[PATCH v31 3/4] scsi: ufs: Prepare HPB read for cached sub-region

Daejun Park
2021-03-22T06:55:35Z

This patch changes the read I/O to the HPB read I/O.

If the logical address of the read I/O belongs to active sub-region, the
HPB driver modifies the read I/O command to HPB read. It modifies the UPIU
command of UFS instead of modifying the existing SCSI command.

In the HPB version 1.0, the maximum read I/O size that can be converted to
HPB read is 4KB.

The dirty map of the active sub-region prevents an incorrect HPB read that
has stale physical page number which is updated by previous write I/O.

Reviewed-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.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/ufshcd.c | 2 +
drivers/scsi/ufs/ufshpb.c | 257 +++++++++++++++++++++++++++++++++++++-
drivers/scsi/ufs/ufshpb.h | 2 +
3 files changed, 258 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 88280310bb64..a7cf9278965c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2653,6 +2653,8 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)

lrbp->req_abort_skip = false;

+ ufshpb_prep(hba, lrbp);
+
ufshcd_comp_scsi_upiu(hba, lrbp);

err = ufshcd_map_sg(hba, lrbp);
diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index c67acfc8c6bf..f789339f68d9 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -46,6 +46,29 @@ static void ufshpb_set_state(struct ufshpb_lu *hpb, int state)
atomic_set(&hpb->hpb_state, state);
}

+static int ufshpb_is_valid_srgn(struct ufshpb_region *rgn,
+ struct ufshpb_subregion *srgn)
+{
+ return rgn->rgn_state != HPB_RGN_INACTIVE &&
+ srgn->srgn_state == HPB_SRGN_VALID;
+}
+
+static bool ufshpb_is_read_cmd(struct scsi_cmnd *cmd)
+{
+ return req_op(cmd->request) == REQ_OP_READ;
+}
+
+static bool ufshpb_is_write_or_discard_cmd(struct scsi_cmnd *cmd)
+{
+ return op_is_write(req_op(cmd->request)) ||
+ op_is_discard(req_op(cmd->request));
+}
+
+static bool ufshpb_is_support_chunk(int transfer_len)
+{
+ return transfer_len <= HPB_MULTI_CHUNK_HIGH;
+}
+
static bool ufshpb_is_general_lun(int lun)
{
return lun < UFS_UPIU_MAX_UNIT_NUM_ID;
@@ -80,8 +103,8 @@ static void ufshpb_kick_map_work(struct ufshpb_lu *hpb)
}

static bool ufshpb_is_hpb_rsp_valid(struct ufs_hba *hba,
- struct ufshcd_lrb *lrbp,
- struct utp_hpb_rsp *rsp_field)
+ struct ufshcd_lrb *lrbp,
+ struct utp_hpb_rsp *rsp_field)
{
/* Check HPB_UPDATE_ALERT */
if (!(lrbp->ucd_rsp_ptr->header.dword_2 &
@@ -107,6 +130,234 @@ static bool ufshpb_is_hpb_rsp_valid(struct ufs_hba *hba,
return true;
}

+static void ufshpb_set_ppn_dirty(struct ufshpb_lu *hpb, int rgn_idx,
+ int srgn_idx, int srgn_offset, int cnt)
+{
+ struct ufshpb_region *rgn;
+ struct ufshpb_subregion *srgn;
+ int set_bit_len;
+ int bitmap_len;
+
+next_srgn:
+ rgn = hpb->rgn_tbl + rgn_idx;
+ srgn = rgn->srgn_tbl + srgn_idx;
+
+ if (likely(!srgn->is_last))
+ bitmap_len = hpb->entries_per_srgn;
+ else
+ bitmap_len = hpb->last_srgn_entries;
+
+ if ((srgn_offset + cnt) > bitmap_len)
+ set_bit_len = bitmap_len - srgn_offset;
+ else
+ set_bit_len = cnt;
+
+ if (rgn->rgn_state != HPB_RGN_INACTIVE &&
+ srgn->srgn_state == HPB_SRGN_VALID)
+ bitmap_set(srgn->mctx->ppn_dirty, srgn_offset, set_bit_len);
+
+ srgn_offset = 0;
+ if (++srgn_idx == hpb->srgns_per_rgn) {
+ srgn_idx = 0;
+ rgn_idx++;
+ }
+
+ cnt -= set_bit_len;
+ if (cnt > 0)
+ goto next_srgn;
+}
+
+static bool ufshpb_test_ppn_dirty(struct ufshpb_lu *hpb, int rgn_idx,
+ int srgn_idx, int srgn_offset, int cnt)
+{
+ struct ufshpb_region *rgn;
+ struct ufshpb_subregion *srgn;
+ int bitmap_len;
+ int bit_len;
+
+next_srgn:
+ rgn = hpb->rgn_tbl + rgn_idx;
+ srgn = rgn->srgn_tbl + srgn_idx;
+
+ if (likely(!srgn->is_last))
+ bitmap_len = hpb->entries_per_srgn;
+ else
+ bitmap_len = hpb->last_srgn_entries;
+
+ if (!ufshpb_is_valid_srgn(rgn, srgn))
+ return true;
+
+ /*
+ * If the region state is active, mctx must be allocated.
+ * In this case, check whether the region is evicted or
+ * mctx allcation fail.
+ */
+ if (unlikely(!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 true;
+ }
+
+ if ((srgn_offset + cnt) > bitmap_len)
+ bit_len = bitmap_len - srgn_offset;
+ else
+ bit_len = cnt;
+
+ if (find_next_bit(srgn->mctx->ppn_dirty,
+ bit_len, srgn_offset) >= srgn_offset)
+ return true;
+
+ srgn_offset = 0;
+ if (++srgn_idx == hpb->srgns_per_rgn) {
+ srgn_idx = 0;
+ rgn_idx++;
+ }
+
+ cnt -= bit_len;
+ if (cnt > 0)
+ goto next_srgn;
+
+ return false;
+}
+
+static int ufshpb_fill_ppn_from_page(struct ufshpb_lu *hpb,
+ struct ufshpb_map_ctx *mctx, int pos,
+ int len, u64 *ppn_buf)
+{
+ struct page *page;
+ int index, offset;
+ int copied;
+
+ index = pos / (PAGE_SIZE / HPB_ENTRY_SIZE);
+ offset = pos % (PAGE_SIZE / HPB_ENTRY_SIZE);
+
+ if ((offset + len) <= (PAGE_SIZE / HPB_ENTRY_SIZE))
+ copied = len;
+ else
+ copied = (PAGE_SIZE / HPB_ENTRY_SIZE) - offset;
+
+ page = mctx->m_page[index];
+ if (unlikely(!page)) {
+ dev_err(&hpb->sdev_ufs_lu->sdev_dev,
+ "error. cannot find page in mctx\n");
+ return -ENOMEM;
+ }
+
+ memcpy(ppn_buf, page_address(page) + (offset * HPB_ENTRY_SIZE),
+ copied * HPB_ENTRY_SIZE);
+
+ return copied;
+}
+
+static void
+ufshpb_get_pos_from_lpn(struct ufshpb_lu *hpb, unsigned long lpn, int *rgn_idx,
+ int *srgn_idx, int *offset)
+{
+ int rgn_offset;
+
+ *rgn_idx = lpn >> hpb->entries_per_rgn_shift;
+ rgn_offset = lpn & hpb->entries_per_rgn_mask;
+ *srgn_idx = rgn_offset >> hpb->entries_per_srgn_shift;
+ *offset = rgn_offset & hpb->entries_per_srgn_mask;
+}
+
+static void
+ufshpb_set_hpb_read_to_upiu(struct ufshpb_lu *hpb, struct ufshcd_lrb *lrbp,
+ u32 lpn, u64 ppn, unsigned int transfer_len)
+{
+ unsigned char *cdb = lrbp->cmd->cmnd;
+
+ cdb[0] = UFSHPB_READ;
+
+ /* ppn value is stored as big-endian in the host memory */
+ memcpy(&cdb[6], &ppn, sizeof(u64));
+ cdb[14] = transfer_len;
+
+ lrbp->cmd->cmd_len = UFS_CDB_SIZE;
+}
+
+/*
+ * This function will set up HPB read command using host-side L2P map data.
+ * In HPB v1.0, maximum size of HPB read command is 4KB.
+ */
+void ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
+{
+ struct ufshpb_lu *hpb;
+ struct ufshpb_region *rgn;
+ struct ufshpb_subregion *srgn;
+ struct scsi_cmnd *cmd = lrbp->cmd;
+ u32 lpn;
+ u64 ppn;
+ unsigned long flags;
+ int transfer_len, rgn_idx, srgn_idx, srgn_offset;
+ int err = 0;
+
+ hpb = ufshpb_get_hpb_data(cmd->device);
+ if (!hpb)
+ return;
+
+ if (ufshpb_get_state(hpb) == HPB_INIT)
+ return;
+
+ if (ufshpb_get_state(hpb) != HPB_PRESENT) {
+ dev_notice(&hpb->sdev_ufs_lu->sdev_dev,
+ "%s: ufshpb state is not PRESENT", __func__);
+ return;
+ }
+
+ if (blk_rq_is_scsi(cmd->request) ||
+ (!ufshpb_is_write_or_discard_cmd(cmd) &&
+ !ufshpb_is_read_cmd(cmd)))
+ return 0;
+
+ transfer_len = sectors_to_logical(cmd->device,
+ blk_rq_sectors(cmd->request));
+ if (unlikely(!transfer_len))
+ return;
+
+ lpn = sectors_to_logical(cmd->device, blk_rq_pos(cmd->request));
+ ufshpb_get_pos_from_lpn(hpb, lpn, &rgn_idx, &srgn_idx, &srgn_offset);
+ rgn = hpb->rgn_tbl + rgn_idx;
+ srgn = rgn->srgn_tbl + srgn_idx;
+
+ /* If command type is WRITE or DISCARD, set bitmap as drity */
+ if (ufshpb_is_write_or_discard_cmd(cmd)) {
+ spin_lock_irqsave(&hpb->rgn_state_lock, flags);
+ ufshpb_set_ppn_dirty(hpb, rgn_idx, srgn_idx, srgn_offset,
+ transfer_len);
+ spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
+ return;
+ }
+
+ if (!ufshpb_is_support_chunk(transfer_len))
+ return;
+
+ spin_lock_irqsave(&hpb->rgn_state_lock, flags);
+ if (ufshpb_test_ppn_dirty(hpb, rgn_idx, srgn_idx, srgn_offset,
+ transfer_len)) {
+ hpb->stats.miss_cnt++;
+ spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
+ return;
+ }
+
+ err = ufshpb_fill_ppn_from_page(hpb, srgn->mctx, srgn_offset, 1, &ppn);
+ spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
+ if (unlikely(err < 0)) {
+ /*
+ * In this case, the region state is active,
+ * but the ppn table is not allocated.
+ * Make sure that ppn table must be allocated on
+ * active state.
+ */
+ dev_err(hba->dev, "get ppn failed. err %d\n", err);
+ return;
+ }
+
+ ufshpb_set_hpb_read_to_upiu(hpb, lrbp, lpn, ppn, transfer_len);
+
+ hpb->stats.hit_cnt++;
+}
static struct ufshpb_req *ufshpb_get_map_req(struct ufshpb_lu *hpb,
struct ufshpb_subregion *srgn)
{
@@ -153,7 +404,7 @@ static struct ufshpb_req *ufshpb_get_map_req(struct ufshpb_lu *hpb,
}

static void ufshpb_put_map_req(struct ufshpb_lu *hpb,
- struct ufshpb_req *map_req)
+ struct ufshpb_req *map_req)
{
bio_put(map_req->bio);
blk_put_request(map_req->req);
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index dcc0ca3b8158..6e6a0252dc15 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -201,6 +201,7 @@ struct ufs_hba;
struct ufshcd_lrb;

#ifndef CONFIG_SCSI_UFS_HPB
+static void ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp) {}
static void ufshpb_rsp_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp) {}
static void ufshpb_resume(struct ufs_hba *hba) {}
static void ufshpb_suspend(struct ufs_hba *hba) {}
@@ -214,6 +215,7 @@ static bool ufshpb_is_allowed(struct ufs_hba *hba) { return false; }
static void ufshpb_get_geo_info(struct ufs_hba *hba, u8 *geo_buf) {}
static void ufshpb_get_dev_info(struct ufs_hba *hba, u8 *desc_buf) {}
#else
+void ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp);
void ufshpb_rsp_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp);
void ufshpb_resume(struct ufs_hba *hba);
void ufshpb_suspend(struct ufs_hba *hba);
--
2.25.1