nvme: refactor the atomic write unit detection

Move all the code out of nvme_update_disk_info into the helper, and
rename the helper to have a somewhat less clumsy name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 724f5732786c071b5a87e6a7773f859e0f64ffbc..520fb5f1e2147b1079cea2e3cfe2360040ac7798 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2015,21 +2015,51 @@ static void nvme_configure_metadata(struct nvme_ctrl *ctrl,
 }
 
 
-static void nvme_update_atomic_write_disk_info(struct nvme_ns *ns,
-                       struct nvme_id_ns *id, struct queue_limits *lim,
-                       u32 bs, u32 atomic_bs)
+static u32 nvme_configure_atomic_write(struct nvme_ns *ns,
+               struct nvme_id_ns *id, struct queue_limits *lim, u32 bs)
 {
-       unsigned int boundary = 0;
+       u32 atomic_bs, boundary = 0;
 
-       if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf) {
-               if (le16_to_cpu(id->nabspf))
+       /*
+        * We do not support an offset for the atomic boundaries.
+        */
+       if (id->nabo)
+               return bs;
+
+       if ((id->nsfeat & NVME_NS_FEAT_ATOMICS) && id->nawupf) {
+               /*
+                * Use the per-namespace atomic write unit when available.
+                */
+               atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs;
+               if (id->nabspf)
                        boundary = (le16_to_cpu(id->nabspf) + 1) * bs;
+       } else {
+               /*
+                * Use the controller wide atomic write unit.  This sucks
+                * because the limit is defined in terms of logical blocks while
+                * namespaces can have different formats, and because there is
+                * no clear language in the specification prohibiting different
+                * values for different controllers in the subsystem.
+                */
+               atomic_bs = (1 + ns->ctrl->awupf) * bs;
+       }
+
+       if (!ns->ctrl->subsys->atomic_bs) {
+               ns->ctrl->subsys->atomic_bs = atomic_bs;
+       } else if (ns->ctrl->subsys->atomic_bs != atomic_bs) {
+               dev_err_ratelimited(ns->ctrl->device,
+                       "%s: Inconsistent Atomic Write Size, Namespace will not be added: Subsystem=%d bytes, Controller/Namespace=%d bytes\n",
+                       ns->disk ? ns->disk->disk_name : "?",
+                       ns->ctrl->subsys->atomic_bs,
+                       atomic_bs);
        }
+
        lim->atomic_write_hw_max = atomic_bs;
        lim->atomic_write_hw_boundary = boundary;
        lim->atomic_write_hw_unit_min = bs;
        lim->atomic_write_hw_unit_max = rounddown_pow_of_two(atomic_bs);
        lim->features |= BLK_FEAT_ATOMIC_WRITES;
+       return atomic_bs;
 }
 
 static u32 nvme_max_drv_segments(struct nvme_ctrl *ctrl)
@@ -2067,34 +2097,8 @@ static bool nvme_update_disk_info(struct nvme_ns *ns, struct nvme_id_ns *id,
                valid = false;
        }
 
-       atomic_bs = phys_bs = bs;
-       if (id->nabo == 0) {
-               /*
-                * Bit 1 indicates whether NAWUPF is defined for this namespace
-                * and whether it should be used instead of AWUPF. If NAWUPF ==
-                * 0 then AWUPF must be used instead.
-                */
-               if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf)
-                       atomic_bs = (1 + le16_to_cpu(id->nawupf)) * bs;
-               else
-                       atomic_bs = (1 + ns->ctrl->awupf) * bs;
-
-               /*
-                * Set subsystem atomic bs.
-                */
-               if (ns->ctrl->subsys->atomic_bs) {
-                       if (atomic_bs != ns->ctrl->subsys->atomic_bs) {
-                               dev_err_ratelimited(ns->ctrl->device,
-                                       "%s: Inconsistent Atomic Write Size, Namespace will not be added: Subsystem=%d bytes, Controller/Namespace=%d bytes\n",
-                                       ns->disk ? ns->disk->disk_name : "?",
-                                       ns->ctrl->subsys->atomic_bs,
-                                       atomic_bs);
-                       }
-               } else
-                       ns->ctrl->subsys->atomic_bs = atomic_bs;
-
-               nvme_update_atomic_write_disk_info(ns, id, lim, bs, atomic_bs);
-       }
+       phys_bs = bs;
+       atomic_bs = nvme_configure_atomic_write(ns, id, lim, bs);
 
        if (id->nsfeat & NVME_NS_FEAT_IO_OPT) {
                /* NPWG = Namespace Preferred Write Granularity */