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Thu, 26 Feb 2026 11:04:21 -0800 (PST) Received: from c7-smtp-2023.dev.purestorage.com ([208.88.159.128]) by smtp-relay.gmail.com with ESMTPS id d9443c01a7336-2adfb2710bdsm3572105ad.21.2026.02.26.11.04.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Feb 2026 11:04:21 -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 7E3AA342109; Thu, 26 Feb 2026 12:04:20 -0700 (MST) Received: by dev-csander.dev.purestorage.com (Postfix, from userid 1557716354) id 79581E41254; Thu, 26 Feb 2026 12:04:20 -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 v4 5/8] nvme: add from0based() helper Date: Thu, 26 Feb 2026 12:04:12 -0700 Message-ID: <20260226190416.297725-6-csander@purestorage.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260226190416.297725-1-csander@purestorage.com> References: <20260226190416.297725-1-csander@purestorage.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260226_110423_204074_979991DA X-CRM114-Status: GOOD ( 11.90 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org 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