[S390] dasd calls kzalloc while holding a spinlock.

The dasd function dasd_set_uid calls kzalloc while holding the
dasd_devmap_lock. Rearrange the code to do the memory allocation
outside the lock.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 28 insertions, 37 deletions

diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index 7f6fdac74706..6fcb28d55a9d 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -89,7 +89,7 @@ static char *dasd[256];
 module_param_array(dasd, charp, NULL, 0);
 
 /*
- * Single spinlock to protect devmap structures and lists.
+ * Single spinlock to protect devmap and servermap structures and lists.
  */
 static DEFINE_SPINLOCK(dasd_devmap_lock);
 
@@ -859,39 +859,6 @@ static struct attribute_group dasd_attr_group = {
 };
 
 /*
- * Check if the related storage server is already contained in the
- * dasd_serverlist. If server is not contained, create new entry.
- * Return 0 if server was already in serverlist,
- *        1 if the server was added successfully
- *       <0 in case of error.
- */
-static int
-dasd_add_server(struct dasd_uid *uid)
-{
-        struct dasd_servermap *new, *tmp;
-
-        /* check if server is already contained */
-        list_for_each_entry(tmp, &dasd_serverlist, list)
-          // normale cmp?
-                if (strncmp(tmp->sid.vendor, uid->vendor,
-                            sizeof(tmp->sid.vendor)) == 0
-                    && strncmp(tmp->sid.serial, uid->serial,
-                               sizeof(tmp->sid.serial)) == 0)
-                        return 0;
-
-        new = (struct dasd_servermap *)
-                kzalloc(sizeof(struct dasd_servermap), GFP_KERNEL);
-        if (!new)
-                return -ENOMEM;
-
-        strncpy(new->sid.vendor, uid->vendor, sizeof(new->sid.vendor));
-        strncpy(new->sid.serial, uid->serial, sizeof(new->sid.serial));
-        list_add(&new->list, &dasd_serverlist);
-        return 1;
-}
-
-
-/*
  * Return copy of the device unique identifier.
  */
 int
@@ -910,6 +877,8 @@ dasd_get_uid(struct ccw_device *cdev, struct dasd_uid *uid)
 
 /*
  * Register the given device unique identifier into devmap struct.
+ * In addition check if the related storage server is already contained in the
+ * dasd_serverlist. If server is not contained, create new entry.
  * Return 0 if server was already in serverlist,
  *        1 if the server was added successful
  *       <0 in case of error.
@@ -918,16 +887,38 @@ int
 dasd_set_uid(struct ccw_device *cdev, struct dasd_uid *uid)
 {
         struct dasd_devmap *devmap;
-        int rc;
+        struct dasd_servermap *srv, *tmp;
 
         devmap = dasd_find_busid(cdev->dev.bus_id);
         if (IS_ERR(devmap))
                 return PTR_ERR(devmap);
+
+        /* generate entry for servermap */
+        srv = (struct dasd_servermap *)
+                kzalloc(sizeof(struct dasd_servermap), GFP_KERNEL);
+        if (!srv)
+                return -ENOMEM;
+        strncpy(srv->sid.vendor, uid->vendor, sizeof(srv->sid.vendor) - 1);
+        strncpy(srv->sid.serial, uid->serial, sizeof(srv->sid.serial) - 1);
+
+        /* server is already contained ? */
         spin_lock(&dasd_devmap_lock);
         devmap->uid = *uid;
-        rc = dasd_add_server(uid);
+        list_for_each_entry(tmp, &dasd_serverlist, list) {
+                if (!memcmp(&srv->sid, &tmp->sid,
+                            sizeof(struct dasd_servermap))) {
+                        kfree(srv);
+                        srv = NULL;
+                        break;
+                }
+        }
+
+        /* add servermap to serverlist */
+        if (srv)
+                list_add(&srv->list, &dasd_serverlist);
         spin_unlock(&dasd_devmap_lock);
-        return rc;
+
+        return (srv ? 1 : 0);
 }
 EXPORT_SYMBOL_GPL(dasd_set_uid);