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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Niklas Cassel <niklas.cassel@wdc.com>,
        Dennis Maisenbacher <dennis.maisenbacher@wdc.com>,
        Chaitanya Kulkarni <kch@nvidia.com>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 094/121] nvmet: fix mar and mor off-by-one errors
Date:   Tue, 13 Sep 2022 16:04:45 +0200
Message-Id: <20220913140401.398486262@linuxfoundation.org>
In-Reply-To: <20220913140357.323297659@linuxfoundation.org>
References: <20220913140357.323297659@linuxfoundation.org>
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From: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>

[ Upstream commit b7e97872a65e1d57b4451769610554c131f37a0a ]

Maximum Active Resources (MAR) and Maximum Open Resources (MOR) are 0's
based vales where a value of 0xffffffff indicates that there is no limit.

Decrement the values that are returned by bdev_max_open_zones and
bdev_max_active_zones as the block layer helpers are not 0's based.
A 0 returned by the block layer helpers indicates no limit, thus convert
it to 0xffffffff (U32_MAX).

Fixes: aaf2e048af27 ("nvmet: add ZBD over ZNS backend support")
Suggested-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Dennis Maisenbacher <dennis.maisenbacher@wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/zns.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/zns.c b/drivers/nvme/target/zns.c
index 235553337fb2d..1466698751c55 100644
--- a/drivers/nvme/target/zns.c
+++ b/drivers/nvme/target/zns.c
@@ -100,6 +100,7 @@ void nvmet_execute_identify_cns_cs_ns(struct nvmet_req *req)
 	struct nvme_id_ns_zns *id_zns;
 	u64 zsze;
 	u16 status;
+	u32 mar, mor;
 
 	if (le32_to_cpu(req->cmd->identify.nsid) == NVME_NSID_ALL) {
 		req->error_loc = offsetof(struct nvme_identify, nsid);
@@ -126,8 +127,20 @@ void nvmet_execute_identify_cns_cs_ns(struct nvmet_req *req)
 	zsze = (bdev_zone_sectors(req->ns->bdev) << 9) >>
 					req->ns->blksize_shift;
 	id_zns->lbafe[0].zsze = cpu_to_le64(zsze);
-	id_zns->mor = cpu_to_le32(bdev_max_open_zones(req->ns->bdev));
-	id_zns->mar = cpu_to_le32(bdev_max_active_zones(req->ns->bdev));
+
+	mor = bdev_max_open_zones(req->ns->bdev);
+	if (!mor)
+		mor = U32_MAX;
+	else
+		mor--;
+	id_zns->mor = cpu_to_le32(mor);
+
+	mar = bdev_max_active_zones(req->ns->bdev);
+	if (!mar)
+		mar = U32_MAX;
+	else
+		mar--;
+	id_zns->mar = cpu_to_le32(mar);
 
 done:
 	status = nvmet_copy_to_sgl(req, 0, id_zns, sizeof(*id_zns));
-- 
2.35.1