nvme: keep ctrl->namespaces ordered

Various places in the nvme code that rely on ctrl->namespace to be
ordered.  Ensure that the namespae is inserted into the list at the
right position from the start instead of sorting it after the fact.

Fixes: 5233299d4a17 ("NVMe: Implement namespace list scanning")
Reported-by: Anton Eidelman <anton.eidelman@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 6600e138945e28f4cf6989b152736a63cafcefe5..e486845d2c7eb7ba5c2c9bcc393957b7adeebf2b 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -13,7 +13,6 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/backing-dev.h>
-#include <linux/list_sort.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/pr.h>
@@ -3716,15 +3715,6 @@ out_unlock:
        return ret;
 }
 
-static int ns_cmp(void *priv, const struct list_head *a,
-               const struct list_head *b)
-{
-       struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
-       struct nvme_ns *nsb = container_of(b, struct nvme_ns, list);
-
-       return nsa->head->ns_id - nsb->head->ns_id;
-}
-
 struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
        struct nvme_ns *ns, *ret = NULL;
@@ -3745,6 +3735,22 @@ struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 }
 EXPORT_SYMBOL_NS_GPL(nvme_find_get_ns, NVME_TARGET_PASSTHRU);
 
+/*
+ * Add the namespace to the controller list while keeping the list ordered.
+ */
+static void nvme_ns_add_to_ctrl_list(struct nvme_ns *ns)
+{
+       struct nvme_ns *tmp;
+
+       list_for_each_entry_reverse(tmp, &ns->ctrl->namespaces, list) {
+               if (tmp->head->ns_id < ns->head->ns_id) {
+                       list_add(&ns->list, &tmp->list);
+                       return;
+               }
+       }
+       list_add(&ns->list, &ns->ctrl->namespaces);
+}
+
 static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
                struct nvme_ns_ids *ids)
 {
@@ -3795,9 +3801,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
                goto out_unlink_ns;
 
        down_write(&ctrl->namespaces_rwsem);
-       list_add_tail(&ns->list, &ctrl->namespaces);
+       nvme_ns_add_to_ctrl_list(ns);
        up_write(&ctrl->namespaces_rwsem);
-
        nvme_get_ctrl(ctrl);
 
        if (device_add_disk(ctrl->device, ns->disk, nvme_ns_id_attr_groups))
@@ -4080,10 +4085,6 @@ static void nvme_scan_work(struct work_struct *work)
        if (nvme_scan_ns_list(ctrl) != 0)
                nvme_scan_ns_sequential(ctrl);
        mutex_unlock(&ctrl->scan_lock);
-
-       down_write(&ctrl->namespaces_rwsem);
-       list_sort(NULL, &ctrl->namespaces, ns_cmp);
-       up_write(&ctrl->namespaces_rwsem);
 }
 
 /*