ccwgroup: Unify parsing for group attribute.

Instead of having each driver for ccwgroup slave device parsing the
input itself and calling ccwgroup_create(), introduce a new function
ccwgroup_create_from_string() and handle parsing inside the ccwgroup
core.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

3 files changed, 79 insertions, 60 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 03914fa81174..f38923e38e92 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -153,44 +153,89 @@ __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
         return 0;
 }
 
+static int __get_next_bus_id(const char **buf, char *bus_id)
+{
+        int rc, len;
+        char *start, *end;
+
+        start = (char *)*buf;
+        end = strchr(start, ',');
+        if (!end) {
+                /* Last entry. Strip trailing newline, if applicable. */
+                end = strchr(start, '\n');
+                if (end)
+                        *end = '\0';
+                len = strlen(start) + 1;
+        } else {
+                len = end - start + 1;
+                end++;
+        }
+        if (len < BUS_ID_SIZE) {
+                strlcpy(bus_id, start, len);
+                rc = 0;
+        } else
+                rc = -EINVAL;
+        *buf = end;
+        return rc;
+}
+
+static int __is_valid_bus_id(char bus_id[BUS_ID_SIZE])
+{
+        int cssid, ssid, devno;
+
+        /* Must be of form %x.%x.%04x */
+        if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
+                return 0;
+        return 1;
+}
+
 /**
- * ccwgroup_create() - create and register a ccw group device
+ * ccwgroup_create_from_string() - create and register a ccw group device
  * @root: parent device for the new device
  * @creator_id: identifier of creating driver
  * @cdrv: ccw driver of slave devices
- * @argc: number of slave devices
- * @argv: bus ids of slave devices
+ * @num_devices: number of slave devices
+ * @buf: buffer containing comma separated bus ids of slave devices
  *
  * Create and register a new ccw group device as a child of @root. Slave
- * devices are obtained from the list of bus ids given in @argv[] and must all
+ * devices are obtained from the list of bus ids given in @buf and must all
  * belong to @cdrv.
  * Returns:
  *  %0 on success and an error code on failure.
  * Context:
  *  non-atomic
  */
-int ccwgroup_create(struct device *root, unsigned int creator_id,
-                    struct ccw_driver *cdrv, int argc, char *argv[])
+int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
+                                struct ccw_driver *cdrv, int num_devices,
+                                const char *buf)
 {
         struct ccwgroup_device *gdev;
-        int i;
-        int rc;
+        int rc, i;
+        char tmp_bus_id[BUS_ID_SIZE];
+        const char *curr_buf;
 
-        if (argc > 256) /* disallow dumb users */
-                return -EINVAL;
-
-        gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
+        gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
+                       GFP_KERNEL);
         if (!gdev)
                 return -ENOMEM;
 
         atomic_set(&gdev->onoff, 0);
         mutex_init(&gdev->reg_mutex);
         mutex_lock(&gdev->reg_mutex);
-        for (i = 0; i < argc; i++) {
-                gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
-
-                /* all devices have to be of the same type in
-                 * order to be grouped */
+        curr_buf = buf;
+        for (i = 0; i < num_devices && curr_buf; i++) {
+                rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
+                if (rc != 0)
+                        goto error;
+                if (!__is_valid_bus_id(tmp_bus_id)) {
+                        rc = -EINVAL;
+                        goto error;
+                }
+                gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
+                /*
+                 * All devices have to be of the same type in
+                 * order to be grouped.
+                 */
                 if (!gdev->cdev[i]
                     || gdev->cdev[i]->id.driver_info !=
                     gdev->cdev[0]->id.driver_info) {
@@ -204,9 +249,18 @@ int ccwgroup_create(struct device *root, unsigned int creator_id,
                 }
                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
         }
-
+        /* Check for sufficient number of bus ids. */
+        if (i < num_devices && !curr_buf) {
+                rc = -EINVAL;
+                goto error;
+        }
+        /* Check for trailing stuff. */
+        if (i == num_devices && strlen(curr_buf) > 0) {
+                rc = -EINVAL;
+                goto error;
+        }
         gdev->creator_id = creator_id;
-        gdev->count = argc;
+        gdev->count = num_devices;
         gdev->dev.bus = &ccwgroup_bus_type;
         gdev->dev.parent = root;
         gdev->dev.release = ccwgroup_release;
@@ -234,7 +288,7 @@ int ccwgroup_create(struct device *root, unsigned int creator_id,
         device_remove_file(&gdev->dev, &dev_attr_ungroup);
         device_unregister(&gdev->dev);
 error:
-        for (i = 0; i < argc; i++)
+        for (i = 0; i < num_devices; i++)
                 if (gdev->cdev[i]) {
                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
@@ -244,6 +298,7 @@ error:
         put_device(&gdev->dev);
         return rc;
 }
+EXPORT_SYMBOL(ccwgroup_create_from_string);
 
 static int __init
 init_ccwgroup (void)
@@ -519,6 +574,5 @@ void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 MODULE_LICENSE("GPL");
 EXPORT_SYMBOL(ccwgroup_driver_register);
 EXPORT_SYMBOL(ccwgroup_driver_unregister);
-EXPORT_SYMBOL(ccwgroup_create);
 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
diff --git a/drivers/s390/net/cu3088.c b/drivers/s390/net/cu3088.c
index 76728ae4b843..8e7697305a4c 100644
--- a/drivers/s390/net/cu3088.c
+++ b/drivers/s390/net/cu3088.c
@@ -62,30 +62,14 @@ static struct device *cu3088_root_dev;
 static ssize_t
 group_write(struct device_driver *drv, const char *buf, size_t count)
 {
-        const char *start, *end;
-        char bus_ids[2][BUS_ID_SIZE], *argv[2];
-        int i;
         int ret;
         struct ccwgroup_driver *cdrv;
 
         cdrv = to_ccwgroupdrv(drv);
         if (!cdrv)
                 return -EINVAL;
-        start = buf;
-        for (i=0; i<2; i++) {
-                static const char delim[] = {',', '\n'};
-                int len;
-
-                if (!(end = strchr(start, delim[i])))
-                        return -EINVAL;
-                len = min_t(ptrdiff_t, BUS_ID_SIZE, end - start + 1);
-                strlcpy (bus_ids[i], start, len);
-                argv[i] = bus_ids[i];
-                start = end + 1;
-        }
-
-        ret = ccwgroup_create(cu3088_root_dev, cdrv->driver_id,
-                              &cu3088_driver, 2, argv);
+        ret = ccwgroup_create_from_string(cu3088_root_dev, cdrv->driver_id,
+                                          &cu3088_driver, 2, buf);
 
         return (ret == 0) ? count : ret;
 }
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 055f5c3e7b56..231d18c3b6f7 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -3827,27 +3827,8 @@ static struct ccw_driver qeth_ccw_driver = {
 static int qeth_core_driver_group(const char *buf, struct device *root_dev,
                                 unsigned long driver_id)
 {
-        const char *start, *end;
-        char bus_ids[3][BUS_ID_SIZE], *argv[3];
-        int i;
-
-        start = buf;
-        for (i = 0; i < 3; i++) {
-                static const char delim[] = { ',', ',', '\n' };
-                int len;
-
-                end = strchr(start, delim[i]);
-                if (!end)
-                        return -EINVAL;
-                len = min_t(ptrdiff_t, BUS_ID_SIZE, end - start);
-                strncpy(bus_ids[i], start, len);
-                bus_ids[i][len] = '\0';
-                start = end + 1;
-                argv[i] = bus_ids[i];
-        }
-
-        return (ccwgroup_create(root_dev, driver_id,
-                                &qeth_ccw_driver, 3, argv));
+        return ccwgroup_create_from_string(root_dev, driver_id,
+                                           &qeth_ccw_driver, 3, buf);
 }
 
 int qeth_core_hardsetup_card(struct qeth_card *card)