nvme: synchronize access to ctrl->namespaces

Currently traversal and modification of ctrl->namespaces happens completely
unsynchronized, which can be fixed by the addition of a simple mutex.

Note: nvme_dev_ioctl will be handled in the next patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 27130056136b6addf0ecd8ca5b52f245c2120ecd..a928ad5aabaa75a2c231574c06c47159be621238 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1034,6 +1034,8 @@ static struct nvme_ns *nvme_find_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
        struct nvme_ns *ns;
 
+       lockdep_assert_held(&ctrl->namespaces_mutex);
+
        list_for_each_entry(ns, &ctrl->namespaces, list) {
                if (ns->ns_id == nsid)
                        return ns;
@@ -1049,6 +1051,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
        struct gendisk *disk;
        int node = dev_to_node(ctrl->dev);
 
+       lockdep_assert_held(&ctrl->namespaces_mutex);
+
        ns = kzalloc_node(sizeof(*ns), GFP_KERNEL, node);
        if (!ns)
                return;
@@ -1118,6 +1122,8 @@ static void nvme_ns_remove(struct nvme_ns *ns)
        bool kill = nvme_io_incapable(ns->ctrl) &&
                        !blk_queue_dying(ns->queue);
 
+       lockdep_assert_held(&ns->ctrl->namespaces_mutex);
+
        if (kill)
                blk_set_queue_dying(ns->queue);
        if (ns->disk->flags & GENHD_FL_UP) {
@@ -1188,6 +1194,8 @@ static void __nvme_scan_namespaces(struct nvme_ctrl *ctrl, unsigned nn)
        struct nvme_ns *ns, *next;
        unsigned i;
 
+       lockdep_assert_held(&ctrl->namespaces_mutex);
+
        for (i = 1; i <= nn; i++)
                nvme_validate_ns(ctrl, i);
 
@@ -1205,6 +1213,7 @@ void nvme_scan_namespaces(struct nvme_ctrl *ctrl)
        if (nvme_identify_ctrl(ctrl, &id))
                return;
 
+       mutex_lock(&ctrl->namespaces_mutex);
        nn = le32_to_cpu(id->nn);
        if (ctrl->vs >= NVME_VS(1, 1) &&
            !(ctrl->quirks & NVME_QUIRK_IDENTIFY_CNS)) {
@@ -1214,6 +1223,7 @@ void nvme_scan_namespaces(struct nvme_ctrl *ctrl)
        __nvme_scan_namespaces(ctrl, le32_to_cpup(&id->nn));
  done:
        list_sort(NULL, &ctrl->namespaces, ns_cmp);
+       mutex_unlock(&ctrl->namespaces_mutex);
        kfree(id);
 }
 
@@ -1221,8 +1231,10 @@ void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
 {
        struct nvme_ns *ns, *next;
 
+       mutex_lock(&ctrl->namespaces_mutex);
        list_for_each_entry_safe(ns, next, &ctrl->namespaces, list)
                nvme_ns_remove(ns);
+       mutex_unlock(&ctrl->namespaces_mutex);
 }
 
 static DEFINE_IDA(nvme_instance_ida);
@@ -1290,6 +1302,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
        int ret;
 
        INIT_LIST_HEAD(&ctrl->namespaces);
+       mutex_init(&ctrl->namespaces_mutex);
        kref_init(&ctrl->kref);
        ctrl->dev = dev;
        ctrl->ops = ops;
@@ -1332,6 +1345,7 @@ void nvme_freeze_queues(struct nvme_ctrl *ctrl)
 {
        struct nvme_ns *ns;
 
+       mutex_lock(&ctrl->namespaces_mutex);
        list_for_each_entry(ns, &ctrl->namespaces, list) {
                blk_mq_freeze_queue_start(ns->queue);
 
@@ -1342,18 +1356,21 @@ void nvme_freeze_queues(struct nvme_ctrl *ctrl)
                blk_mq_cancel_requeue_work(ns->queue);
                blk_mq_stop_hw_queues(ns->queue);
        }
+       mutex_unlock(&ctrl->namespaces_mutex);
 }
 
 void nvme_unfreeze_queues(struct nvme_ctrl *ctrl)
 {
        struct nvme_ns *ns;
 
+       mutex_lock(&ctrl->namespaces_mutex);
        list_for_each_entry(ns, &ctrl->namespaces, list) {
                queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, ns->queue);
                blk_mq_unfreeze_queue(ns->queue);
                blk_mq_start_stopped_hw_queues(ns->queue, true);
                blk_mq_kick_requeue_list(ns->queue);
        }
+       mutex_unlock(&ctrl->namespaces_mutex);
 }
 
 int __init nvme_core_init(void)

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 0da67474ce6d97b780a3b9407eb42cb3709d2d90..44375923bd6a100f561535e567d9b987987da8b2 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -69,6 +69,7 @@ struct nvme_ctrl {
        int instance;
        struct blk_mq_tag_set *tagset;
        struct list_head namespaces;
+       struct mutex namespaces_mutex;
        struct device *device;  /* char device */
        struct list_head node;