/* rdsread.c - rdsread */

#include 

/*------------------------------------------------------------------------
 * rdsread  -  Read a block from a remote disk
 *------------------------------------------------------------------------
 */
devcall rdsread (
          struct dentry *devptr,        /* Entry in device switch table */
          char  *buff,                  /* Buffer to hold disk block    */
          int32 blk                     /* Block num. of block to read  */
        )
{
        struct  rdscblk *rdptr;         /* Pointer to the control block */
                                        /*   for the disk device        */
        struct  rdsent  *sptr;          /* Pointer to serial queue entry*/

        /* If the device not currently open, report an error */

        rdptr = &rdstab[devptr->dvminor];
        if (rdptr->rd_state != RD_OPEN) {
                return SYSERR;
        }

        /* Obtain the next serial queue entry and fill it in */

        sptr = &rdptr->rd_sq[rdptr->rdstail++];
        if (rdptr->rdstail >= RD_SSIZE) {  /* wrap around, if necessary */
                rdptr->rdstail = 0;
        }
        rdptr->rdscount++;              /* Increment the count of items */
        sptr->rd_op = RD_OP_READ;
        sptr->rd_blknum = blk;
        sptr->rd_callbuf = buff;
        sptr->rd_pid = getpid();

        /* Atomically resume the communication process and suspend the  */
        /*  the current process to wait for the read to complete        */

        rdsars(rdptr->rd_comproc);
        return RD_BLKSIZ;
}