x86/intel_rdt: Add diagnostics when making directories

Mostly this is about running out of RMIDs or CLOSIDs. Other
errors are various internal errors.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/027cf1ffb3a3695f2d54525813a1d644887353cf.1506382469.git.tony.luck@intel.com

1 files changed, 22 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 6e0ee7ca1490..abd220bf6cd7 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1593,8 +1593,10 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
         int ret;
 
         prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
+        rdt_last_cmd_clear();
         if (!prdtgrp) {
                 ret = -ENODEV;
+                rdt_last_cmd_puts("directory was removed\n");
                 goto out_unlock;
         }
 
@@ -1602,6 +1604,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
         rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
         if (!rdtgrp) {
                 ret = -ENOSPC;
+                rdt_last_cmd_puts("kernel out of memory\n");
                 goto out_unlock;
         }
         *r = rdtgrp;
@@ -1613,6 +1616,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
         kn = kernfs_create_dir(parent_kn, name, mode, rdtgrp);
         if (IS_ERR(kn)) {
                 ret = PTR_ERR(kn);
+                rdt_last_cmd_puts("kernfs create error\n");
                 goto out_free_rgrp;
         }
         rdtgrp->kn = kn;
@@ -1626,24 +1630,32 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
         kernfs_get(kn);
 
         ret = rdtgroup_kn_set_ugid(kn);
-        if (ret)
+        if (ret) {
+                rdt_last_cmd_puts("kernfs perm error\n");
                 goto out_destroy;
+        }
 
         files = RFTYPE_BASE | RFTYPE_CTRL;
         files = RFTYPE_BASE | BIT(RF_CTRLSHIFT + rtype);
         ret = rdtgroup_add_files(kn, files);
-        if (ret)
+        if (ret) {
+                rdt_last_cmd_puts("kernfs fill error\n");
                 goto out_destroy;
+        }
 
         if (rdt_mon_capable) {
                 ret = alloc_rmid();
-                if (ret < 0)
+                if (ret < 0) {
+                        rdt_last_cmd_puts("out of RMIDs\n");
                         goto out_destroy;
+                }
                 rdtgrp->mon.rmid = ret;
 
                 ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
-                if (ret)
+                if (ret) {
+                        rdt_last_cmd_puts("kernfs subdir error\n");
                         goto out_idfree;
+                }
         }
         kernfs_activate(kn);
 
@@ -1721,8 +1733,10 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 
         kn = rdtgrp->kn;
         ret = closid_alloc();
-        if (ret < 0)
+        if (ret < 0) {
+                rdt_last_cmd_puts("out of CLOSIDs\n");
                 goto out_common_fail;
+        }
         closid = ret;
 
         rdtgrp->closid = closid;
@@ -1734,8 +1748,10 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
                  * of tasks and cpus to monitor.
                  */
                 ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL);
-                if (ret)
+                if (ret) {
+                        rdt_last_cmd_puts("kernfs subdir error\n");
                         goto out_id_free;
+                }
         }
 
         goto out_unlock;