[PATCH v1 1/1] nvme: zns: cap zone report nr_zones by DMA buffer size

[Xixin Liu <liuxixin@kylinos.cn>]

With Partial Report (PR=1), the Number of Zones (NZ) field in the report
header must equal the number of zone descriptors fully transferred in the
DMA buffer (ZNS Command Set Specification Rev 1.2, section 3.4.2).

nvme_ns_report_zones() does not cap the parse loop by max_in_buf derived
from buflen.  Cap nz with min3() over the device-reported count, nr_zones -
zone_idx, and max_in_buf.

Signed-off-by: Xixin Liu <liuxixin@kylinos.cn>
---
 drivers/nvme/host/zns.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
index 8ed1b6a33454..2a152e87bd76 100644
--- a/drivers/nvme/host/zns.c
+++ b/drivers/nvme/host/zns.c
@@ -155,7 +155,8 @@ static int nvme_zone_parse_entry(struct nvme_ns *ns,
 	struct blk_zone zone = { };
 
 	if ((entry->zt & 0xf) != NVME_ZONE_TYPE_SEQWRITE_REQ) {
-		dev_err(ns->ctrl->device, "invalid zone type %#x\n", entry->zt);
+		dev_err(ns->ctrl->device, "invalid zone type %#x at zone %u\n",
+			entry->zt, idx);
 		return -EINVAL;
 	}
 
@@ -178,7 +179,7 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 	struct nvme_zone_report *report;
 	struct nvme_command c = { };
 	int ret, zone_idx = 0;
-	unsigned int nz, i;
+	unsigned int max_in_buf, nz, i;
 	size_t buflen;
 
 	if (ns->head->ids.csi != NVME_CSI_ZNS)
@@ -188,6 +189,9 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 	if (!report)
 		return -ENOMEM;
 
+	max_in_buf = (buflen - sizeof(struct nvme_zone_report)) /
+		sizeof(struct nvme_zone_descriptor);
+
 	c.zmr.opcode = nvme_cmd_zone_mgmt_recv;
 	c.zmr.nsid = cpu_to_le32(ns->head->ns_id);
 	c.zmr.numd = cpu_to_le32(nvme_bytes_to_numd(buflen));
@@ -207,7 +211,8 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 			goto out_free;
 		}
 
-		nz = min((unsigned int)le64_to_cpu(report->nr_zones), nr_zones);
+		nz = min3((unsigned int)le64_to_cpu(report->nr_zones),
+			  nr_zones - zone_idx, max_in_buf);
 		if (!nz)
 			break;
 
-- 
2.43.0