Please refer to https://github.com/21cnbao/training/tree/50506cf04bc5616e0c3f3285dbb006c54deb1c53/kernel/drivers/vmem_disk Dongli Zhang (张东立) http://finallyjustice.github.io ________________________________ > From: zyunone@xxxxxxx > Subject: How to rewrite sbull_request in ldd3 for current kernel? > Date: Sat, 19 Mar 2016 21:22:19 +0800 > To: kernelnewbies@xxxxxxxxxxxxxxxxx > > Hi, > I am reading the book, Linux Driver Development 3. > In the chapter on block driver of this book, I need some help to > rewriting the sbull_request since the kernel’s block API was changed. > > The sbull_request code: > /* > * The simple form of the request function. > */ > static void sbull_request(request_queue_t *q) > { > struct request *req; > > while ((req = elv_next_request(q)) != NULL) { > struct sbull_dev *dev = req->rq_disk->private_data; > if (! blk_fs_request(req)) { > printk (KERN_NOTICE "Skip non-fs request\n"); > end_request(req, 0); > continue; > } > sbull_transfer(dev, req->sector, req->current_nr_sectors, > req->buffer, rq_data_dir(req)); > end_request(req, 1); > } > } > > I have rewritten the code above into: > > /* > * The simple form of the request function. > */ > void blkplay_request(struct request_queue *q) > { > struct request *req; > > while (!blk_queue_stopped(q) && > (req = blk_peek_request(q)) != NULL) { > struct blkplay_dev *dev = req->rq_disk->private_data; > blk_start_request(req); > if (req->cmd_type != REQ_TYPE_FS) { > printk (KERN_NOTICE "Skip non-fs request\n"); > blk_end_request(req, -EIO, 0); > continue; > } > > /* I don’t know how to write the statement below */ > blkplay_transfer(dev, req->sector, req->current_nr_sectors, > req->buffer, rq_data_dir(req)); > > blk_end_request_cur(req, 0); > } > } > > > Is the rewrite proper? > > > > The compiler can’t compile it because the request struct no longer has > > the field of ‘sector’ and ‘current_nr_sectors’. I have read the kernel code > > about the request struct, the kernel code said the __data_len and > __sector field of > request struct is internal so that we shouldn’t access them directly. > > How could I rewrite it ? Thanks. > > _______________________________________________ Kernelnewbies mailing > list Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
