Re: [PATCH 1/2] nvme: fix racy access to FDP placement ID array

[Kanchan Joshi <joshi.k@samsung.com>]

Hari,

Can you please try this patch and see if this solves what you saw?

  drivers/nvme/host/core.c | 38 +++++++++++++++++---------------------
  drivers/nvme/host/nvme.h |  1 +
  2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 453c1f0b2dd0..09cb22f6509c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2320,14 +2320,6 @@ static int nvme_query_fdp_info(struct nvme_ns 
*ns, struct nvme_ns_info *info)
         size_t size;
         int i, ret;

-       /*
-        * The FDP configuration is static for the lifetime of the 
namespace,
-        * so return immediately if we've already registered this 
namespace's
-        * streams.
-        */
-       if (head->nr_plids)
-               return 0;
-
         ret = nvme_get_features(ctrl, NVME_FEAT_FDP, info->endgid, NULL, 0,
                                 &fdp);
         if (ret) {
@@ -2374,6 +2366,7 @@ static int nvme_query_fdp_info(struct nvme_ns *ns, 
struct nvme_ns_info *info)

         for (i = 0; i < head->nr_plids; i++)
                 head->plids[i] = le16_to_cpu(ruhs->ruhsd[i].pid);
+       head->write_stream_granularity = min(info->runs, U32_MAX);
  free:
         kfree(ruhs);
         return ret;
@@ -2421,12 +2414,6 @@ static int nvme_update_ns_info_block(struct 
nvme_ns *ns,
                         goto out;
         }

-       if (ns->ctrl->ctratt & NVME_CTRL_ATTR_FDPS) {
-               ret = nvme_query_fdp_info(ns, info);
-               if (ret < 0)
-                       goto out;
-       }
-
         if (nvme_invalid_lba_sz(le64_to_cpu(id->nsze),
                         id->lbaf[lbaf].ds - SECTOR_SHIFT, &capacity)) {
                 dev_warn_once(ns->ctrl->device,
@@ -2469,10 +2456,7 @@ static int nvme_update_ns_info_block(struct 
nvme_ns *ns,
                 capacity = 0;

         lim.max_write_streams = ns->head->nr_plids;
-       if (lim.max_write_streams)
-               lim.write_stream_granularity = min(info->runs, U32_MAX);
-       else
-               lim.write_stream_granularity = 0;
+       lim.write_stream_granularity = ns->head->write_stream_granularity;

         /*
          * Only set the DEAC bit if the device guarantees that reads from
@@ -3964,9 +3948,10 @@ static void nvme_add_ns_cdev(struct nvme_ns *ns)
         set_bit(NVME_NS_CDEV_LIVE, &ns->flags);
  }

-static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
+static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ns *ns,
                 struct nvme_ns_info *info)
  {
+       struct nvme_ctrl *ctrl = ns->ctrl;
         struct nvme_ns_head *head;
         size_t size = sizeof(*head);
         int ret = -ENOMEM;
@@ -4002,15 +3987,26 @@ static struct nvme_ns_head 
*nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
         } else
                 head->effects = ctrl->effects;

+       if (ctrl->ctratt & NVME_CTRL_ATTR_FDPS) {
+               ns->head = head;
+               ret = nvme_query_fdp_info(ns, info);
+               if (ret < 0)
+                       goto out_clear_ns_head;
+       }
+
         ret = nvme_mpath_alloc_disk(ctrl, head);
         if (ret)
-               goto out_cleanup_srcu;
+               goto out_cleanup_fdp;

         list_add_tail(&head->entry, &ctrl->subsys->nsheads);

         kref_get(&ctrl->subsys->ref);

         return head;
+out_cleanup_fdp:
+       kfree(head->plids);
+out_clear_ns_head:
+       ns->head = NULL;
  out_cleanup_srcu:
         cleanup_srcu_struct(&head->srcu);
  out_ida_remove:
@@ -4103,7 +4099,7 @@ static int nvme_init_ns_head(struct nvme_ns *ns, 
struct nvme_ns_info *info)
                                 info->nsid);
                         goto out_unlock;
                 }
-               head = nvme_alloc_ns_head(ctrl, info);
+               head = nvme_alloc_ns_head(ns, info);
                 if (IS_ERR(head)) {
                         ret = PTR_ERR(head);
                         goto out_unlock;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 824651cc898d..3ae73b36866d 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -560,6 +560,7 @@ struct nvme_ns_head {

         u16                     nr_plids;
         u16                     *plids;
+       u32                     write_stream_granularity;
  #ifdef CONFIG_NVME_MULTIPATH
         struct bio_list         requeue_list;
         spinlock_t              requeue_lock;
--
2.25.1