Re: [PATCH v26 2/4] scsi: ufs: L2P map management for HPB read

Can Guo
2021-03-15T01:55:55Z

On 2021-03-12 15:17, Daejun Park wrote:
>>>> > This is a patch for managing L2P map in HPB module.
>>>> >
>>>> > The HPB divides logical addresses into several regions. A region
>>>> > consists
>>>> > of several sub-regions. The sub-region is a basic unit where L2P
>>>> > mapping is
>>>> > managed. The driver loads L2P mapping data of each sub-region. The
>>>> > loaded
>>>> > sub-region is called active-state. The HPB driver unloads L2P mapping
>>>> > data
>>>> > as region unit. The unloaded region is called inactive-state.
>>>> >
>>>> > Sub-region/region candidates to be loaded and unloaded are delivered
>>>> > from
>>>> > the UFS device. The UFS device delivers the recommended active
>>>> > sub-region
>>>> > and inactivate region to the driver using sensedata.
>>>> > The HPB module performs L2P mapping management on the host through the
>>>> > delivered information.
>>>> >
>>>> > A pinned region is a pre-set regions on the UFS device that is always
>>>> > activate-state.
>>>> >
>>>> > The data structure for map data request and L2P map uses mempool API,
>>>> > minimizing allocation overhead while avoiding static allocation.
>>>> >
>>>> > The mininum size of the memory pool used in the HPB is implemented
>>>> > as a module parameter, so that it can be configurable by the user.
>>>> >
>>>> > To gurantee a minimum memory pool size of 4MB:
>>>> > ufshpb_host_map_kbytes=4096
>>>> >
>>>> > The map_work manages active/inactive by 2 "to-do" lists.
>>>> > Each hpb lun maintains 2 "to-do" lists:
>>>> > hpb->lh_inact_rgn - regions to be inactivated, and
>>>> > hpb->lh_act_srgn - subregions to be activated
>>>> > Those lists are maintained on IO completion.
>>>> >
>>>> > Reviewed-by: Bart Van Assche <bvanassche@acm.org>
>>>> > Reviewed-by: Can Guo <cang@codeaurora.org>
>>>> > Acked-by: Avri Altman <Avri.Altman@wdc.com>
>>>> > Tested-by: Bean Huo <beanhuo@micron.com>
>>>> > Signed-off-by: Daejun Park <daejun7.park@samsung.com>
>>>> > ---
>>>> > drivers/scsi/ufs/ufs.h | 36 ++
>>>> > drivers/scsi/ufs/ufshcd.c | 4 +
>>>> > drivers/scsi/ufs/ufshpb.c | 1091 ++++++++++++++++++++++++++++++++++++-
>>>> > drivers/scsi/ufs/ufshpb.h | 65 +++
>>>> > 4 files changed, 1181 insertions(+), 15 deletions(-)
>>>> >
>>>> > diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
>>>> > index 65563635e20e..957763db1006 100644
>>>> > --- a/drivers/scsi/ufs/ufs.h
>>>> > +++ b/drivers/scsi/ufs/ufs.h
>>>> > @@ -472,6 +472,41 @@ struct utp_cmd_rsp {
>>>> > u8 sense_data[UFS_SENSE_SIZE];
>>>> > };
>>>> >
>>>> > +struct ufshpb_active_field {
>>>> > + __be16 active_rgn;
>>>> > + __be16 active_srgn;
>>>> > +};
>>>> > +#define HPB_ACT_FIELD_SIZE 4
>>>> > +
>>>> > +/**
>>>> > + * struct utp_hpb_rsp - Response UPIU structure
>>>> > + * @residual_transfer_count: Residual transfer count DW-3
>>>> > + * @reserved1: Reserved double words DW-4 to DW-7
>>>> > + * @sense_data_len: Sense data length DW-8 U16
>>>> > + * @desc_type: Descriptor type of sense data
>>>> > + * @additional_len: Additional length of sense data
>>>> > + * @hpb_op: HPB operation type
>>>> > + * @lun: LUN of response UPIU
>>>> > + * @active_rgn_cnt: Active region count
>>>> > + * @inactive_rgn_cnt: Inactive region count
>>>> > + * @hpb_active_field: Recommended to read HPB region and subregion
>>>> > + * @hpb_inactive_field: To be inactivated HPB region and subregion
>>>> > + */
>>>> > +struct utp_hpb_rsp {
>>>> > + __be32 residual_transfer_count;
>>>> > + __be32 reserved1[4];
>>>> > + __be16 sense_data_len;
>>>> > + u8 desc_type;
>>>> > + u8 additional_len;
>>>> > + u8 hpb_op;
>>>> > + u8 lun;
>>>> > + u8 active_rgn_cnt;
>>>> > + u8 inactive_rgn_cnt;
>>>> > + struct ufshpb_active_field hpb_active_field[2];
>>>> > + __be16 hpb_inactive_field[2];
>>>> > +};
>>>> > +#define UTP_HPB_RSP_SIZE 40
>>>> > +
>>>> > /**
>>>> > * struct utp_upiu_rsp - general upiu response structure
>>>> > * @header: UPIU header structure DW-0 to DW-2
>>>> > @@ -482,6 +517,7 @@ struct utp_upiu_rsp {
>>>> > struct utp_upiu_header header;
>>>> > union {
>>>> > struct utp_cmd_rsp sr;
>>>> > + struct utp_hpb_rsp hr;
>>>> > struct utp_upiu_query qr;
>>>> > };
>>>> > };
>>>> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>>> > index 49b3d5d24fa6..5852ff44c3cc 100644
>>>> > --- a/drivers/scsi/ufs/ufshcd.c
>>>> > +++ b/drivers/scsi/ufs/ufshcd.c
>>>> > @@ -5021,6 +5021,9 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba,
>>>> > struct ufshcd_lrb *lrbp)
>>>> > */
>>>> > pm_runtime_get_noresume(hba->dev);
>>>> > }
>>>> > +
>>>> > + if (scsi_status == SAM_STAT_GOOD)
>>>> > + ufshpb_rsp_upiu(hba, lrbp);
>>>> > break;
>>>> > case UPIU_TRANSACTION_REJECT_UPIU:
>>>> > /* TODO: handle Reject UPIU Response */
>>>> > @@ -9221,6 +9224,7 @@ EXPORT_SYMBOL(ufshcd_shutdown);
>>>> > void ufshcd_remove(struct ufs_hba *hba)
>>>> > {
>>>> > ufs_bsg_remove(hba);
>>>> > + ufshpb_remove(hba);
>>>> > ufs_sysfs_remove_nodes(hba->dev);
>>>> > blk_cleanup_queue(hba->tmf_queue);
>>>> > blk_mq_free_tag_set(&hba->tmf_tag_set);
>>>> > diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
>>>> > index 1a72f6541510..8abadb0e010a 100644
>>>> > --- a/drivers/scsi/ufs/ufshpb.c
>>>> > +++ b/drivers/scsi/ufs/ufshpb.c
>>>> > @@ -16,6 +16,16 @@
>>>> > #include "ufshpb.h"
>>>> > #include "../sd.h"
>>>> >
>>>> > +/* memory management */
>>>> > +static struct kmem_cache *ufshpb_mctx_cache;
>>>> > +static mempool_t *ufshpb_mctx_pool;
>>>> > +static mempool_t *ufshpb_page_pool;
>>>> > +/* A cache size of 2MB can cache ppn in the 1GB range. */
>>>> > +static unsigned int ufshpb_host_map_kbytes = 2048;
>>>> > +static int tot_active_srgn_pages;
>>>> > +
>>>> > +static struct workqueue_struct *ufshpb_wq;
>>>> > +
>>>> > bool ufshpb_is_allowed(struct ufs_hba *hba)
>>>> > {
>>>> > return !(hba->ufshpb_dev.hpb_disabled);
>>>> > @@ -36,14 +46,892 @@ static void ufshpb_set_state(struct ufshpb_lu
>>>> > *hpb, int state)
>>>> > atomic_set(&hpb->hpb_state, state);
>>>> > }
>>>> >
>>>> > +static bool ufshpb_is_general_lun(int lun)
>>>> > +{
>>>> > + return lun < UFS_UPIU_MAX_UNIT_NUM_ID;
>>>> > +}
>>>> > +
>>>> > +static bool
>>>> > +ufshpb_is_pinned_region(struct ufshpb_lu *hpb, int rgn_idx)
>>>> > +{
>>>> > + if (hpb->lu_pinned_end != PINNED_NOT_SET &&
>>>> > + rgn_idx >= hpb->lu_pinned_start &&
>>>> > + rgn_idx <= hpb->lu_pinned_end)
>>>> > + return true;
>>>> > +
>>>> > + return false;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_kick_map_work(struct ufshpb_lu *hpb)
>>>> > +{
>>>> > + bool ret = false;
>>>> > + unsigned long flags;
>>>> > +
>>>> > + if (ufshpb_get_state(hpb) != HPB_PRESENT)
>>>> > + return;
>>>> > +
>>>> > + spin_lock_irqsave(&hpb->rsp_list_lock, flags);
>>>> > + if (!list_empty(&hpb->lh_inact_rgn) ||
>>>> > !list_empty(&hpb->lh_act_srgn))
>>>> > + ret = true;
>>>> > + spin_unlock_irqrestore(&hpb->rsp_list_lock, flags);
>>>> > +
>>>> > + if (ret)
>>>> > + queue_work(ufshpb_wq, &hpb->map_work);
>>>> > +}
>>>> > +
>>>> > +static bool ufshpb_is_hpb_rsp_valid(struct ufs_hba *hba,
>>>> > + struct ufshcd_lrb *lrbp,
>>>> > + struct utp_hpb_rsp *rsp_field)
>>>> > +{
>>>> > + /* Check HPB_UPDATE_ALERT */
>>>> > + if (!(lrbp->ucd_rsp_ptr->header.dword_2 &
>>>> > + UPIU_HEADER_DWORD(0, 2, 0, 0)))
>>>> > + return false;
>>>> > +
>>>> > + if (be16_to_cpu(rsp_field->sense_data_len) != DEV_SENSE_SEG_LEN ||
>>>> > + rsp_field->desc_type != DEV_DES_TYPE ||
>>>> > + rsp_field->additional_len != DEV_ADDITIONAL_LEN ||
>>>> > + rsp_field->active_rgn_cnt > MAX_ACTIVE_NUM ||
>>>> > + rsp_field->inactive_rgn_cnt > MAX_INACTIVE_NUM ||
>>>> > + rsp_field->hpb_op == HPB_RSP_NONE ||
>>>> > + (rsp_field->hpb_op == HPB_RSP_REQ_REGION_UPDATE &&
>>>> > + !rsp_field->active_rgn_cnt && !rsp_field->inactive_rgn_cnt))
>>>> > + return false;
>>>> > +
>>>> > + if (!ufshpb_is_general_lun(rsp_field->lun)) {
>>>> > + dev_warn(hba->dev, "ufshpb: lun(%d) not supported\n",
>>>> > + lrbp->lun);
>>>> > + return false;
>>>> > + }
>>>> > +
>>>> > + return true;
>>>> > +}
>>>> > +
>>>> > +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;
>>>> > + int retries = HPB_MAP_REQ_RETRIES;
>>>> > +
>>>> > + map_req = kmem_cache_alloc(hpb->map_req_cache, GFP_KERNEL);
>>>> > + if (!map_req)
>>>> > + return NULL;
>>>> > +
>>>> > +retry:
>>>> > + req = blk_get_request(hpb->sdev_ufs_lu->request_queue,
>>>> > + REQ_OP_SCSI_IN, BLK_MQ_REQ_NOWAIT);
>>>> > +
>>>> > + if ((PTR_ERR(req) == -EWOULDBLOCK) && (--retries > 0)) {
>>>> > + usleep_range(3000, 3100);
>>>> > + goto retry;
>>>> > + }
>>>> > +
>>>> > + if (IS_ERR(req))
>>>> > + goto free_map_req;
>>>> > +
>>>> > + bio = bio_alloc(GFP_KERNEL, hpb->pages_per_srgn);
>>>> > + if (!bio) {
>>>> > + blk_put_request(req);
>>>> > + goto free_map_req;
>>>> > + }
>>>> > +
>>>> > + map_req->hpb = hpb;
>>>> > + map_req->req = req;
>>>> > + map_req->bio = bio;
>>>> > +
>>>> > + map_req->rgn_idx = srgn->rgn_idx;
>>>> > + map_req->srgn_idx = srgn->srgn_idx;
>>>> > + map_req->mctx = srgn->mctx;
>>>> > +
>>>> > + return map_req;
>>>> > +
>>>> > +free_map_req:
>>>> > + kmem_cache_free(hpb->map_req_cache, map_req);
>>>> > + return NULL;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_put_map_req(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_req *map_req)
>>>> > +{
>>>> > + bio_put(map_req->bio);
>>>> > + blk_put_request(map_req->req);
>>>> > + kmem_cache_free(hpb->map_req_cache, map_req);
>>>> > +}
>>>> > +
>>>> > +static int ufshpb_clear_dirty_bitmap(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_subregion *srgn)
>>>> > +{
>>>> > + u32 num_entries = hpb->entries_per_srgn;
>>>> > +
>>>> > + if (!srgn->mctx) {
>>>> > + dev_err(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "no mctx in region %d subregion %d.\n",
>>>> > + srgn->rgn_idx, srgn->srgn_idx);
>>>> > + return -1;
>>>> > + }
>>>> > +
>>>> > + if (unlikely(srgn->is_last))
>>>> > + num_entries = hpb->last_srgn_entries;
>>>> > +
>>>> > + bitmap_zero(srgn->mctx->ppn_dirty, num_entries);
>>>> > + return 0;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_update_active_info(struct ufshpb_lu *hpb, int
>>>> > rgn_idx,
>>>> > + int srgn_idx)
>>>> > +{
>>>> > + struct ufshpb_region *rgn;
>>>> > + struct ufshpb_subregion *srgn;
>>>> > +
>>>> > + rgn = hpb->rgn_tbl + rgn_idx;
>>>> > + srgn = rgn->srgn_tbl + srgn_idx;
>>>> > +
>>>> > + list_del_init(&rgn->list_inact_rgn);
>>>> > +
>>>> > + if (list_empty(&srgn->list_act_srgn))
>>>> > + list_add_tail(&srgn->list_act_srgn, &hpb->lh_act_srgn);
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_update_inactive_info(struct ufshpb_lu *hpb, int
>>>> > rgn_idx)
>>>> > +{
>>>> > + struct ufshpb_region *rgn;
>>>> > + struct ufshpb_subregion *srgn;
>>>> > + int srgn_idx;
>>>> > +
>>>> > + rgn = hpb->rgn_tbl + rgn_idx;
>>>> > +
>>>> > + for_each_sub_region(rgn, srgn_idx, srgn)
>>>> > + list_del_init(&srgn->list_act_srgn);
>>>> > +
>>>> > + if (list_empty(&rgn->list_inact_rgn))
>>>> > + list_add_tail(&rgn->list_inact_rgn, &hpb->lh_inact_rgn);
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_activate_subregion(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_subregion *srgn)
>>>> > +{
>>>> > + struct ufshpb_region *rgn;
>>>> > +
>>>> > + /*
>>>> > + * If there is no mctx in subregion
>>>> > + * after I/O progress for HPB_READ_BUFFER, the region to which the
>>>> > + * subregion belongs was evicted.
>>>> > + * Make sure the region must not evict in I/O progress
>>>> > + */
>>>> > + if (!srgn->mctx) {
>>>> > + dev_err(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "no mctx in region %d subregion %d.\n",
>>>> > + srgn->rgn_idx, srgn->srgn_idx);
>>>> > + srgn->srgn_state = HPB_SRGN_INVALID;
>>>> > + return;
>>>> > + }
>>>> > +
>>>> > + rgn = hpb->rgn_tbl + srgn->rgn_idx;
>>>> > +
>>>> > + if (unlikely(rgn->rgn_state == HPB_RGN_INACTIVE)) {
>>>> > + dev_err(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "region %d subregion %d evicted\n",
>>>> > + srgn->rgn_idx, srgn->srgn_idx);
>>>> > + srgn->srgn_state = HPB_SRGN_INVALID;
>>>> > + return;
>>>> > + }
>>>> > + srgn->srgn_state = HPB_SRGN_VALID;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_map_req_compl_fn(struct request *req, blk_status_t
>>>> > error)
>>>> > +{
>>>> > + struct ufshpb_req *map_req = (struct ufshpb_req *) req->end_io_data;
>>>> > + struct ufshpb_lu *hpb = map_req->hpb;
>>>> > + struct ufshpb_subregion *srgn;
>>>> > + unsigned long flags;
>>>> > +
>>>> > + srgn = hpb->rgn_tbl[map_req->rgn_idx].srgn_tbl +
>>>> > + map_req->srgn_idx;
>>>> > +
>>>> > + ufshpb_clear_dirty_bitmap(hpb, srgn);
>>>> > + spin_lock_irqsave(&hpb->rgn_state_lock, flags);
>>>> > + ufshpb_activate_subregion(hpb, srgn);
>>>> > + spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
>>>> > +
>>>> > + ufshpb_put_map_req(map_req->hpb, map_req);
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_set_read_buf_cmd(unsigned char *cdb, int rgn_idx,
>>>> > + int srgn_idx, int srgn_mem_size)
>>>> > +{
>>>> > + cdb[0] = UFSHPB_READ_BUFFER;
>>>> > + cdb[1] = UFSHPB_READ_BUFFER_ID;
>>>> > +
>>>> > + put_unaligned_be16(rgn_idx, &cdb[2]);
>>>> > + put_unaligned_be16(srgn_idx, &cdb[4]);
>>>> > + put_unaligned_be24(srgn_mem_size, &cdb[6]);
>>>> > +
>>>> > + cdb[9] = 0x00;
>>>> > +}
>>>> > +
>>>> > +static int ufshpb_execute_map_req(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_req *map_req, bool last)
>>>> > +{
>>>> > + struct request_queue *q;
>>>> > + struct request *req;
>>>> > + struct scsi_request *rq;
>>>> > + int mem_size = hpb->srgn_mem_size;
>>>> > + int ret = 0;
>>>> > + int i;
>>>> > +
>>>> > + q = hpb->sdev_ufs_lu->request_queue;
>>>> > + for (i = 0; i < hpb->pages_per_srgn; i++) {
>>>> > + ret = bio_add_pc_page(q, map_req->bio, map_req->mctx->m_page[i],
>>>> > + PAGE_SIZE, 0);
>>>> > + if (ret != PAGE_SIZE) {
>>>> > + dev_err(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "bio_add_pc_page fail %d - %d\n",
>>>> > + map_req->rgn_idx, map_req->srgn_idx);
>>>> > + return ret;
>>>> > + }
>>>> > + }
>>>> > +
>>>> > + req = map_req->req;
>>>> > +
>>>> > + blk_rq_append_bio(req, &map_req->bio);
>>>> > +
>>>> > + req->end_io_data = map_req;
>>>> > +
>>>> > + rq = scsi_req(req);
>>>> > +
>>>> > + if (unlikely(last))
>>>> > + mem_size = hpb->last_srgn_entries * HPB_ENTRY_SIZE;
>>>> > +
>>>> > + ufshpb_set_read_buf_cmd(rq->cmd, map_req->rgn_idx,
>>>> > + map_req->srgn_idx, mem_size);
>>>> > + rq->cmd_len = HPB_READ_BUFFER_CMD_LENGTH;
>>>> > +
>>>> > + blk_execute_rq_nowait(q, NULL, req, 1, ufshpb_map_req_compl_fn);
>>>> > +
>>>> > + hpb->stats.map_req_cnt++;
>>>> > + return 0;
>>>> > +}
>>>> > +
>>>> > +static struct ufshpb_map_ctx *ufshpb_get_map_ctx(struct ufshpb_lu
>>>> > *hpb,
>>>> > + bool last)
>>>> > +{
>>>> > + struct ufshpb_map_ctx *mctx;
>>>> > + u32 num_entries = hpb->entries_per_srgn;
>>>> > + int i, j;
>>>> > +
>>>> > + mctx = mempool_alloc(ufshpb_mctx_pool, GFP_KERNEL);
>>>> > + if (!mctx)
>>>> > + return NULL;
>>>> > +
>>>> > + mctx->m_page = kmem_cache_alloc(hpb->m_page_cache, GFP_KERNEL);
>>>> > + if (!mctx->m_page)
>>>> > + goto release_mctx;
>>>> > +
>>>> > + if (unlikely(last))
>>>> > + num_entries = hpb->last_srgn_entries;
>>>> > +
>>>> > + mctx->ppn_dirty = bitmap_zalloc(num_entries, GFP_KERNEL);
>>>> > + if (!mctx->ppn_dirty)
>>>> > + goto release_m_page;
>>>> > +
>>>> > + for (i = 0; i < hpb->pages_per_srgn; i++) {
>>>> > + mctx->m_page[i] = mempool_alloc(ufshpb_page_pool, GFP_KERNEL);
>>>> > + if (!mctx->m_page[i]) {
>>>> > + for (j = 0; j < i; j++)
>>>> > + mempool_free(mctx->m_page[j], ufshpb_page_pool);
>>>> > + goto release_ppn_dirty;
>>>> > + }
>>>> > + clear_page(page_address(mctx->m_page[i]));
>>>> > + }
>>>> > +
>>>> > + return mctx;
>>>> > +
>>>> > +release_ppn_dirty:
>>>> > + bitmap_free(mctx->ppn_dirty);
>>>> > +release_m_page:
>>>> > + kmem_cache_free(hpb->m_page_cache, mctx->m_page);
>>>> > +release_mctx:
>>>> > + mempool_free(mctx, ufshpb_mctx_pool);
>>>> > + return NULL;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_put_map_ctx(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_map_ctx *mctx)
>>>> > +{
>>>> > + int i;
>>>> > +
>>>> > + for (i = 0; i < hpb->pages_per_srgn; i++)
>>>> > + mempool_free(mctx->m_page[i], ufshpb_page_pool);
>>>> > +
>>>> > + bitmap_free(mctx->ppn_dirty);
>>>> > + kmem_cache_free(hpb->m_page_cache, mctx->m_page);
>>>> > + mempool_free(mctx, ufshpb_mctx_pool);
>>>> > +}
>>>> > +
>>>> > +static int ufshpb_check_srgns_issue_state(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_region *rgn)
>>>> > +{
>>>> > + struct ufshpb_subregion *srgn;
>>>> > + int srgn_idx;
>>>> > +
>>>> > + for_each_sub_region(rgn, srgn_idx, srgn)
>>>> > + if (srgn->srgn_state == HPB_SRGN_ISSUED)
>>>> > + return -EPERM;
>>>> > +
>>>> > + return 0;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_add_lru_info(struct victim_select_info *lru_info,
>>>> > + struct ufshpb_region *rgn)
>>>> > +{
>>>> > + rgn->rgn_state = HPB_RGN_ACTIVE;
>>>> > + list_add_tail(&rgn->list_lru_rgn, &lru_info->lh_lru_rgn);
>>>> > + atomic_inc(&lru_info->active_cnt);
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_hit_lru_info(struct victim_select_info *lru_info,
>>>> > + struct ufshpb_region *rgn)
>>>> > +{
>>>> > + list_move_tail(&rgn->list_lru_rgn, &lru_info->lh_lru_rgn);
>>>> > +}
>>>> > +
>>>> > +static struct ufshpb_region *ufshpb_victim_lru_info(struct ufshpb_lu
>>>> > *hpb)
>>>> > +{
>>>> > + struct victim_select_info *lru_info = &hpb->lru_info;
>>>> > + struct ufshpb_region *rgn, *victim_rgn = NULL;
>>>> > +
>>>> > + list_for_each_entry(rgn, &lru_info->lh_lru_rgn, list_lru_rgn) {
>>>> > + if (!rgn) {
>>>> > + dev_err(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "%s: no region allocated\n",
>>>> > + __func__);
>>>> > + return NULL;
>>>> > + }
>>>> > + if (ufshpb_check_srgns_issue_state(hpb, rgn))
>>>> > + continue;
>>>> > +
>>>> > + victim_rgn = rgn;
>>>> > + break;
>>>> > + }
>>>> > +
>>>> > + return victim_rgn;
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_cleanup_lru_info(struct victim_select_info
>>>> > *lru_info,
>>>> > + struct ufshpb_region *rgn)
>>>> > +{
>>>> > + list_del_init(&rgn->list_lru_rgn);
>>>> > + rgn->rgn_state = HPB_RGN_INACTIVE;
>>>> > + atomic_dec(&lru_info->active_cnt);
>>>> > +}
>>>> > +
>>>> > +static void ufshpb_purge_active_subregion(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_subregion *srgn)
>>>> > +{
>>>> > + if (srgn->srgn_state != HPB_SRGN_UNUSED) {
>>>> > + ufshpb_put_map_ctx(hpb, srgn->mctx);
>>>> > + srgn->srgn_state = HPB_SRGN_UNUSED;
>>>> > + srgn->mctx = NULL;
>>>> > + }
>>>> > +}
>>>> > +
>>>> > +static void __ufshpb_evict_region(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_region *rgn)
>>>> > +{
>>>> > + struct victim_select_info *lru_info;
>>>> > + struct ufshpb_subregion *srgn;
>>>> > + int srgn_idx;
>>>> > +
>>>> > + lru_info = &hpb->lru_info;
>>>> > +
>>>> > + dev_dbg(&hpb->sdev_ufs_lu->sdev_dev, "evict region %d\n",
>>>> > rgn->rgn_idx);
>>>> > +
>>>> > + ufshpb_cleanup_lru_info(lru_info, rgn);
>>>> > +
>>>> > + for_each_sub_region(rgn, srgn_idx, srgn)
>>>> > + ufshpb_purge_active_subregion(hpb, srgn);
>>>> > +}
>>>> > +
>>>> > +static int ufshpb_evict_region(struct ufshpb_lu *hpb, struct
>>>> > ufshpb_region *rgn)
>>>> > +{
>>>> > + unsigned long flags;
>>>> > + int ret = 0;
>>>> > +
>>>> > + spin_lock_irqsave(&hpb->rgn_state_lock, flags);
>>>> > + if (rgn->rgn_state == HPB_RGN_PINNED) {
>>>> > + dev_warn(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "pinned region cannot drop-out. region %d\n",
>>>> > + rgn->rgn_idx);
>>>> > + goto out;
>>>> > + }
>>>> > + if (!list_empty(&rgn->list_lru_rgn)) {
>>>> > + if (ufshpb_check_srgns_issue_state(hpb, rgn)) {
>>>> > + ret = -EBUSY;
>>>> > + goto out;
>>>> > + }
>>>> > +
>>>> > + __ufshpb_evict_region(hpb, rgn);
>>>> > + }
>>>> > +out:
>>>> > + spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
>>>> > + return ret;
>>>> > +}
>>>> > +
>>>> > +static int ufshpb_issue_map_req(struct ufshpb_lu *hpb,
>>>> > + struct ufshpb_region *rgn,
>>>> > + struct ufshpb_subregion *srgn)
>>>> > +{
>>>> > + struct ufshpb_req *map_req;
>>>> > + unsigned long flags;
>>>> > + int ret;
>>>> > + int err = -EAGAIN;
>>>> > + bool alloc_required = false;
>>>> > + enum HPB_SRGN_STATE state = HPB_SRGN_INVALID;
>>>> > +
>>>> > + spin_lock_irqsave(&hpb->rgn_state_lock, flags);
>>>> > +
>>>> > + if (ufshpb_get_state(hpb) != HPB_PRESENT) {
>>>> > + dev_notice(&hpb->sdev_ufs_lu->sdev_dev,
>>>> > + "%s: ufshpb state is not PRESENT\n", __func__);
>>>> > + goto unlock_out;
>>>> > + }
>>>> > +
>>>> > + if ((rgn->rgn_state == HPB_RGN_INACTIVE) &&
>>>> > + (srgn->srgn_state == HPB_SRGN_INVALID)) {
>>>> > + err = 0;
>>>> > + goto unlock_out;
>>>> > + }
>>>> > +
>>>> > + if (srgn->srgn_state == HPB_SRGN_UNUSED)
>>>> > + alloc_required = true;
>>>> > +
>>>> > + /*
>>>> > + * If the subregion is already ISSUED state,
>>>> > + * a specific event (e.g., GC or wear-leveling, etc.) occurs in
>>>> > + * the device and HPB response for map loading is received.
>>>> > + * In this case, after finishing the HPB_READ_BUFFER,
>>>> > + * the next HPB_READ_BUFFER is performed again to obtain the latest
>>>> > + * map data.
>>>> > + */
>>>> > + if (srgn->srgn_state == HPB_SRGN_ISSUED)
>>>> > + goto unlock_out;
>>>> > +
>>>> > + srgn->srgn_state = HPB_SRGN_ISSUED;
>>>> > + spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
>>>> > +
>>>> > + if (alloc_required) {
>>>> > + if (srgn->mctx) {
>>>>
>>>> Can this really happen?
>>>>
>>>> alloc_required is true if srgn->srgn_state == HPB_SRGN_UNUSED.
>>>> ufshpb_put_map_ctx() is called and srgn->srgn_state is given
>>>> HPB_SRGN_UNUSED together in ufshpb_purge_active_subregion().
>>>> Do I miss anything?
>>>
>>> It is not normal case, but it is for preventing memory leak on
>>> abnormal
>>> case.
>>>
>>> Thanks,
>>> Daejun
>>
>> Abnormal how? Could you please give an example?
>
> It is kind of additional memory leak protection. Do you think it is
> unnecessary?

If this can never happen in this code base, then yes it is unnecessary,
since it is dead code. It seems to me like a debug print left there in
early development stage of this change. I am just curious about what
memory leak can happen here. If you are not confident, then please leave
it.

Thanks,
Can Guo.

>
> Thanks,
> Daejun