Hi Bart, > > +static unsigned int ufshpb_host_map_kbytes = 1024; > > A comment that explains where this value comes from would be welcome. I will add a follows comment and change defalut value 1024 to 2048. "A cache size of 2MB can cache ppn in the 1GB range." > > +static struct ufshpb_req *ufshpb_get_map_req(struct ufshpb_lu *hpb, > > + struct ufshpb_subregion *srgn) > > +{ > > + struct ufshpb_req *map_req; > > + struct request *req; > > + struct bio *bio; > > + > > + map_req = kmem_cache_alloc(hpb->map_req_cache, GFP_KERNEL); > > + if (!map_req) > > + return NULL; > > + > > + req = blk_get_request(hpb->sdev_ufs_lu->request_queue, > > + REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT); > > Why BLK_MQ_REQ_PREEMPT? Since this code is only executed while medium access > commands are processed and since none of these commands have the PREEMPT flag > set I think that the PREEMPT flag should be left out. Otherwise there probably > will be weird interactions with runtime suspended devices. OK, I will remove BLK_MQ_REQ_PREEMPT flag. > Is it acceptable that the above blk_get_request() call blocks if a UFS device > has been runtime suspended? If not, consider using the flag BLK_MQ_REQ_NOWAIT > instead. The map worker don't issue map requests when the UFS device is in runtime suspend. So, I think BLK_MQ_REQ_NOWAIT flags is not needed. > > + bio = bio_alloc(GFP_KERNEL, hpb->pages_per_srgn); > > + if (!bio) { > > + blk_put_request(req); > > + goto free_map_req; > > + } > > If the blk_get_request() would be modified such that it doesn't wait, this > call may have to be modified too (GFP_NOWAIT?). > > > + if (rgn->rgn_state == HPB_RGN_INACTIVE) { > > + if (atomic_read(&lru_info->active_cnt) > > + == lru_info->max_lru_active_cnt) { > > When splitting a line, please put comparison operators at the end of the line > instead of at the start, e.g. as follows: > > if (atomic_read(&lru_info->active_cnt) == > lru_info->max_lru_active_cnt) { OK, I will change it. > > + pool_size = DIV_ROUND_UP(ufshpb_host_map_kbytes * 1024, PAGE_SIZE); > > Please use PAGE_ALIGN() to align to the next page boundary. OK, I will. Thanks, Daejun.