qdio: Keep device-specific dbf entries

Keep the per-device dbf entries until module is removed, with
proper error checking for debug feature setup.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 72 insertions, 7 deletions

diff --git a/drivers/s390/cio/qdio_debug.c b/drivers/s390/cio/qdio_debug.c
index 4221b02085ad..f1f3baa8e6e4 100644
--- a/drivers/s390/cio/qdio_debug.c
+++ b/drivers/s390/cio/qdio_debug.c
@@ -7,6 +7,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/export.h>
+#include <linux/slab.h>
 #include <asm/debug.h>
 #include "qdio_debug.h"
 #include "qdio.h"
@@ -16,11 +17,51 @@ debug_info_t *qdio_dbf_error;
 
 static struct dentry *debugfs_root;
 #define QDIO_DEBUGFS_NAME_LEN   10
+#define QDIO_DBF_NAME_LEN       20
 
-void qdio_allocate_dbf(struct qdio_initialize *init_data,
+struct qdio_dbf_entry {
+        char dbf_name[QDIO_DBF_NAME_LEN];
+        debug_info_t *dbf_info;
+        struct list_head dbf_list;
+};
+
+static LIST_HEAD(qdio_dbf_list);
+static DEFINE_MUTEX(qdio_dbf_list_mutex);
+
+static debug_info_t *qdio_get_dbf_entry(char *name)
+{
+        struct qdio_dbf_entry *entry;
+        debug_info_t *rc = NULL;
+
+        mutex_lock(&qdio_dbf_list_mutex);
+        list_for_each_entry(entry, &qdio_dbf_list, dbf_list) {
+                if (strcmp(entry->dbf_name, name) == 0) {
+                        rc = entry->dbf_info;
+                        break;
+                }
+        }
+        mutex_unlock(&qdio_dbf_list_mutex);
+        return rc;
+}
+
+static void qdio_clear_dbf_list(void)
+{
+        struct qdio_dbf_entry *entry, *tmp;
+
+        mutex_lock(&qdio_dbf_list_mutex);
+        list_for_each_entry_safe(entry, tmp, &qdio_dbf_list, dbf_list) {
+                list_del(&entry->dbf_list);
+                debug_unregister(entry->dbf_info);
+                kfree(entry);
+        }
+        mutex_unlock(&qdio_dbf_list_mutex);
+}
+
+int qdio_allocate_dbf(struct qdio_initialize *init_data,
                        struct qdio_irq *irq_ptr)
 {
-        char text[20];
+        char text[QDIO_DBF_NAME_LEN];
+        struct qdio_dbf_entry *new_entry;
 
         DBF_EVENT("qfmt:%1d", init_data->q_format);
         DBF_HEX(init_data->adapter_name, 8);
@@ -38,11 +79,34 @@ void qdio_allocate_dbf(struct qdio_initialize *init_data,
         DBF_EVENT("irq:%8lx", (unsigned long)irq_ptr);
 
         /* allocate trace view for the interface */
-        snprintf(text, 20, "qdio_%s", dev_name(&init_data->cdev->dev));
-        irq_ptr->debug_area = debug_register(text, 2, 1, 16);
-        debug_register_view(irq_ptr->debug_area, &debug_hex_ascii_view);
-        debug_set_level(irq_ptr->debug_area, DBF_WARN);
-        DBF_DEV_EVENT(DBF_ERR, irq_ptr, "dbf created");
+        snprintf(text, QDIO_DBF_NAME_LEN, "qdio_%s",
+                                        dev_name(&init_data->cdev->dev));
+        irq_ptr->debug_area = qdio_get_dbf_entry(text);
+        if (irq_ptr->debug_area)
+                DBF_DEV_EVENT(DBF_ERR, irq_ptr, "dbf reused");
+        else {
+                irq_ptr->debug_area = debug_register(text, 2, 1, 16);
+                if (!irq_ptr->debug_area)
+                        return -ENOMEM;
+                if (debug_register_view(irq_ptr->debug_area,
+                                                &debug_hex_ascii_view)) {
+                        debug_unregister(irq_ptr->debug_area);
+                        return -ENOMEM;
+                }
+                debug_set_level(irq_ptr->debug_area, DBF_WARN);
+                DBF_DEV_EVENT(DBF_ERR, irq_ptr, "dbf created");
+                new_entry = kzalloc(sizeof(struct qdio_dbf_entry), GFP_KERNEL);
+                if (!new_entry) {
+                        debug_unregister(irq_ptr->debug_area);
+                        return -ENOMEM;
+                }
+                strlcpy(new_entry->dbf_name, text, QDIO_DBF_NAME_LEN);
+                new_entry->dbf_info = irq_ptr->debug_area;
+                mutex_lock(&qdio_dbf_list_mutex);
+                list_add(&new_entry->dbf_list, &qdio_dbf_list);
+                mutex_unlock(&qdio_dbf_list_mutex);
+        }
+        return 0;
 }
 
 static int qstat_show(struct seq_file *m, void *v)
@@ -300,6 +364,7 @@ int __init qdio_debug_init(void)
 
 void qdio_debug_exit(void)
 {
+        qdio_clear_dbf_list();
         debugfs_remove(debugfs_root);
         if (qdio_dbf_setup)
                 debug_unregister(qdio_dbf_setup);