[PATCHv2 11/11] nvme: use fdp streams if write stream is provided

[Keith Busch <kbusch@meta.com>]

From: Keith Busch <kbusch@kernel.org>

Maps a user requested write stream to an FDP placement ID if possible.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/core.c | 31 ++++++++++++++++++++++++++++++-
 drivers/nvme/host/nvme.h |  1 +
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c8bc58b8ee3aa..d14c23916671d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -674,6 +674,7 @@ static void nvme_free_ns_head(struct kref *ref)
 	ida_free(&head->subsys->ns_ida, head->instance);
 	cleanup_srcu_struct(&head->srcu);
 	nvme_put_subsystem(head->subsys);
+	kfree(head->plids);
 	kfree(head);
 }
 
@@ -997,6 +998,18 @@ static inline blk_status_t nvme_setup_rw(struct nvme_ns *ns,
 	if (req->cmd_flags & REQ_RAHEAD)
 		dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
 
+	if (op == nvme_cmd_write && ns->head->nr_plids) {
+		u16 write_stream = req->bio->bi_write_stream;
+
+		if (WARN_ON_ONCE(write_stream > ns->head->nr_plids))
+			return BLK_STS_INVAL;
+
+		if (write_stream) {
+			dsmgmt |= ns->head->plids[write_stream - 1] << 16;
+			control |= NVME_RW_DTYPE_DPLCMT;
+		}
+	}
+
 	if (req->cmd_flags & REQ_ATOMIC && !nvme_valid_atomic_write(req))
 		return BLK_STS_INVAL;
 
@@ -2241,7 +2254,7 @@ static int nvme_query_fdp_info(struct nvme_ns *ns, struct nvme_ns_info *info)
 	struct nvme_fdp_config fdp;
 	struct nvme_command c = {};
 	size_t size;
-	int ret;
+	int i, ret;
 
 	/*
 	 * The FDP configuration is static for the lifetime of the namespace,
@@ -2281,6 +2294,22 @@ static int nvme_query_fdp_info(struct nvme_ns *ns, struct nvme_ns_info *info)
 	}
 
 	head->nr_plids = le16_to_cpu(ruhs->nruhsd);
+	if (!head->nr_plids)
+		goto free;
+
+	head->plids = kcalloc(head->nr_plids, sizeof(head->plids),
+			      GFP_KERNEL);
+	if (!head->plids) {
+		dev_warn(ctrl->device,
+			 "failed to allocate %u FDP placement IDs\n",
+			 head->nr_plids);
+		head->nr_plids = 0;
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	for (i = 0; i < head->nr_plids; i++)
+		head->plids[i] = le16_to_cpu(ruhs->ruhsd[i].pid);
 free:
 	kfree(ruhs);
 	return ret;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index b63164cf6b274..59ba31c48cf66 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -498,6 +498,7 @@ struct nvme_ns_head {
 	struct gendisk		*disk;
 
 	u16			nr_plids;
+	u16			*plids;
 #ifdef CONFIG_NVME_MULTIPATH
 	struct bio_list		requeue_list;
 	spinlock_t		requeue_lock;
-- 
2.43.5