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));
/*===========================================================================*
* fs_clone_opcl *
*===========================================================================*/
PUBLIC int fs_clone_opcl(void)
{
/* A new minor device number has been returned.
* Create a temporary device file to hold it.
*/
struct inode *ip;
dev_t dev;
dev = fs_m_in.REQ_DEV; /* Device number */
ip = alloc_inode(fs_dev, ALL_MODES | I_CHAR_SPECIAL);
if (ip == NIL_INODE) return err_code;
ip->i_zone[0] = dev;
fs_m_out.m_source = ip->i_dev;
fs_m_out.RES_INODE_NR = ip->i_num;
fs_m_out.RES_MODE = ip->i_mode;
return OK;
}
/*===========================================================================*
* 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 access = 0, size;
int j;
iovec_t *v;
static iovec_t 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(__FILE__,
"cpf_grant_magic of buffer failed\n", NO_NUM);
}
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(__FILE__,
"cpf_grant_direct of vector failed", NO_NUM);
}
v = (iovec_t *) *buf;
/* Grant access to i/o buffers. */
for(j = 0; j < bytes; j++) {
if(j >= NR_IOREQS)
panic(__FILE__, "vec too big", 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(__FILE__, "mfs: grant to iovec buf failed",
NO_NUM);
}
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. */
struct dmap *dp;
int r, safe;
message m;
iovec_t *v;
cp_grant_id_t gid = GRANT_INVALID;
int vec_grants;
int op_used;
void *buf_used;
static cp_grant_id_t gids[NR_IOREQS];
endpoint_t driver_e;
/* 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 EDSTDIED;
}
/* 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(__FILE__, "doing block_dev_io for non-self", 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 dirver endp for the FS proc and the request again
*/
if (r != OK) {
if (r == EDEADSRCDST || r == EDSTDIED || r == ESRCDIED) {
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(__FILE__,"call_task: can't send/receive", 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(__FILE__, "MFS block_dev_io: driver returned SUSPEND", NO_NUM);
}
if(buf != buf_used && r == OK) {
memcpy(buf, buf_used, bytes * sizeof(iovec_t));
}
return(m.REP_STATUS);
}