Re: [PATCH] scsi: ufs: Fix proper API to send HPB pre-request

From: James Bottomley
Date: Thu Oct 28 2021 - 11:22:27 EST


+Jens, Christoph and linux-block

On Thu, 2021-10-28 at 07:36 +0900, Daejun Park wrote:
> This patch addresses the issue of using the wrong API to create a
> pre_request for HPB READ.
> HPB READ candidate that require a pre-request will try to allocate a
> pre-request only during request_timeout_ms (default: 0). Otherwise,
> it is
> passed as normal READ, so deadlock problem can be resolved.
>
> Signed-off-by: Daejun Park <daejun7.park@xxxxxxxxxxx>
> ---
> drivers/scsi/ufs/ufshpb.c | 11 +++++------
> drivers/scsi/ufs/ufshpb.h | 1 +
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
> index 02fb51ae8b25..3117bd47d762 100644
> --- a/drivers/scsi/ufs/ufshpb.c
> +++ b/drivers/scsi/ufs/ufshpb.c
> @@ -548,8 +548,7 @@ static int ufshpb_execute_pre_req(struct
> ufshpb_lu *hpb, struct scsi_cmnd *cmd,
> read_id);
> rq->cmd_len = scsi_command_size(rq->cmd);
>
> - if (blk_insert_cloned_request(q, req) != BLK_STS_OK)
> - return -EAGAIN;
> + blk_execute_rq_nowait(NULL, req, true,
> ufshpb_pre_req_compl_fn);
>
> hpb->stats.pre_req_cnt++;
>
> @@ -2315,19 +2314,19 @@ struct attribute_group
> ufs_sysfs_hpb_param_group = {
> static int ufshpb_pre_req_mempool_init(struct ufshpb_lu *hpb)
> {
> struct ufshpb_req *pre_req = NULL, *t;
> - int qd = hpb->sdev_ufs_lu->queue_depth / 2;
> int i;
>
> INIT_LIST_HEAD(&hpb->lh_pre_req_free);
>
> - hpb->pre_req = kcalloc(qd, sizeof(struct ufshpb_req),
> GFP_KERNEL);
> - hpb->throttle_pre_req = qd;
> + hpb->pre_req = kcalloc(HPB_INFLIGHT_PRE_REQ, sizeof(struct
> ufshpb_req),
> + GFP_KERNEL);
> + hpb->throttle_pre_req = HPB_INFLIGHT_PRE_REQ;
> hpb->num_inflight_pre_req = 0;
>
> if (!hpb->pre_req)
> goto release_mem;
>
> - for (i = 0; i < qd; i++) {
> + for (i = 0; i < HPB_INFLIGHT_PRE_REQ; i++) {
> pre_req = hpb->pre_req + i;
> INIT_LIST_HEAD(&pre_req->list_req);
> pre_req->req = NULL;
> diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
> index a79e07398970..411a6d625f53 100644
> --- a/drivers/scsi/ufs/ufshpb.h
> +++ b/drivers/scsi/ufs/ufshpb.h
> @@ -50,6 +50,7 @@
> #define HPB_RESET_REQ_RETRIES 10
> #define HPB_MAP_REQ_RETRIES 5
> #define HPB_REQUEUE_TIME_MS 0
> +#define HPB_INFLIGHT_PRE_REQ 4
>
> #define HPB_SUPPORT_VERSION 0x200
> #define HPB_SUPPORT_LEGACY_VERSION 0x100