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Mon, 09 Nov 2026 03:32:27 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 6A93WNQY29622562 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 Nov 2026 03:32:23 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 89FBF20043; Mon, 9 Nov 2026 03:32:23 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C8FCF20040; Mon, 9 Nov 2026 03:32:18 +0000 (GMT) Received: from li-a84c74cc-2b13-11b2-a85c-acdd023f0674.ibm.com.com (unknown [9.61.101.130]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 9 Nov 2026 03:32:18 +0000 (GMT) From: Nilay Shroff To: kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, axboe@kernel.dk, chaitanyak@nvidia.com Cc: gjoyce@linux.ibm.com, bvanassche@acm.org, elver@google.com, linux-nvme@lists.infradead.org, Nilay Shroff Subject: [PATCH 09/23] nvmet: add context annotation for nvmet_ns::size Date: Mon, 9 Nov 2026 08:58:14 +0530 Message-ID: <20261109033102.982191-34-nilay@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261109033102.982191-25-nilay@linux.ibm.com> References: <20261109033102.982191-25-nilay@linux.ibm.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYxMTA5MDAxMiBTYWx0ZWRfX1W49nE25j53I YqAViOIEAZcos03ci2Q10w+MFGkPYlv9ObSru5H5Xv/Dc88sEhzAo8pSYDxxs18fC0a06C3OC7x ZEa479rwgyecyuSLWreBFM3VeD7A3/Q= X-Authority-Analysis: v=2.4 cv=GISdgeNK c=1 sm=1 tr=0 ts=6af13ecc cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=KwJ8z0Xve6JmAVbpLWoA:9 X-Proofpoint-GUID: 2VHSkQq4c7V2TzrU-3C7hipOV0z3eMZG X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTA5MDAxMiBTYWx0ZWRfX8qsch3W8SwGH qdXrJJ5JO5omqZQ/aXzxde6PzNdjuHeogg35p+WZrwqf20j5ujC/YDLcPvwgTGB2vUSEYBzyowg Td10AL/h1xF3CUyvKpkIIcJijeDmJZ0hK92KJRREPfAkcTRJgVdQrcg1IxASCzm+qqFkQeGthZt FYnpLNErLTTuoNX/DdD9W0CYWMMD/TnrWOzqaj99rd9qbNnEk6nARLJH6BY1EHx1BhHbM9cQx+K VoiSksOYXbXgGX6A7B3j6D4B0m2LuENvA68bYppgbL+3s5afjCFz1xDh63xwT/whXTNH+/4q0Cl pTJHopGxSXsTSWNIyiv+Kv1PoODXo8wvY2/PS6EKwVfXoEr2BRlEvy427HTL6UJh6z3C0ESdWj4 pEbRLKc8QcZVCYTW8gG+jL7Wd4XwLSOE3AyvygKMhxtr5kR6vSfZIXoQcUmrRpHc9oV55p5HSzZ fZ+b5UGRXVK7mBelljg== X-Proofpoint-ORIG-GUID: 4SPIDzZ9WgPrf7JVZD6A_XGquYPH4zpY X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-09_01,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 bulkscore=0 impostorscore=0 clxscore=1015 adultscore=0 priorityscore=1501 phishscore=0 spamscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611090012 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261108_193235_541661_D3F333A6 X-CRM114-Status: GOOD ( 20.54 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" X-Spam-Status: No, score=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 The nvmet_ns::size field is protected by nvmet_subsys::lock. Annotate it with __guarded_by(&subsys->lock) to allow the Clang context analyzer to validate accesses to this field. The I/O hotpath also accesses ns->size without holding subsys->lock. Unlike ns->bdev, which cannot be updated while I/O is in flight due to the namespace reference, ns->size can be modified concurrently by nvmet_ns_revalidate_size_store() or nvmet_file_ns_revalidate(). Consequently, lockless reads may observe a transient value of ns->size, which is acceptable for these access paths. Introduce nvmet_ns_size() to perform these lockless reads using data_race(READ_ONCE()) which would silence KCSAN splat as well as help avoid clang context analyser warning. Use this accessor at the relevant call sites where accessing ns->size without holding subsys->lock is harmless despite concurrent updates. Pair these lockless reads with WRITE_ONCE() for all updates to ns->size. Also use READ_ONCE() in nvmet_ns_revalidate() when reading the old and new size values to detect changes. Signed-off-by: Nilay Shroff --- drivers/nvme/target/admin-cmd.c | 3 ++- drivers/nvme/target/core.c | 4 ++-- drivers/nvme/target/io-cmd-bdev.c | 4 ++-- drivers/nvme/target/io-cmd-file.c | 10 +++++----- drivers/nvme/target/nvmet.h | 4 +++- 5 files changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c index 4302dba7c000..7cdf13351678 100644 --- a/drivers/nvme/target/admin-cmd.c +++ b/drivers/nvme/target/admin-cmd.c @@ -891,7 +891,8 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req) * that out from the underlying device. */ id->ncap = id->nsze = - cpu_to_le64(req->ns->size >> nvmet_ns_blksize_shift(req->ns)); + cpu_to_le64(nvmet_ns_size(req->ns) >> + nvmet_ns_blksize_shift(req->ns)); switch (req->port->ana_state[req->ns->anagrpid]) { case NVME_ANA_INACCESSIBLE: case NVME_ANA_PERSISTENT_LOSS: diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index 2913ed76bc6a..77e2ef211711 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -591,14 +591,14 @@ static void nvmet_p2pmem_ns_add_p2p(struct nvmet_ctrl *ctrl, bool nvmet_ns_revalidate(struct nvmet_ns *ns) { - loff_t oldsize = ns->size; + loff_t oldsize = READ_ONCE(ns->size); if (ns->bdev) nvmet_bdev_ns_revalidate(ns); else nvmet_file_ns_revalidate(ns); - return oldsize != ns->size; + return oldsize != READ_ONCE(ns->size); } int nvmet_ns_enable(struct nvmet_ns *ns) diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c index e950b442ffc6..0ed691387f1c 100644 --- a/drivers/nvme/target/io-cmd-bdev.c +++ b/drivers/nvme/target/io-cmd-bdev.c @@ -115,7 +115,7 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns) return ret; } ns->bdev = file_bdev(ns->bdev_file); - ns->size = bdev_nr_bytes(ns->bdev); + WRITE_ONCE(ns->size, bdev_nr_bytes(ns->bdev)); ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev)); ns->pi_type = 0; @@ -136,7 +136,7 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns) void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns) { - ns->size = bdev_nr_bytes(ns->bdev); + WRITE_ONCE(ns->size, bdev_nr_bytes(ns->bdev)); } u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts) diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c index 90dbfbd16978..224b7423b780 100644 --- a/drivers/nvme/target/io-cmd-file.c +++ b/drivers/nvme/target/io-cmd-file.c @@ -15,7 +15,7 @@ void nvmet_file_ns_revalidate(struct nvmet_ns *ns) { - ns->size = i_size_read(ns->file->f_mapping->host); + WRITE_ONCE(ns->size, i_size_read(ns->file->f_mapping->host)); } void nvmet_file_ns_disable(struct nvmet_ns *ns) @@ -68,7 +68,7 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns) err: fput(ns->file); ns->file = NULL; - ns->size = 0; + WRITE_ONCE(ns->size, 0); ns->blksize_shift = 0; return ret; } @@ -132,7 +132,7 @@ static bool nvmet_file_execute_io(struct nvmet_req *req, int ki_flags) is_sync = true; pos = le64_to_cpu(req->cmd->rw.slba) << nvmet_ns_blksize_shift(req->ns); - if (unlikely(pos + req->transfer_len > req->ns->size)) { + if (unlikely(pos + req->transfer_len > nvmet_ns_size(req->ns))) { ret = -ENOSPC; goto complete; } @@ -301,7 +301,7 @@ static void nvmet_file_execute_discard(struct nvmet_req *req) nvmet_ns_blksize_shift(req->ns); len = le32_to_cpu(range.nlb); len <<= nvmet_ns_blksize_shift(req->ns); - if (offset + len > req->ns->size) { + if (offset + len > nvmet_ns_size(req->ns)) { req->error_slba = le64_to_cpu(range.slba); status = errno_to_nvme_status(req, -ENOSPC); break; @@ -357,7 +357,7 @@ static void nvmet_file_write_zeroes_work(struct work_struct *w) len = (((sector_t)le16_to_cpu(write_zeroes->length) + 1) << nvmet_ns_blksize_shift(req->ns)); - if (unlikely(offset + len > req->ns->size)) { + if (unlikely(offset + len > nvmet_ns_size(req->ns))) { nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC)); return; } diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h index 1ea0566b8eea..59adf99470f8 100644 --- a/drivers/nvme/target/nvmet.h +++ b/drivers/nvme/target/nvmet.h @@ -161,7 +161,8 @@ struct nvmet_ns { __guarded_by(&subsys->lock); u32 blksize_shift __guarded_by(&subsys->lock); - loff_t size; + loff_t size + __guarded_by(&subsys->lock); u8 nguid[16]; uuid_t uuid; u32 anagrpid; @@ -222,6 +223,7 @@ static inline _type nvmet_ns_##_name(struct nvmet_ns *ns) \ } \ NVMET_NS_ACCESSOR_RACE(bool, readonly) +NVMET_NS_ACCESSOR_RACE(loff_t, size) static inline struct nvmet_ns *to_nvmet_ns(struct config_item *item) { -- 2.53.0