOR) & BYTE].driver_e;
/* See if driver is roughly valid. */
if (driver_e == NONE) {
printf("MFS(%d) block_dev_io: no driver for dev %x\n", SELF_E, dev);
return(EDEADSRCDST);
}
/* The io vector copying relies on this I/O being for FS itself. */
if(proc_e != SELF_E) {
printf("MFS(%d) doing block_dev_io for non-self %d\n", SELF_E, proc_e);
panic("doing block_dev_io for non-self: %d", proc_e);
}
/* By default, these are right. */
m.IO_ENDPT = proc_e;
m.ADDRESS = buf;
buf_used = buf;
/* Convert parameters to 'safe mode'. */
op_used = op;
safe = safe_io_conversion(driver_e, &gid,
&op_used, gids, NR_IOREQS, &m.IO_ENDPT, &buf_used,
&vec_grants, bytes);
/* Set up rest of the message. */
if (safe) m.IO_GRANT = (char *) gid;
m.m_type = op_used;
m.DEVICE = (dev >> MINOR) & BYTE;
m.POSITION = ex64lo(pos);
m.COUNT = bytes;
m.HIGHPOS = ex64hi(pos);
/* Call the task. */
r = sendrec(driver_e, &m);
/* As block I/O never SUSPENDs, safe cleanup must be done whether
* the I/O succeeded or not. */
if (safe) safe_io_cleanup(gid, gids, vec_grants);
/* RECOVERY:
* - send back dead driver number
* - VFS unmaps it, waits for new driver
* - VFS sends the new driver endp for the FS proc and the request again
*/
if (r != OK) {
if (r == EDEADSRCDST) {
printf("MFS(%d) dead driver %d\n", SELF_E, driver_e);
driver_endpoints[(dev >> MAJOR) & BYTE].driver_e = NONE;
return r;
/*dmap_unmap_by_endpt(task_nr); <- in the VFS proc... */
}
else if (r == ELOCKED) {
printf("MFS(%d) ELOCKED talking to %d\n", SELF_E, driver_e);
return r;
}
else
panic("call_task: can't send/receive: %d", r);
}
else {
/* Did the process we did the sendrec() for get a result? */
if (m.REP_ENDPT != proc_e) {
printf("MFS(%d) strange device reply from %d, type = %d, proc = %d (not %d) (2) ignored\n", SELF_E, m.m_source, m.m_type, proc_e, m.REP_ENDPT);
r = EIO;
}
}
/* Task has completed. See if call completed. */
if (m.REP_STATUS == SUSPEND) {
panic("MFS block_dev_io: driver returned SUSPEND");
}
if(buf != buf_used && r == OK) {
memcpy(buf, buf_used, bytes * sizeof(iovec_t));
}
return(m.REP_STATUS);
}
/*===========================================================================*
* dev_open *
*===========================================================================*/
PUBLIC int dev_open(driver_e, dev, proc, flags)
endpoint_t driver_e;
dev_t dev; /* device to open */
int proc; /* process to open for */
int flags; /* mode bits and flags */
{
int major, r;
/* Determine the major device number call the device class specific
* open/close routine. (This is the only routine that must check the
* device number for being in range. All others can trust this check.)
*/
major = (dev >> MAJOR) & BYTE;
if (major >= NR_DEVICES) major = 0;
r = gen_opcl(driver_e, DEV_OPEN, dev, proc, flags);
if (r == SUSPEND) panic("suspend on open from");
return(r);
}
/*===========================================================================*
* dev_close *
*===========================================================================*/
PUBLIC void dev_close(driver_e, dev)
endpoint_t driver_e;
dev_t dev; /* device to close */
{
(void) gen_opcl(driver_e, DEV_CLOSE, dev, 0, 0);
}
/*===========================================================================*
* gen_opcl *
*===========================================================================*/
PRIVATE int gen_opcl(driver_e, op, dev, proc_e, flags)
endpoint_t driver_e;
int op; /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev; /* device to open or close */
int proc_e; /* process to open/close for */
int flags; /* mode bits and flags */
{
/* Called from the dmap struct in table.c on opens & closes of special files.*/
message dev_mess;
dev_mess.m_type = op;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
dev_mess.IO_ENDPT = proc_e;
dev_mess.COUNT = flags;
/* Call the task. */
gen_io(driver_e, &dev_mess);
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* gen_io *
*===========================================================================*/
PRIVATE int gen_io(
endpoint_t task_nr, /* which task to call */
message *mess_ptr /* pointer to message for task */
)
{
/* All file system I/O ultimately comes down to I/O on major/minor device
* pairs. These lead to calls on the following routines via the dmap table.
*/
int r, proc_e;
proc_e = mess_ptr->IO_ENDPT;
r = sendrec(task_nr, mess_ptr);
if (r != OK) {
if (r == EDEADSRCDST) {
printf("fs: dead driver %d\n", task_nr);
panic("should handle crashed drivers");
/* dmap_unmap_by_endpt(task_nr); */
return r;
}
if (r == ELOCKED) {
printf("fs: ELOCKED talking to %d\n", task_nr);
return r;
}
panic("call_task: can't send/receive: %d", r);
}
/* Did the process we did the sendrec() for get a result? */
if (mess_ptr->REP_ENDPT != proc_e) {
printf(
"fs: strange device reply from %d, type = %d, proc = %d (not %d) (2) ignored\n",
mess_ptr->m_source,
mess_ptr->m_type,
proc_e,
mess_ptr->REP_ENDPT);
return(EIO);
}
return(OK);
}
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