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Tue, 24 Feb 2026 09:15:02 -0800 (PST) X-Relaying-Domain: purestorage.com Received: from dev-csander.dev.purestorage.com (dev-csander.dev.purestorage.com [10.112.29.101]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id A6FFC3421BC; Tue, 24 Feb 2026 10:15:01 -0700 (MST) Received: by dev-csander.dev.purestorage.com (Postfix, from userid 1557716354) id A2C21E41254; Tue, 24 Feb 2026 10:15:01 -0700 (MST) From: Caleb Sander Mateos To: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Caleb Sander Mateos Subject: [PATCH v3 5/8] nvme: add from0based() helper Date: Tue, 24 Feb 2026 10:14:34 -0700 Message-ID: <20260224171437.3175993-6-csander@purestorage.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260224171437.3175993-1-csander@purestorage.com> References: <20260224171437.3175993-1-csander@purestorage.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The NVMe specifications are big fans of "0's based"/"0-based" fields for encoding values that must be positive. The encoded value is 1 less than the value it represents. nvmet already provides a helper to0based() for encoding 0's based values, so add a corresponding helper to decode these fields on the host side. Suggested-by: Christoph Hellwig Signed-off-by: Caleb Sander Mateos --- drivers/nvme/host/nvme.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 9971045dbc05..ccd5e05dac98 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -760,10 +760,16 @@ static inline sector_t nvme_lba_to_sect(struct nvme_ns_head *head, u64 lba) static inline u32 nvme_bytes_to_numd(size_t len) { return (len >> 2) - 1; } +/* Decode a 2-byte "0's based"/"0-based" field */ +static inline u32 from0based(__le16 value) +{ + return (u32)le16_to_cpu(value) + 1; +} + static inline bool nvme_is_ana_error(u16 status) { switch (status & NVME_SCT_SC_MASK) { case NVME_SC_ANA_TRANSITION: case NVME_SC_ANA_INACCESSIBLE: -- 2.45.2