-static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset)
-{
- __u64 sector;
- unsigned char *bitmap;
- int bit, i;
-
- /* mmap must have been requested on the command line */
- if(!ubd_do_mmap)
- return(-1);
-
- /* The buffer must be page aligned */
- if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0)
- return(-1);
-
- /* The request must be a page long */
- if((req->current_nr_sectors << 9) != PAGE_SIZE)
- return(-1);
-
- if(dev->cow.file == NULL)
- return(dev->fd);
-
- sector = offset >> 9;
- bitmap = (unsigned char *) dev->cow.bitmap;
- bit = ubd_test_bit(sector, bitmap);
-
- for(i = 1; i < req->current_nr_sectors; i++){
- if(ubd_test_bit(sector + i, bitmap) != bit)
- return(-1);
- }
-
- if(bit || (rq_data_dir(req) == WRITE))
- offset += dev->cow.data_offset;
-
- /* The data on disk must be page aligned */
- if((offset % UBD_MMAP_BLOCK_SIZE) != 0)
- return(-1);
-
- return(bit ? dev->fd : dev->cow.fd);
-}
-
-static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset,
- struct request *req,
- struct io_thread_req *io_req)
-{
- int err;
-
- if(rq_data_dir(req) == WRITE){
- /* Writes are almost no-ops since the new data is already in the
- * host page cache
- */
- dev->map_writes++;
- if(dev->cow.file != NULL)
- cowify_bitmap(io_req->offset, io_req->length,
- &io_req->sector_mask, &io_req->cow_offset,
- dev->cow.bitmap, dev->cow.bitmap_offset,
- io_req->bitmap_words,
- dev->cow.bitmap_len);
- }
- else {
- int w;
-
- if((dev->cow.file != NULL) && (fd == dev->cow.fd))
- w = 0;
- else w = dev->openflags.w;
-
- if((dev->cow.file != NULL) && (fd == dev->fd))
- offset += dev->cow.data_offset;
-
- err = physmem_subst_mapping(req->buffer, fd, offset, w);
- if(err){
- printk("physmem_subst_mapping failed, err = %d\n",
- -err);
- return(1);
- }
- dev->map_reads++;
- }
- io_req->op = UBD_MMAP;
- io_req->buffer = req->buffer;
- return(0);
-}
-