cxl: Change 'struct cxl_memdev_state' *_perf_list to single 'struct cxl_dpa_perf'

In order to address the issue with being able to expose qos_class sysfs
attributes under 'ram' and 'pmem' sub-directories, the attributes must
be defined as static attributes rather than under driver->dev_groups.
To avoid implementing locking for accessing the 'struct cxl_dpa_perf`
lists, convert the list to a single 'struct cxl_dpa_perf' entry in
preparation to move the attributes to statically defined.

While theoretically a partition may have multiple qos_class via CDAT, this
has not been encountered with testing on available hardware. The code is
simplified for now to not support the complex case until a use case is
needed to support that.

Link: https://lore.kernel.org/linux-cxl/65b200ba228f_2d43c29468@dwillia2-mobl3.amr.corp.intel.com.notmuch/
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20240206190431.1810289-2-dave.jiang@intel.com
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
index 6fe11546889fabb48e997fda83e1f184a64179c6..d66acc917dac3104be9bfe1dccf72c17f96e9871 100644 (file)
--- a/drivers/cxl/core/cdat.c
+++ b/drivers/cxl/core/cdat.c
@@ -210,19 +210,12 @@ static int cxl_port_perf_data_calculate(struct cxl_port *port,
        return 0;
 }
 
-static void add_perf_entry(struct device *dev, struct dsmas_entry *dent,
-                          struct list_head *list)
+static void update_perf_entry(struct device *dev, struct dsmas_entry *dent,
+                             struct cxl_dpa_perf *dpa_perf)
 {
-       struct cxl_dpa_perf *dpa_perf;
-
-       dpa_perf = kzalloc(sizeof(*dpa_perf), GFP_KERNEL);
-       if (!dpa_perf)
-               return;
-
        dpa_perf->dpa_range = dent->dpa_range;
        dpa_perf->coord = dent->coord;
        dpa_perf->qos_class = dent->qos_class;
-       list_add_tail(&dpa_perf->list, list);
        dev_dbg(dev,
                "DSMAS: dpa: %#llx qos: %d read_bw: %d write_bw %d read_lat: %d write_lat: %d\n",
                dent->dpa_range.start, dpa_perf->qos_class,
@@ -230,20 +223,6 @@ static void add_perf_entry(struct device *dev, struct dsmas_entry *dent,
                dent->coord.read_latency, dent->coord.write_latency);
 }
 
-static void free_perf_ents(void *data)
-{
-       struct cxl_memdev_state *mds = data;
-       struct cxl_dpa_perf *dpa_perf, *n;
-       LIST_HEAD(discard);
-
-       list_splice_tail_init(&mds->ram_perf_list, &discard);
-       list_splice_tail_init(&mds->pmem_perf_list, &discard);
-       list_for_each_entry_safe(dpa_perf, n, &discard, list) {
-               list_del(&dpa_perf->list);
-               kfree(dpa_perf);
-       }
-}
-
 static void cxl_memdev_set_qos_class(struct cxl_dev_state *cxlds,
                                     struct xarray *dsmas_xa)
 {
@@ -263,16 +242,14 @@ static void cxl_memdev_set_qos_class(struct cxl_dev_state *cxlds,
        xa_for_each(dsmas_xa, index, dent) {
                if (resource_size(&cxlds->ram_res) &&
                    range_contains(&ram_range, &dent->dpa_range))
-                       add_perf_entry(dev, dent, &mds->ram_perf_list);
+                       update_perf_entry(dev, dent, &mds->ram_perf);
                else if (resource_size(&cxlds->pmem_res) &&
                         range_contains(&pmem_range, &dent->dpa_range))
-                       add_perf_entry(dev, dent, &mds->pmem_perf_list);
+                       update_perf_entry(dev, dent, &mds->pmem_perf);
                else
                        dev_dbg(dev, "no partition for dsmas dpa: %#llx\n",
                                dent->dpa_range.start);
        }
-
-       devm_add_action_or_reset(&cxlds->cxlmd->dev, free_perf_ents, mds);
 }
 
 static int match_cxlrd_qos_class(struct device *dev, void *data)
@@ -293,24 +270,24 @@ static int match_cxlrd_qos_class(struct device *dev, void *data)
        return 0;
 }
 
-static void cxl_qos_match(struct cxl_port *root_port,
-                         struct list_head *work_list,
-                         struct list_head *discard_list)
+static void reset_dpa_perf(struct cxl_dpa_perf *dpa_perf)
 {
-       struct cxl_dpa_perf *dpa_perf, *n;
+       *dpa_perf = (struct cxl_dpa_perf) {
+               .qos_class = CXL_QOS_CLASS_INVALID,
+       };
+}
 
-       list_for_each_entry_safe(dpa_perf, n, work_list, list) {
-               int rc;
+static bool cxl_qos_match(struct cxl_port *root_port,
+                         struct cxl_dpa_perf *dpa_perf)
+{
+       if (dpa_perf->qos_class == CXL_QOS_CLASS_INVALID)
+               return false;
 
-               if (dpa_perf->qos_class == CXL_QOS_CLASS_INVALID)
-                       return;
+       if (!device_for_each_child(&root_port->dev, &dpa_perf->qos_class,
+                                  match_cxlrd_qos_class))
+               return false;
 
-               rc = device_for_each_child(&root_port->dev,
-                                          (void *)&dpa_perf->qos_class,
-                                          match_cxlrd_qos_class);
-               if (!rc)
-                       list_move_tail(&dpa_perf->list, discard_list);
-       }
+       return true;
 }
 
 static int match_cxlrd_hb(struct device *dev, void *data)
@@ -334,23 +311,10 @@ static int match_cxlrd_hb(struct device *dev, void *data)
        return 0;
 }
 
-static void discard_dpa_perf(struct list_head *list)
-{
-       struct cxl_dpa_perf *dpa_perf, *n;
-
-       list_for_each_entry_safe(dpa_perf, n, list, list) {
-               list_del(&dpa_perf->list);
-               kfree(dpa_perf);
-       }
-}
-DEFINE_FREE(dpa_perf, struct list_head *, if (!list_empty(_T)) discard_dpa_perf(_T))
-
 static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
 {
        struct cxl_dev_state *cxlds = cxlmd->cxlds;
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-       LIST_HEAD(__discard);
-       struct list_head *discard __free(dpa_perf) = &__discard;
        struct cxl_port *root_port;
        int rc;
 
@@ -363,16 +327,18 @@ static int cxl_qos_class_verify(struct cxl_memdev *cxlmd)
        root_port = &cxl_root->port;
 
        /* Check that the QTG IDs are all sane between end device and root decoders */
-       cxl_qos_match(root_port, &mds->ram_perf_list, discard);
-       cxl_qos_match(root_port, &mds->pmem_perf_list, discard);
+       if (!cxl_qos_match(root_port, &mds->ram_perf))
+               reset_dpa_perf(&mds->ram_perf);
+       if (!cxl_qos_match(root_port, &mds->pmem_perf))
+               reset_dpa_perf(&mds->pmem_perf);
 
        /* Check to make sure that the device's host bridge is under a root decoder */
        rc = device_for_each_child(&root_port->dev,
                                   (void *)cxlmd->endpoint->host_bridge,
                                   match_cxlrd_hb);
        if (!rc) {
-               list_splice_tail_init(&mds->ram_perf_list, discard);
-               list_splice_tail_init(&mds->pmem_perf_list, discard);
+               reset_dpa_perf(&mds->ram_perf);
+               reset_dpa_perf(&mds->pmem_perf);
        }
 
        return rc;

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 27166a41170579a9441a2f9bf3e2a915ed85d893..9adda4795eb786b8658b573dd1e79befbad52255 100644 (file)
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1391,8 +1391,8 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
        mds->cxlds.reg_map.host = dev;
        mds->cxlds.reg_map.resource = CXL_RESOURCE_NONE;
        mds->cxlds.type = CXL_DEVTYPE_CLASSMEM;
-       INIT_LIST_HEAD(&mds->ram_perf_list);
-       INIT_LIST_HEAD(&mds->pmem_perf_list);
+       mds->ram_perf.qos_class = CXL_QOS_CLASS_INVALID;
+       mds->pmem_perf.qos_class = CXL_QOS_CLASS_INVALID;
 
        return mds;
 }

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 5303d6942b880af65dcf8e77b02d26626c2bb94d..20fb3b35e89e0473ee8ad42dcd17407086fb8cdb 100644 (file)
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -395,13 +395,11 @@ enum cxl_devtype {
 
 /**
  * struct cxl_dpa_perf - DPA performance property entry
- * @list - list entry
  * @dpa_range - range for DPA address
  * @coord - QoS performance data (i.e. latency, bandwidth)
  * @qos_class - QoS Class cookies
  */
 struct cxl_dpa_perf {
-       struct list_head list;
        struct range dpa_range;
        struct access_coordinate coord;
        int qos_class;
@@ -471,8 +469,8 @@ struct cxl_dev_state {
  * @security: security driver state info
  * @fw: firmware upload / activation state
  * @mbox_send: @dev specific transport for transmitting mailbox commands
- * @ram_perf_list: performance data entries matched to RAM
- * @pmem_perf_list: performance data entries matched to PMEM
+ * @ram_perf: performance data entry matched to RAM partition
+ * @pmem_perf: performance data entry matched to PMEM partition
  *
  * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
  * details on capacity parameters.
@@ -494,8 +492,8 @@ struct cxl_memdev_state {
        u64 next_volatile_bytes;
        u64 next_persistent_bytes;
 
-       struct list_head ram_perf_list;
-       struct list_head pmem_perf_list;
+       struct cxl_dpa_perf ram_perf;
+       struct cxl_dpa_perf pmem_perf;
 
        struct cxl_event_state event;
        struct cxl_poison_state poison;

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index c5c9d8e0d88d69fcc9f031e1bd46ba7c44de4fd4..547f5a145fc5408f09acaf1fda37c4cd3e7914e9 100644 (file)
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -221,18 +221,8 @@ static ssize_t ram_qos_class_show(struct device *dev,
        struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
        struct cxl_dev_state *cxlds = cxlmd->cxlds;
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-       struct cxl_dpa_perf *dpa_perf;
 
-       if (!dev->driver)
-               return -ENOENT;
-
-       if (list_empty(&mds->ram_perf_list))
-               return -ENOENT;
-
-       dpa_perf = list_first_entry(&mds->ram_perf_list, struct cxl_dpa_perf,
-                                   list);
-
-       return sysfs_emit(buf, "%d\n", dpa_perf->qos_class);
+       return sysfs_emit(buf, "%d\n", mds->ram_perf.qos_class);
 }
 
 static struct device_attribute dev_attr_ram_qos_class =
@@ -244,18 +234,8 @@ static ssize_t pmem_qos_class_show(struct device *dev,
        struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
        struct cxl_dev_state *cxlds = cxlmd->cxlds;
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
-       struct cxl_dpa_perf *dpa_perf;
-
-       if (!dev->driver)
-               return -ENOENT;
-
-       if (list_empty(&mds->pmem_perf_list))
-               return -ENOENT;
-
-       dpa_perf = list_first_entry(&mds->pmem_perf_list, struct cxl_dpa_perf,
-                                   list);
 
-       return sysfs_emit(buf, "%d\n", dpa_perf->qos_class);
+       return sysfs_emit(buf, "%d\n", mds->pmem_perf.qos_class);
 }
 
 static struct device_attribute dev_attr_pmem_qos_class =
@@ -273,11 +253,11 @@ static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
                        return 0;
 
        if (a == &dev_attr_pmem_qos_class.attr)
-               if (list_empty(&mds->pmem_perf_list))
+               if (mds->pmem_perf.qos_class == CXL_QOS_CLASS_INVALID)
                        return 0;
 
        if (a == &dev_attr_ram_qos_class.attr)
-               if (list_empty(&mds->ram_perf_list))
+               if (mds->ram_perf.qos_class == CXL_QOS_CLASS_INVALID)
                        return 0;
 
        return a->mode;