NVMe: Implement namespace list scanning

The NVMe 1.1 specification provides an identify mode to return a
list of active namespaces. This is more efficient to discover which
namespace identifiers are active on a controller, providing potentially
significant improvement in scan time for controllers with sparesly
populated namespaces.

Signed-off-by: Keith Busch <keith.busch@intel.com>
[hch: add quirk for the broken Qemu Identify implementation.  To be relaxed
 later]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit 540c801c65eb58e05e0ca38b6fd644a83d7e2b33)

Orabug: 24583236
Signed-off-by: Ashok Vairavan <ashok.vairavan@oracle.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 4e506649a7fbdc80e2bf569ea3cb756d61e344b7..81606e1de21dca5fc3cbdde92ab7d9912eb9c055 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1186,6 +1186,16 @@ int nvme_identify_ctrl(struct nvme_dev *dev, struct nvme_id_ctrl **id)
        return error;
 }
 
+static int nvme_identify_ns_list(struct nvme_dev *dev, unsigned nsid, __le32 *ns_list)
+{
+       struct nvme_command c = { };
+
+       c.identify.opcode = nvme_admin_identify;
+       c.identify.cns = cpu_to_le32(2);
+       c.identify.nsid = cpu_to_le32(nsid);
+       return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list, 0x1000);
+}
+
 int nvme_identify_ns(struct nvme_dev *dev, unsigned nsid,
                struct nvme_id_ns **id)
 {
@@ -2420,37 +2430,92 @@ static void nvme_ns_remove(struct nvme_ns *ns)
        kref_put(&ns->kref, nvme_free_ns);
 }
 
-static void nvme_scan_namespaces(struct nvme_dev *dev, unsigned nn)
+static void nvme_validate_ns(struct nvme_dev *dev, unsigned nsid)
 {
-       struct nvme_ns *ns, *next;
-       unsigned i;
+       struct nvme_ns *ns;
 
-       for (i = 1; i <= nn; i++) {
-               ns = nvme_find_ns(dev, i);
-               if (ns) {
-                       if (revalidate_disk(ns->disk))
-                               nvme_ns_remove(ns);
+       ns = nvme_find_ns(dev, nsid);
+       if (ns) {
+               if (revalidate_disk(ns->disk))
+                       nvme_ns_remove(ns);
                } else
-                       nvme_alloc_ns(dev, i);
+                       nvme_alloc_ns(dev, nsid);
+}
+
+static int nvme_scan_ns_list(struct nvme_dev *dev, unsigned nn)
+{
+       struct nvme_ns *ns;
+       __le32 *ns_list;
+       unsigned i, j, nsid, prev = 0, num_lists = DIV_ROUND_UP(nn, 1024);
+       int ret = 0;
+
+       ns_list = kzalloc(0x1000, GFP_KERNEL);
+       if (!ns_list)
+               return -ENOMEM;
+
+       for (i = 0; i < num_lists; i++) {
+               ret = nvme_identify_ns_list(dev, prev, ns_list);
+               if (ret)
+                       goto out;
+
+               for (j = 0; j < min(nn, 1024U); j++) {
+                       nsid = le32_to_cpu(ns_list[j]);
+                       if (!nsid)
+                               goto out;
+
+                       nvme_validate_ns(dev, nsid);
+
+                       while (++prev < nsid) {
+                               ns = nvme_find_ns(dev, prev);
+                               if (ns)
+                                       nvme_ns_remove(ns);
+                       }
+               }
+               nn -= j;
        }
+       out:
+               kfree(ns_list);
+               return ret;
+}
+
+static void __nvme_scan_namespaces(struct nvme_dev *dev, unsigned nn)
+{
+       struct nvme_ns *ns, *next;
+       unsigned i;
+
+       for (i = 1; i <= nn; i++)
+               nvme_validate_ns(dev, i);
+
        list_for_each_entry_safe(ns, next, &dev->namespaces, list) {
                if (ns->ns_id > nn)
                        nvme_ns_remove(ns);
        }
+}
+
+void nvme_scan_namespaces(struct nvme_dev *dev)
+{
+       struct nvme_id_ctrl *id;
+       unsigned nn;
+
+       if (nvme_identify_ctrl(dev, &id))
+               return;
+
+       nn = le32_to_cpu(id->nn);
+       if (!nvme_scan_ns_list(dev, nn))
+               goto done;
+       __nvme_scan_namespaces(dev, le32_to_cpup(&id->nn));
+done:
        list_sort(NULL, &dev->namespaces, ns_cmp);
+       kfree(id);
 }
 
 static void nvme_dev_scan(struct work_struct *work)
 {
        struct nvme_dev *dev = container_of(work, struct nvme_dev, scan_work);
-       struct nvme_id_ctrl *ctrl;
 
        if (!dev->tagset.tags)
                return;
-       if (nvme_identify_ctrl(dev, &ctrl))
-               return;
-       nvme_scan_namespaces(dev, le32_to_cpup(&ctrl->nn));
-       kfree(ctrl);
+       nvme_scan_namespaces(dev);
 }
 
 /*