block request execution failing on RHEL6.0 (2.6.32-71.el6.x86_64)

ajit jain ajit4mail at
Wed Apr 20 08:36:55 EDT 2011

Hi All,

I have written a func to send a CDB on a scsi device from the kernel. For
that I am getting a request and queueing for execution.
But blk_execute_rq() func is setting errors field of request to 65536 and
sense length is set but all the fields in sense header is

I dont know what I am missing, any suggestion would be great help.

snippet of the code
    rq = blk_get_request(q, rw, __GFP_WAIT);
         goto out;
    if (buflen &&  blk_rq_map_kern(q, rq, buf, buflen, __GFP_WAIT)){
         goto out;
    rq->cmd_len = cmdlen;
    memcpy(rq->cmd, cmd, cmdlen);
    memset(sense, 0, sizeof(sense));
    rq->sense_len = 0;
    rq->sense = sense;
    rq->cmd_type |= REQ_TYPE_BLOCK_PC;
    rq->cmd_type |= REQ_NOMERGE;
    rq->timeout = WRITE_SCSI_TIMEOUT;              //WRITE_SCSI_TIMEOUT is
set to 60 sec
    blk_execute_rq(q, bd_disk, rq, 0);
    error = rq->errors;
    if( error ){
        dbg("error in blk_execute_rq error %d",error);
    } else {
            info("no sense available");


PS:We can not use sg_ioctl interface because code expects user space
application only to invoke sg_ioctl that the reason it does a copyin.
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