[PATCH v3] scsi: ufshpb: Opt out pre-reqs from HPB2.0 flows

From: Avri Altman
Date: Sat Oct 30 2021 - 02:23:29 EST

v1 -> v2:
- forgot to remove ufshpb_set_write_buf_cmd

v2 -> v3:
- restore bMAX_ DATA_SIZE_FOR_HPB_SINGLE_CMD
- remove read_id - it is now always 0
- Ignore ufshpb_prep returned error - does not return -EAGAIN no more

HPB allows its read commands to carry the physical addresses along with
the LBAs, thus allowing less internal L2P-table switches in the device.
HPB1.0 allowed a single LBA, while HPB2.0 increases this capacity up to
255 blocks.

Carrying more than a single record, the read operation is no longer
of type "read" per-se, but some sort of a "hybrid" command - writing the
physical address to the device and reading the required payload.

The HPB JEDEC spec came-up with a dual-command for that operation:
HPB-WRITE-BUFFER (0x2) to write the physical addresses to device, and
HPB-READ to read the payload.

Alas, the current HPB driver design - a single-scsi-LLD-module, has no
other alternative but to spawn the READ10 command into 2 commands:
HPB-WRITE-BUFFER and HPB-READ.
This causes a grat deal of aggrevation to the block layer guys, up to a
point, in which that they were willing to revert the entire HPB driver,
regardless of the huge amount of corporate effort already inversted in
it.

Therefore, remove the pre-req API for now, as a matter of urgency to get
it done before the closing of the merge window.

Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Avri Altman <avri.altman@xxxxxxx>
Tested-by: Avri Altman <avri.altman@xxxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 7 +-
drivers/scsi/ufs/ufshpb.c | 283 +-------------------------------------
drivers/scsi/ufs/ufshpb.h | 2 -
3 files changed, 4 insertions(+), 288 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index f5ba8f953b87..470affdec426 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2767,12 +2767,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)

lrbp->req_abort_skip = false;

- err = ufshpb_prep(hba, lrbp);
- if (err == -EAGAIN) {
- lrbp->cmd = NULL;
- ufshcd_release(hba);
- goto out;
- }
+ ufshpb_prep(hba, lrbp);

ufshcd_comp_scsi_upiu(hba, lrbp);

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index 66b19500844e..3b1a90b1d82a 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -84,16 +84,6 @@ static bool ufshpb_is_supported_chunk(struct ufshpb_lu *hpb, int transfer_len)
return transfer_len <= hpb->pre_req_max_tr_len;
}

-/*
- * In this driver, WRITE_BUFFER CMD support 36KB (len=9) ~ 1MB (len=256) as
- * default. It is possible to change range of transfer_len through sysfs.
- */
-static inline bool ufshpb_is_required_wb(struct ufshpb_lu *hpb, int len)
-{
- return len > hpb->pre_req_min_tr_len &&
- len <= hpb->pre_req_max_tr_len;
-}
-
static bool ufshpb_is_general_lun(int lun)
{
return lun < UFS_UPIU_MAX_UNIT_NUM_ID;
@@ -334,7 +324,7 @@ ufshpb_get_pos_from_lpn(struct ufshpb_lu *hpb, unsigned long lpn, int *rgn_idx,

static void
ufshpb_set_hpb_read_to_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
- __be64 ppn, u8 transfer_len, int read_id)
+ __be64 ppn, u8 transfer_len)
{
unsigned char *cdb = lrbp->cmd->cmnd;
__be64 ppn_tmp = ppn;
@@ -346,256 +336,11 @@ ufshpb_set_hpb_read_to_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
/* ppn value is stored as big-endian in the host memory */
memcpy(&cdb[6], &ppn_tmp, sizeof(__be64));
cdb[14] = transfer_len;
- cdb[15] = read_id;
+ cdb[15] = 0;

lrbp->cmd->cmd_len = UFS_CDB_SIZE;
}

-static inline void ufshpb_set_write_buf_cmd(unsigned char *cdb,
- unsigned long lpn, unsigned int len,
- int read_id)
-{
- cdb[0] = UFSHPB_WRITE_BUFFER;
- cdb[1] = UFSHPB_WRITE_BUFFER_PREFETCH_ID;
-
- put_unaligned_be32(lpn, &cdb[2]);
- cdb[6] = read_id;
- put_unaligned_be16(len * HPB_ENTRY_SIZE, &cdb[7]);
-
- cdb[9] = 0x00; /* Control = 0x00 */
-}
-
-static struct ufshpb_req *ufshpb_get_pre_req(struct ufshpb_lu *hpb)
-{
- struct ufshpb_req *pre_req;
-
- if (hpb->num_inflight_pre_req >= hpb->throttle_pre_req) {
- dev_info(&hpb->sdev_ufs_lu->sdev_dev,
- "pre_req throttle. inflight %d throttle %d",
- hpb->num_inflight_pre_req, hpb->throttle_pre_req);
- return NULL;
- }
-
- pre_req = list_first_entry_or_null(&hpb->lh_pre_req_free,
- struct ufshpb_req, list_req);
- if (!pre_req) {
- dev_info(&hpb->sdev_ufs_lu->sdev_dev, "There is no pre_req");
- return NULL;
- }
-
- list_del_init(&pre_req->list_req);
- hpb->num_inflight_pre_req++;
-
- return pre_req;
-}
-
-static inline void ufshpb_put_pre_req(struct ufshpb_lu *hpb,
- struct ufshpb_req *pre_req)
-{
- pre_req->req = NULL;
- bio_reset(pre_req->bio);
- list_add_tail(&pre_req->list_req, &hpb->lh_pre_req_free);
- hpb->num_inflight_pre_req--;
-}
-
-static void ufshpb_pre_req_compl_fn(struct request *req, blk_status_t error)
-{
- struct ufshpb_req *pre_req = (struct ufshpb_req *)req->end_io_data;
- struct ufshpb_lu *hpb = pre_req->hpb;
- unsigned long flags;
-
- if (error) {
- struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
- struct scsi_sense_hdr sshdr;
-
- dev_err(&hpb->sdev_ufs_lu->sdev_dev, "block status %d", error);
- scsi_command_normalize_sense(cmd, &sshdr);
- dev_err(&hpb->sdev_ufs_lu->sdev_dev,
- "code %x sense_key %x asc %x ascq %x",
- sshdr.response_code,
- sshdr.sense_key, sshdr.asc, sshdr.ascq);
- dev_err(&hpb->sdev_ufs_lu->sdev_dev,
- "byte4 %x byte5 %x byte6 %x additional_len %x",
- sshdr.byte4, sshdr.byte5,
- sshdr.byte6, sshdr.additional_length);
- }
-
- blk_mq_free_request(req);
- spin_lock_irqsave(&hpb->rgn_state_lock, flags);
- ufshpb_put_pre_req(pre_req->hpb, pre_req);
- spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-}
-
-static int ufshpb_prep_entry(struct ufshpb_req *pre_req, struct page *page)
-{
- struct ufshpb_lu *hpb = pre_req->hpb;
- struct ufshpb_region *rgn;
- struct ufshpb_subregion *srgn;
- __be64 *addr;
- int offset = 0;
- int copied;
- unsigned long lpn = pre_req->wb.lpn;
- int rgn_idx, srgn_idx, srgn_offset;
- unsigned long flags;
-
- addr = page_address(page);
- ufshpb_get_pos_from_lpn(hpb, lpn, &rgn_idx, &srgn_idx, &srgn_offset);
-
- spin_lock_irqsave(&hpb->rgn_state_lock, flags);
-
-next_offset:
- rgn = hpb->rgn_tbl + rgn_idx;
- srgn = rgn->srgn_tbl + srgn_idx;
-
- if (!ufshpb_is_valid_srgn(rgn, srgn))
- goto mctx_error;
-
- if (!srgn->mctx)
- goto mctx_error;
-
- copied = ufshpb_fill_ppn_from_page(hpb, srgn->mctx, srgn_offset,
- pre_req->wb.len - offset,
- &addr[offset]);
-
- if (copied < 0)
- goto mctx_error;
-
- offset += copied;
- srgn_offset += copied;
-
- if (srgn_offset == hpb->entries_per_srgn) {
- srgn_offset = 0;
-
- if (++srgn_idx == hpb->srgns_per_rgn) {
- srgn_idx = 0;
- rgn_idx++;
- }
- }
-
- if (offset < pre_req->wb.len)
- goto next_offset;
-
- spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
- return 0;
-mctx_error:
- spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
- return -ENOMEM;
-}
-
-static int ufshpb_pre_req_add_bio_page(struct ufshpb_lu *hpb,
- struct request_queue *q,
- struct ufshpb_req *pre_req)
-{
- struct page *page = pre_req->wb.m_page;
- struct bio *bio = pre_req->bio;
- int entries_bytes, ret;
-
- if (!page)
- return -ENOMEM;
-
- if (ufshpb_prep_entry(pre_req, page))
- return -ENOMEM;
-
- entries_bytes = pre_req->wb.len * sizeof(__be64);
-
- ret = bio_add_pc_page(q, bio, page, entries_bytes, 0);
- if (ret != entries_bytes) {
- dev_err(&hpb->sdev_ufs_lu->sdev_dev,
- "bio_add_pc_page fail: %d", ret);
- return -ENOMEM;
- }
- return 0;
-}
-
-static inline int ufshpb_get_read_id(struct ufshpb_lu *hpb)
-{
- if (++hpb->cur_read_id >= MAX_HPB_READ_ID)
- hpb->cur_read_id = 1;
- return hpb->cur_read_id;
-}
-
-static int ufshpb_execute_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
- struct ufshpb_req *pre_req, int read_id)
-{
- struct scsi_device *sdev = cmd->device;
- struct request_queue *q = sdev->request_queue;
- struct request *req;
- struct scsi_request *rq;
- struct bio *bio = pre_req->bio;
-
- pre_req->hpb = hpb;
- pre_req->wb.lpn = sectors_to_logical(cmd->device,
- blk_rq_pos(scsi_cmd_to_rq(cmd)));
- pre_req->wb.len = sectors_to_logical(cmd->device,
- blk_rq_sectors(scsi_cmd_to_rq(cmd)));
- if (ufshpb_pre_req_add_bio_page(hpb, q, pre_req))
- return -ENOMEM;
-
- req = pre_req->req;
-
- /* 1. request setup */
- blk_rq_append_bio(req, bio);
- req->rq_disk = NULL;
- req->end_io_data = (void *)pre_req;
- req->end_io = ufshpb_pre_req_compl_fn;
-
- /* 2. scsi_request setup */
- rq = scsi_req(req);
- rq->retries = 1;
-
- ufshpb_set_write_buf_cmd(rq->cmd, pre_req->wb.lpn, pre_req->wb.len,
- read_id);
- rq->cmd_len = scsi_command_size(rq->cmd);
-
- if (blk_insert_cloned_request(q, req) != BLK_STS_OK)
- return -EAGAIN;
-
- hpb->stats.pre_req_cnt++;
-
- return 0;
-}
-
-static int ufshpb_issue_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
- int *read_id)
-{
- struct ufshpb_req *pre_req;
- struct request *req = NULL;
- unsigned long flags;
- int _read_id;
- int ret = 0;
-
- req = blk_get_request(cmd->device->request_queue,
- REQ_OP_DRV_OUT | REQ_SYNC, BLK_MQ_REQ_NOWAIT);
- if (IS_ERR(req))
- return -EAGAIN;
-
- spin_lock_irqsave(&hpb->rgn_state_lock, flags);
- pre_req = ufshpb_get_pre_req(hpb);
- if (!pre_req) {
- ret = -EAGAIN;
- goto unlock_out;
- }
- _read_id = ufshpb_get_read_id(hpb);
- spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
-
- pre_req->req = req;
-
- ret = ufshpb_execute_pre_req(hpb, cmd, pre_req, _read_id);
- if (ret)
- goto free_pre_req;
-
- *read_id = _read_id;
-
- return ret;
-free_pre_req:
- spin_lock_irqsave(&hpb->rgn_state_lock, flags);
- ufshpb_put_pre_req(hpb, pre_req);
-unlock_out:
- spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
- blk_put_request(req);
- return ret;
-}
-
/*
* This function will set up HPB read command using host-side L2P map data.
*/
@@ -609,7 +354,6 @@ int ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
__be64 ppn;
unsigned long flags;
int transfer_len, rgn_idx, srgn_idx, srgn_offset;
- int read_id = 0;
int err = 0;

hpb = ufshpb_get_hpb_data(cmd->device);
@@ -685,24 +429,8 @@ int ufshpb_prep(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
dev_err(hba->dev, "get ppn failed. err %d\n", err);
return err;
}
- if (!ufshpb_is_legacy(hba) &&
- ufshpb_is_required_wb(hpb, transfer_len)) {
- err = ufshpb_issue_pre_req(hpb, cmd, &read_id);
- if (err) {
- unsigned long timeout;
-
- timeout = cmd->jiffies_at_alloc + msecs_to_jiffies(
- hpb->params.requeue_timeout_ms);
-
- if (time_before(jiffies, timeout))
- return -EAGAIN;
-
- hpb->stats.miss_cnt++;
- return 0;
- }
- }

- ufshpb_set_hpb_read_to_upiu(hba, lrbp, ppn, transfer_len, read_id);
+ ufshpb_set_hpb_read_to_upiu(hba, lrbp, ppn, transfer_len);

hpb->stats.hit_cnt++;
return 0;
@@ -1841,16 +1569,11 @@ static void ufshpb_lu_parameter_init(struct ufs_hba *hba,
u32 entries_per_rgn;
u64 rgn_mem_size, tmp;

- /* for pre_req */
- hpb->pre_req_min_tr_len = hpb_dev_info->max_hpb_single_cmd + 1;
-
if (ufshpb_is_legacy(hba))
hpb->pre_req_max_tr_len = HPB_LEGACY_CHUNK_HIGH;
else
hpb->pre_req_max_tr_len = HPB_MULTI_CHUNK_HIGH;

- hpb->cur_read_id = 0;
-
hpb->lu_pinned_start = hpb_lu_info->pinned_start;
hpb->lu_pinned_end = hpb_lu_info->num_pinned ?
(hpb_lu_info->pinned_start + hpb_lu_info->num_pinned - 1)
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index a79e07398970..f15d8fdbce2e 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -241,8 +241,6 @@ struct ufshpb_lu {
spinlock_t param_lock;

struct list_head lh_pre_req_free;
- int cur_read_id;
- int pre_req_min_tr_len;
int pre_req_max_tr_len;

/* cached L2P map management worker */
--
2.17.1