[PATCH] s390: z/VM monitor stream.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix for z/VM monitor stream:
 - Add try_module_get and module_put to the [un]register functions.
 - Some code beautification.

diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c
index 377f78e7c9fa3e513d2ab6e77b4d1dbd5af66b8a..6f9ab94bf1fda94e63eaec7f5eb40971ee8a02ae 100644 (file)
--- a/arch/s390/appldata/appldata_base.c
+++ b/arch/s390/appldata/appldata_base.c
@@ -233,8 +233,8 @@ static int appldata_diag(char record_nr, u16 function, unsigned long buffer,
                                .buffer_addr = virt_to_phys((void *) buffer)
        };
 
-        if (!MACHINE_IS_VM)
-                return -ENOSYS;
+       if (!MACHINE_IS_VM)
+               return -ENOSYS;
        ry = -1;
        asm volatile(
                        "diag %1,%0,0xDC\n\t"
@@ -336,9 +336,9 @@ appldata_interval_handler(ctl_table *ctl, int write, struct file *filp,
                P_ERROR("Timer CPU interval has to be > 0!\n");
                return -EINVAL;
        }
-       per_cpu_interval = (u64) (interval*1000 / num_online_cpus()) * TOD_MICRO;
 
        spin_lock(&appldata_timer_lock);
+       per_cpu_interval = (u64) (interval*1000 / num_online_cpus()) * TOD_MICRO;
        appldata_interval = interval;
        if (appldata_timer_active) {
                for (i = 0; i < num_online_cpus(); i++) {
@@ -395,6 +395,10 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
 
        spin_lock_bh(&appldata_ops_lock);
        if ((buf[0] == '1') && (ops->active == 0)) {
+               if (!try_module_get(ops->owner)) {
+                       spin_unlock_bh(&appldata_ops_lock);
+                       return -ENODEV;
+               }
                ops->active = 1;
                ops->callback(ops->data);       // init record
                rc = appldata_diag(ops->record_nr,
@@ -403,6 +407,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
                if (rc != 0) {
                        P_ERROR("START DIAG 0xDC for %s failed, "
                                "return code: %d\n", ops->name, rc);
+                       module_put(ops->owner);
                        ops->active = 0;
                } else {
                        P_INFO("Monitoring %s data enabled, "
@@ -419,6 +424,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp,
                        P_INFO("Monitoring %s data disabled, "
                                "DIAG 0xDC stopped.\n", ops->name);
                }
+               module_put(ops->owner);
        }
        spin_unlock_bh(&appldata_ops_lock);
 out:
@@ -440,30 +446,26 @@ int appldata_register_ops(struct appldata_ops *ops)
 {
        struct list_head *lh;
        struct appldata_ops *tmp_ops;
-       int rc, i;
+       int i;
 
-       rc = 0;
        i = 0;
 
        if ((ops->size > APPLDATA_MAX_REC_SIZE) ||
                (ops->size < 0)){
                P_ERROR("Invalid size of %s record = %i, maximum = %i!\n",
                        ops->name, ops->size, APPLDATA_MAX_REC_SIZE);
-               rc = -ENOMEM;
-               goto out;
+               return -ENOMEM;
        }
        if ((ops->ctl_nr == CTL_APPLDATA) ||
            (ops->ctl_nr == CTL_APPLDATA_TIMER) ||
            (ops->ctl_nr == CTL_APPLDATA_INTERVAL)) {
                P_ERROR("ctl_nr %i already in use!\n", ops->ctl_nr);
-               rc = -EBUSY;
-               goto out;
+               return -EBUSY;
        }
        ops->ctl_table = kmalloc(4*sizeof(struct ctl_table), GFP_KERNEL);
        if (ops->ctl_table == NULL) {
                P_ERROR("Not enough memory for %s ctl_table!\n", ops->name);
-               rc = -ENOMEM;
-               goto out;
+               return -ENOMEM;
        }
        memset(ops->ctl_table, 0, 4*sizeof(struct ctl_table));
 
@@ -477,18 +479,16 @@ int appldata_register_ops(struct appldata_ops *ops)
                        ops->ctl_nr);
                if (strncmp(tmp_ops->name, ops->name,
                                APPLDATA_PROC_NAME_LENGTH) == 0) {
-                       spin_unlock_bh(&appldata_ops_lock);
                        P_ERROR("Name \"%s\" already registered!\n", ops->name);
                        kfree(ops->ctl_table);
-                       rc = -EBUSY;
-                       goto out;
+                       spin_unlock_bh(&appldata_ops_lock);
+                       return -EBUSY;
                }
                if (tmp_ops->ctl_nr == ops->ctl_nr) {
-                       spin_unlock_bh(&appldata_ops_lock);
                        P_ERROR("ctl_nr %i already registered!\n", ops->ctl_nr);
                        kfree(ops->ctl_table);
-                       rc = -EBUSY;
-                       goto out;
+                       spin_unlock_bh(&appldata_ops_lock);
+                       return -EBUSY;
                }
        }
        list_add(&ops->list, &appldata_ops_list);
@@ -512,9 +512,9 @@ int appldata_register_ops(struct appldata_ops *ops)
 
        ops->sysctl_header = register_sysctl_table(ops->ctl_table,1);
        ops->ctl_table[2].de->owner = ops->owner;
+
        P_INFO("%s-ops registered!\n", ops->name);
-out:
-       return rc;
+       return 0;
 }
 
 /*
@@ -524,26 +524,11 @@ out:
  */
 void appldata_unregister_ops(struct appldata_ops *ops)
 {
-       int rc;
-
-       unregister_sysctl_table(ops->sysctl_header);
-       kfree(ops->ctl_table);
-       if (ops->active == 1) {
-               ops->active = 0;
-               rc = appldata_diag(ops->record_nr, APPLDATA_STOP_REC,
-                               (unsigned long) ops->data, ops->size);
-               if (rc != 0) {
-                       P_ERROR("STOP DIAG 0xDC for %s failed, "
-                               "return code: %d\n", ops->name, rc);
-               } else {
-                       P_INFO("Monitoring %s data disabled, "
-                               "DIAG 0xDC stopped.\n", ops->name);
-               }
-
-       }
        spin_lock_bh(&appldata_ops_lock);
        list_del(&ops->list);
        spin_unlock_bh(&appldata_ops_lock);
+       unregister_sysctl_table(ops->sysctl_header);
+       kfree(ops->ctl_table);
        P_INFO("%s-ops unregistered!\n", ops->name);
 }
 /********************** module-ops management <END> **************************/