From: Keith Busch <kbusch@kernel.org>
To: Caleb Sander Mateos <csander@purestorage.com>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <kch@nvidia.com>,
linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 6/8] nvme: set discard_granularity from NPDG/NPDA
Date: Thu, 26 Feb 2026 14:20:02 -0700 [thread overview]
Message-ID: <aaC5AkJyqKZJSidf@kbusch-mbp> (raw)
In-Reply-To: <20260226190416.297725-7-csander@purestorage.com>
On Thu, Feb 26, 2026 at 12:04:13PM -0700, Caleb Sander Mateos wrote:
> + if (optperf & 0x2 && nvm && nvm->npdgl)
> + npdg = le32_to_cpu(nvm->npdgl);
> + else if (optperf & 0x1)
> + npdg = from0based(id->npdg);
> + if (optperf & 0x2 && nvm && nvm->npdal)
> + npda = le32_to_cpu(nvm->npdal);
> + else if (optperf)
> + npda = from0based(id->npda);
> + lim->discard_granularity = max(npdg, npda) * lim->logical_block_size;
I suspect some controller could report a very large npdal/npdgl such
that the multiplication result overflows the discard_granularity type,
so let's check with a fallback:
if (check_mul_overflow(max(npdg, npda), lim->logical_block_size, &result))
lim->discard_granularity = U32_MAX & (lim->logical_block_size - 1);
next prev parent reply other threads:[~2026-02-26 21:20 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-26 19:04 [PATCH v4 0/8] nvme: set discard_granularity from NPDG/NPDA Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 1/8] nvme: add preferred I/O size fields to struct nvme_id_ns_nvm Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 2/8] nvme: fold nvme_config_discard() into nvme_update_disk_info() Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 3/8] nvme: update nvme_id_ns OPTPERF constants Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 4/8] nvme: always issue I/O Command Set specific Identify Namespace Caleb Sander Mateos
2026-02-26 21:02 ` Keith Busch
2026-02-26 21:06 ` Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 5/8] nvme: add from0based() helper Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 6/8] nvme: set discard_granularity from NPDG/NPDA Caleb Sander Mateos
2026-02-26 21:20 ` Keith Busch [this message]
2026-02-26 19:04 ` [PATCH v4 7/8] nvmet: use NVME_NS_FEAT_OPTPERF_SHIFT Caleb Sander Mateos
2026-02-26 19:04 ` [PATCH v4 8/8] nvmet: report NPDGL and NPDAL Caleb Sander Mateos
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