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Sun, 14 Jun 2026 13:16:09 +0000 (GMT) Received: from li-a84c74cc-2b13-11b2-a85c-acdd023f0674.ibm.com.com (unknown [9.43.80.1]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Sun, 14 Jun 2026 13:16:09 +0000 (GMT) From: Nilay Shroff To: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Cc: hch@lst.de, kbusch@kernel.org, sagi@grimberg.me, axboe@fb.com, bvanassche@acm.org, elver@google.com, gjoyce@linux.ibm.com, Nilay Shroff Subject: [PATCHv2 07/17] nvme: add Clang context annotations for nvme_subsystem::lock Date: Sun, 14 Jun 2026 18:45:22 +0530 Message-ID: <20260614131541.2017845-8-nilay@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260614131541.2017845-1-nilay@linux.ibm.com> References: <20260614131541.2017845-1-nilay@linux.ibm.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 X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: 9HgWC8Hy5YI3wCc52a8EIP2O5vMpLlzs X-Authority-Analysis: v=2.4 cv=XdK5Co55 c=1 sm=1 tr=0 ts=6a2ea9a1 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=Ww_8d8in9Fx9J81-FmEA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjE0MDEzMCBTYWx0ZWRfX8/2CUTFhOmD9 Nw8jubFautCCIo2QNcULgQEJ5GX6Pfa4u+SNeyH8fkpmcaINWVy4aPztxvLVP4PSIBvbB+Y92qD QJaKiun/9WQEbDIr6ObtrB8SvL6cUjZmHcoVXXfh6bYW/RpJCfBoj56tc2fBnv5qCwy424/qCGv rHVgmInERuUyIV5TN3RotdOWZ24aoXlS5Ha23fYe7q47egHMNSyrvqnh0HaFDG//btwAz1L0SCG ZPHlTpH0Hp/3ZofOfX5qT2Mj69hNdyDhWYZfpW9RZNeTG2XKvRfPDtsDkkOFaXXvvFcrVKNNNck Al53Noebw8guQnvULGy6/LbemfY70fUVkBQav3gyCS4BBIFVHlTJMNF2Jc9W57d5StbnwYaQbHg VOUNHicp66NFgC4ZwzdWQ4IKVgCDRWZmyA9RCJdjadSEJCREP31RuPU+upNE5nqPXpJf7/1I3SC TszKZzACzN/8yX7vNIw== X-Proofpoint-ORIG-GUID: ubZ0vlZB17av_EmKFzaa08hUFrxWdIF6 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjE0MDEzMCBTYWx0ZWRfX2yuHrL479t1C KCWifykfVtA21WQd16nCg85SDf3xngFEcnwXXmbhJWT24XOp3bQtzhGIqBykGtzdHqCSJ3ZW2EM 2y0HplZPhhttapKh6MvbCjNYTqlfE88= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-14_03,2026-06-12_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 bulkscore=0 malwarescore=0 spamscore=0 phishscore=0 priorityscore=1501 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606040000 definitions=main-2606140130 Several helpers access or traverse data structures protected by nvme_subsystem::lock and therefore require callers to hold the lock. Annotate nvme_mpath_unfreeze(), nvme_mpath_wait_freeze(), nvme_mpath_start_freeze(), nvme_find_ns_head(), nvme_alloc_ns_head() and nvme_subsys_check_duplicate_ids() with __must_hold(&subsys->lock) so that Clang's lock context analysis can validate the locking requirements at compile time. Also annotate nvme_subsystem::nsheads and nvme_ns_head::delayed_removal_secs with __guarded_by(&subsys->lock), as both are protected by the subsystem lock. Replace mutex_init(&subsys->lock) with scoped_guard(mutex_init, &subsys->lock) so that Clang's context analysis can observe the synthetic acquisition and release of subsys->lock during initialization of the guarded nvme_subsystem::nsheads list in nvme_init_subsystem(). The initialization of delayed_removal_secs in nvme_mpath_alloc_disk() occurs before the namespace head is published and therefore does not require synchronization. So annotate the delayed_removal_secs initialization with context_unsafe() to suppress the corresponding context analysis warning. Signed-off-by: Nilay Shroff --- drivers/nvme/host/core.c | 7 +++++-- drivers/nvme/host/multipath.c | 9 ++++++++- drivers/nvme/host/nvme.h | 13 ++++++++----- 3 files changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index d6153c3e0007..341753a4be85 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3247,10 +3247,10 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id) return -ENOMEM; subsys->instance = -1; - mutex_init(&subsys->lock); + scoped_guard(mutex_init, &subsys->lock) + INIT_LIST_HEAD(&subsys->nsheads); kref_init(&subsys->ref); INIT_LIST_HEAD(&subsys->ctrls); - INIT_LIST_HEAD(&subsys->nsheads); nvme_init_subnqn(subsys, ctrl, id); memcpy(subsys->serial, id->sn, sizeof(subsys->serial)); memcpy(subsys->model, id->mn, sizeof(subsys->model)); @@ -3809,6 +3809,7 @@ static const struct file_operations nvme_dev_fops = { static struct nvme_ns_head *nvme_find_ns_head(struct nvme_ctrl *ctrl, unsigned nsid) + __must_hold(&ctrl->subsys->lock) { struct nvme_ns_head *h; @@ -3831,6 +3832,7 @@ static struct nvme_ns_head *nvme_find_ns_head(struct nvme_ctrl *ctrl, static int nvme_subsys_check_duplicate_ids(struct nvme_subsystem *subsys, struct nvme_ns_ids *ids) + __must_hold(&subsys->lock) { bool has_uuid = !uuid_is_null(&ids->uuid); bool has_nguid = memchr_inv(ids->nguid, 0, sizeof(ids->nguid)); @@ -3922,6 +3924,7 @@ static int nvme_add_ns_cdev(struct nvme_ns *ns) static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl, struct nvme_ns_info *info) + __must_hold(&ctrl->subsys->lock) { struct nvme_ns_head *head; size_t size = sizeof(*head); diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 94607c5d1a2b..e816d88ffeee 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -719,7 +719,14 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head) INIT_WORK(&head->requeue_work, nvme_requeue_work); INIT_WORK(&head->partition_scan_work, nvme_partition_scan_work); INIT_DELAYED_WORK(&head->remove_work, nvme_remove_head_work); - head->delayed_removal_secs = 0; + /* + * The namespace head is not yet visible to other threads, so + * initializing delayed_removal_secs does not require holding + * subsys->lock. So suppress Clang's context analyzer warning by + * annotating initialization of delayed_removal_secs using + * context_unsafe. + */ + context_unsafe(head->delayed_removal_secs = 0); /* * If "multipath_always_on" is enabled, a multipath node is added diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 41f42f1aee09..be1467bfae28 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -490,7 +490,7 @@ struct nvme_subsystem { struct list_head entry; struct mutex lock; struct list_head ctrls; - struct list_head nsheads; + struct list_head nsheads __guarded_by(&lock); char subnqn[NVMF_NQN_SIZE]; char serial[20]; char model[40]; @@ -562,7 +562,7 @@ struct nvme_ns_head { struct mutex lock; unsigned long flags; struct delayed_work remove_work; - unsigned int delayed_removal_secs; + unsigned int delayed_removal_secs __guarded_by(&subsys->lock); #define NVME_NSHEAD_DISK_LIVE 0 #define NVME_NSHEAD_QUEUE_IF_NO_PATH 1 struct nvme_ns __rcu_guarded *current_path[]; @@ -1025,9 +1025,12 @@ static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl) return ctrl->ana_log_buf != NULL; } -void nvme_mpath_unfreeze(struct nvme_subsystem *subsys); -void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys); -void nvme_mpath_start_freeze(struct nvme_subsystem *subsys); +void nvme_mpath_unfreeze(struct nvme_subsystem *subsys) + __must_hold(&subsys->lock); +void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys) + __must_hold(&subsys->lock); +void nvme_mpath_start_freeze(struct nvme_subsystem *subsys) + __must_hold(&subsys->lock); void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys); void nvme_failover_req(struct request *req); void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl); -- 2.53.0