[bug report] dm: add emulated block size target

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Heinz Mauelshagen,

The patch d3d11ad3d087: "dm: add emulated block size target" from Mar
9, 2020, leads to the following static checker warning:

	drivers/md/dm-ebs-target.c:190 __ebs_process_bios()
	warn: assigning signed to unsigned: 'bio->bi_status = r' '(-4095)-0'

drivers/md/dm-ebs-target.c
   173                          if (__block_mod(bio_end_sector(bio), ec->u_bs) && block2 != block1)
   174                                  dm_bufio_prefetch(ec->bufio, block2, 1);
   175                  }
   176          }
   177  
   178          bio_list_for_each(bio, &bios) {
   179                  r = -EIO;
   180                  if (bio_op(bio) == REQ_OP_READ)
   181                          r = __ebs_rw_bio(ec, READ, bio);
   182                  else if (bio_op(bio) == REQ_OP_WRITE) {
   183                          write = true;
   184                          r = __ebs_rw_bio(ec, WRITE, bio);
   185                  } else if (bio_op(bio) == REQ_OP_DISCARD) {
   186                          /* FIXME: (optionally) call dm_bufio_discard_buffers() once upstream. */
   187                          r = __ebs_forget_bio(ec, bio);
   188                  }
   189  
   190                  bio->bi_status = r;
                        ^^^^^^^^^^^^^^^^^^
"r" is a negative error code and ->bi_status is a u8 so this won't work.

   191          }
   192  
   193          /*
   194           * We write dirty buffers after processing I/O on them
   195           * but before we endio thus addressing REQ_FUA/REQ_SYNC.
   196           */
   197          r = write ? dm_bufio_write_dirty_buffers(ec->bufio) : 0;

regards,
dan carpenter