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From:   Pankaj Raghav <p.raghav@samsung.com>
To:     axboe@kernel.dk, hch@lst.de, snitzer@redhat.com,
        damien.lemoal@opensource.wdc.com, hare@suse.de,
        Johannes.Thumshirn@wdc.com
Cc:     linux-nvme@lists.infradead.org, dm-devel@redhat.com,
        dsterba@suse.com, jiangbo.365@bytedance.com,
        linux-kernel@vger.kernel.org, gost.dev@samsung.com,
        linux-block@vger.kernel.org, jaegeuk@kernel.org,
        Pankaj Raghav <p.raghav@samsung.com>,
        Luis Chamberlain <mcgrof@kernel.org>
Subject: [PATCH v5 3/7] nvme: zns: Allow ZNS drives that have non-power_of_2
 zone size
Date:   Mon, 23 May 2022 18:15:57 +0200
Message-Id: <20220523161601.58078-4-p.raghav@samsung.com>
In-Reply-To: <20220523161601.58078-1-p.raghav@samsung.com>
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References: <20220523161601.58078-1-p.raghav@samsung.com>
        <CGME20220523161607eucas1p2b6245eafb81dee3e2efbec3ab86a854d@eucas1p2.samsung.com>
Precedence: bulk

Remove the condition which disallows non-power_of_2 zone size ZNS drive
to be updated and use generic method to calculate number of zones
instead of relying on log and shift based calculation on zone size.

The power_of_2 calculation has been replaced directly with generic
calculation without special handling. Both modified functions are not
used in hot paths, they are only used during initialization &
revalidation of the ZNS device.

As rounddown macro from math.h does not work for 32 bit architectures,
round down operation is open coded.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 drivers/nvme/host/zns.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
index 9f81beb4df4e..d92f937d5cb9 100644
--- a/drivers/nvme/host/zns.c
+++ b/drivers/nvme/host/zns.c
@@ -101,13 +101,6 @@ int nvme_update_zone_info(struct nvme_ns *ns, unsigned lbaf)
 	}
 
 	ns->zsze = nvme_lba_to_sect(ns, le64_to_cpu(id->lbafe[lbaf].zsze));
-	if (!is_power_of_2(ns->zsze)) {
-		dev_warn(ns->ctrl->device,
-			"invalid zone size:%llu for namespace:%u\n",
-			ns->zsze, ns->head->ns_id);
-		status = -ENODEV;
-		goto free_data;
-	}
 
 	blk_queue_set_zoned(ns->disk, BLK_ZONED_HM);
 	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
@@ -128,8 +121,13 @@ static void *nvme_zns_alloc_report_buffer(struct nvme_ns *ns,
 	const size_t min_bufsize = sizeof(struct nvme_zone_report) +
 				   sizeof(struct nvme_zone_descriptor);
 
+	/*
+	 * Division is used to calculate nr_zones with no special handling
+	 * for power of 2 zone sizes as this function is not invoked in a
+	 * hot path
+	 */
 	nr_zones = min_t(unsigned int, nr_zones,
-			 get_capacity(ns->disk) >> ilog2(ns->zsze));
+			 div64_u64(get_capacity(ns->disk), ns->zsze));
 
 	bufsize = sizeof(struct nvme_zone_report) +
 		nr_zones * sizeof(struct nvme_zone_descriptor);
@@ -182,6 +180,7 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 	int ret, zone_idx = 0;
 	unsigned int nz, i;
 	size_t buflen;
+	u64 remainder = 0;
 
 	if (ns->head->ids.csi != NVME_CSI_ZNS)
 		return -EINVAL;
@@ -197,7 +196,11 @@ int nvme_ns_report_zones(struct nvme_ns *ns, sector_t sector,
 	c.zmr.zrasf = NVME_ZRASF_ZONE_REPORT_ALL;
 	c.zmr.pr = NVME_REPORT_ZONE_PARTIAL;
 
-	sector &= ~(ns->zsze - 1);
+	/*
+	 * Round down the sector value to the nearest zone start
+	 */
+	div64_u64_rem(sector, ns->zsze, &remainder);
+	sector -= remainder;
 	while (zone_idx < nr_zones && sector < get_capacity(ns->disk)) {
 		memset(report, 0, buflen);
 
-- 
2.25.1