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Subject[PATCH]: HVCS char driver janitoring: fix compile warnings
From


This is a non-urgent patch.

I can't figure out who the upstream maintainer for char drivers
is supposed to be. Can this patch be applied?

--linas

This patch removes an pair of irritating compiler warnings:

drivers/char/hvcs.c:1605: warning: ignoring return value of
sysfs_create_group declared with attribute warn_unused_result
drivers/char/hvcs.c:1639: warning: ignoring return value of
driver_create_file declared with attribute warn_unused_result

Doing this required moving a big block of code from the bottom
of the file to the top, so as to avoid the need for (irritating)
forward declarations.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: Ryan S. Arnold <rsa@us.ibm.com>

----
drivers/char/hvcs.c | 426 +++++++++++++++++++++++++---------------------------
1 file changed, 210 insertions(+), 216 deletions(-)

Index: linux-2.6.19-rc4-git3/drivers/char/hvcs.c
===================================================================
--- linux-2.6.19-rc4-git3.orig/drivers/char/hvcs.c 2006-11-01 16:15:14.000000000 -0600
+++ linux-2.6.19-rc4-git3/drivers/char/hvcs.c 2006-11-15 15:04:50.000000000 -0600
@@ -337,11 +337,6 @@ static int hvcs_open(struct tty_struct *
static void hvcs_close(struct tty_struct *tty, struct file *filp);
static void hvcs_hangup(struct tty_struct * tty);

-static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd);
-static void hvcs_remove_device_attrs(struct vio_dev *vdev);
-static void hvcs_create_driver_attrs(void);
-static void hvcs_remove_driver_attrs(void);
-
static int __devinit hvcs_probe(struct vio_dev *dev,
const struct vio_device_id *id);
static int __devexit hvcs_remove(struct vio_dev *dev);
@@ -353,6 +348,172 @@ static void __exit hvcs_module_exit(void
#define HVCS_TRY_WRITE 0x00000004
#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)

+static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
+{
+ return viod->dev.driver_data;
+}
+/* The sysfs interface for the driver and devices */
+
+static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+ int retval;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+ retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return retval;
+}
+static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
+
+static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+ int retval;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+ retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return retval;
+}
+static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
+
+static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
+ size_t count)
+{
+ /*
+ * Don't need this feature at the present time because firmware doesn't
+ * yet support multiple partners.
+ */
+ printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
+ return -EPERM;
+}
+
+static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+ int retval;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+ retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return retval;
+}
+
+static DEVICE_ATTR(current_vty,
+ S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
+
+static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+
+ /* writing a '0' to this sysfs entry will result in the disconnect. */
+ if (simple_strtol(buf, NULL, 0) != 0)
+ return -EINVAL;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+
+ if (hvcsd->open_count > 0) {
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ printk(KERN_INFO "HVCS: vterm state unchanged. "
+ "The hvcs device node is still in use.\n");
+ return -EPERM;
+ }
+
+ if (hvcsd->connected == 0) {
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ printk(KERN_INFO "HVCS: vterm state unchanged. The"
+ " vty-server is not connected to a vty.\n");
+ return -EPERM;
+ }
+
+ hvcs_partner_free(hvcsd);
+ printk(KERN_INFO "HVCS: Closed vty-server@%X and"
+ " partner vty@%X:%d connection.\n",
+ hvcsd->vdev->unit_address,
+ hvcsd->p_unit_address,
+ (uint32_t)hvcsd->p_partition_ID);
+
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return count;
+}
+
+static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+ int retval;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+ retval = sprintf(buf, "%d\n", hvcsd->connected);
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return retval;
+}
+static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
+ hvcs_vterm_state_show, hvcs_vterm_state_store);
+
+static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct vio_dev *viod = to_vio_dev(dev);
+ struct hvcs_struct *hvcsd = from_vio_dev(viod);
+ unsigned long flags;
+ int retval;
+
+ spin_lock_irqsave(&hvcsd->lock, flags);
+ retval = sprintf(buf, "%d\n", hvcsd->index);
+ spin_unlock_irqrestore(&hvcsd->lock, flags);
+ return retval;
+}
+
+static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
+
+static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
+{
+ /* A 1 means it is updating, a 0 means it is done updating */
+ return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
+}
+
+static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
+ size_t count)
+{
+ if ((simple_strtol(buf, NULL, 0) != 1)
+ && (hvcs_rescan_status != 0))
+ return -EINVAL;
+
+ hvcs_rescan_status = 1;
+ printk(KERN_INFO "HVCS: rescanning partner info for all"
+ " vty-servers.\n");
+ hvcs_rescan_devices_list();
+ hvcs_rescan_status = 0;
+ return count;
+}
+
+static DRIVER_ATTR(rescan,
+ S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
+
+static struct attribute *hvcs_attrs[] = {
+ &dev_attr_partner_vtys.attr,
+ &dev_attr_partner_clcs.attr,
+ &dev_attr_current_vty.attr,
+ &dev_attr_vterm_state.attr,
+ &dev_attr_index.attr,
+ NULL,
+};
+
+static struct attribute_group hvcs_attr_group = {
+ .attrs = hvcs_attrs,
+};
+
static void hvcs_kick(void)
{
hvcs_kicked = 1;
@@ -575,7 +736,7 @@ static void destroy_hvcs_struct(struct k
spin_unlock_irqrestore(&hvcsd->lock, flags);
spin_unlock(&hvcs_structs_lock);

- hvcs_remove_device_attrs(vdev);
+ sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);

kfree(hvcsd);
}
@@ -608,6 +769,7 @@ static int __devinit hvcs_probe(
{
struct hvcs_struct *hvcsd;
int index;
+ int retval;

if (!dev || !id) {
printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
@@ -658,14 +820,16 @@ static int __devinit hvcs_probe(
* the hvcs_struct has been added to the devices list then the user app
* will get -ENODEV.
*/
-
spin_lock(&hvcs_structs_lock);
-
list_add_tail(&(hvcsd->next), &hvcs_structs);
-
spin_unlock(&hvcs_structs_lock);

- hvcs_create_device_attrs(hvcsd);
+ retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group);
+ if (retval) {
+ printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n",
+ hvcsd->vdev->unit_address);
+ return retval;
+ }

printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);

@@ -1354,8 +1518,10 @@ static int __init hvcs_module_init(void)
if (!hvcs_tty_driver)
return -ENOMEM;

- if (hvcs_alloc_index_list(num_ttys_to_alloc))
- return -ENOMEM;
+ if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
+ rc = -ENOMEM;
+ goto index_fail;
+ }

hvcs_tty_driver->owner = THIS_MODULE;

@@ -1385,41 +1551,57 @@ static int __init hvcs_module_init(void)
* dynamically assigned major and minor numbers for our devices.
*/
if (tty_register_driver(hvcs_tty_driver)) {
- printk(KERN_ERR "HVCS: registration "
- " as a tty driver failed.\n");
- hvcs_free_index_list();
- put_tty_driver(hvcs_tty_driver);
- return -EIO;
+ printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");
+ rc = -EIO;
+ goto register_fail;
}

hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!hvcs_pi_buff) {
- tty_unregister_driver(hvcs_tty_driver);
- hvcs_free_index_list();
- put_tty_driver(hvcs_tty_driver);
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto buff_alloc_fail;
}

hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");
if (IS_ERR(hvcs_task)) {
printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n");
- kfree(hvcs_pi_buff);
- tty_unregister_driver(hvcs_tty_driver);
- hvcs_free_index_list();
- put_tty_driver(hvcs_tty_driver);
- return -EIO;
+ rc = -EIO;
+ goto kthread_fail;
}

rc = vio_register_driver(&hvcs_vio_driver);
+ if (rc) {
+ printk(KERN_ERR "HVCS: can't register vio driver\n");
+ goto vio_fail;
+ }

/*
* This needs to be done AFTER the vio_register_driver() call or else
* the kobjects won't be initialized properly.
*/
- hvcs_create_driver_attrs();
+ rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan);
+ if (rc) {
+ printk(KERN_ERR "HVCS: sysfs attr create failed\n");
+ goto attr_fail;
+ }

printk(KERN_INFO "HVCS: driver module inserted.\n");

+ return 0;
+
+attr_fail:
+ vio_unregister_driver(&hvcs_vio_driver);
+vio_fail:
+ kthread_stop(hvcs_task);
+kthread_fail:
+ kfree(hvcs_pi_buff);
+buff_alloc_fail:
+ tty_unregister_driver(hvcs_tty_driver);
+register_fail:
+ hvcs_free_index_list();
+index_fail:
+ put_tty_driver(hvcs_tty_driver);
+ hvcs_tty_driver = NULL;
return rc;
}

@@ -1441,7 +1623,7 @@ static void __exit hvcs_module_exit(void
hvcs_pi_buff = NULL;
spin_unlock(&hvcs_pi_lock);

- hvcs_remove_driver_attrs();
+ driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);

vio_unregister_driver(&hvcs_vio_driver);

@@ -1456,191 +1638,3 @@ static void __exit hvcs_module_exit(void

module_init(hvcs_module_init);
module_exit(hvcs_module_exit);
-
-static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
-{
- return viod->dev.driver_data;
-}
-/* The sysfs interface for the driver and devices */
-
-static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
- int retval;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
- retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return retval;
-}
-static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
-
-static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
- int retval;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
- retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return retval;
-}
-static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
-
-static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
- size_t count)
-{
- /*
- * Don't need this feature at the present time because firmware doesn't
- * yet support multiple partners.
- */
- printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
- return -EPERM;
-}
-
-static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
- int retval;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
- retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return retval;
-}
-
-static DEVICE_ATTR(current_vty,
- S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
-
-static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
- size_t count)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
-
- /* writing a '0' to this sysfs entry will result in the disconnect. */
- if (simple_strtol(buf, NULL, 0) != 0)
- return -EINVAL;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
-
- if (hvcsd->open_count > 0) {
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- printk(KERN_INFO "HVCS: vterm state unchanged. "
- "The hvcs device node is still in use.\n");
- return -EPERM;
- }
-
- if (hvcsd->connected == 0) {
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- printk(KERN_INFO "HVCS: vterm state unchanged. The"
- " vty-server is not connected to a vty.\n");
- return -EPERM;
- }
-
- hvcs_partner_free(hvcsd);
- printk(KERN_INFO "HVCS: Closed vty-server@%X and"
- " partner vty@%X:%d connection.\n",
- hvcsd->vdev->unit_address,
- hvcsd->p_unit_address,
- (uint32_t)hvcsd->p_partition_ID);
-
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return count;
-}
-
-static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
- int retval;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
- retval = sprintf(buf, "%d\n", hvcsd->connected);
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return retval;
-}
-static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,
- hvcs_vterm_state_show, hvcs_vterm_state_store);
-
-static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
- struct vio_dev *viod = to_vio_dev(dev);
- struct hvcs_struct *hvcsd = from_vio_dev(viod);
- unsigned long flags;
- int retval;
-
- spin_lock_irqsave(&hvcsd->lock, flags);
- retval = sprintf(buf, "%d\n", hvcsd->index);
- spin_unlock_irqrestore(&hvcsd->lock, flags);
- return retval;
-}
-
-static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);
-
-static struct attribute *hvcs_attrs[] = {
- &dev_attr_partner_vtys.attr,
- &dev_attr_partner_clcs.attr,
- &dev_attr_current_vty.attr,
- &dev_attr_vterm_state.attr,
- &dev_attr_index.attr,
- NULL,
-};
-
-static struct attribute_group hvcs_attr_group = {
- .attrs = hvcs_attrs,
-};
-
-static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd)
-{
- struct vio_dev *vdev = hvcsd->vdev;
- sysfs_create_group(&vdev->dev.kobj, &hvcs_attr_group);
-}
-
-static void hvcs_remove_device_attrs(struct vio_dev *vdev)
-{
- sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
-}
-
-static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf)
-{
- /* A 1 means it is updating, a 0 means it is done updating */
- return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);
-}
-
-static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf,
- size_t count)
-{
- if ((simple_strtol(buf, NULL, 0) != 1)
- && (hvcs_rescan_status != 0))
- return -EINVAL;
-
- hvcs_rescan_status = 1;
- printk(KERN_INFO "HVCS: rescanning partner info for all"
- " vty-servers.\n");
- hvcs_rescan_devices_list();
- hvcs_rescan_status = 0;
- return count;
-}
-static DRIVER_ATTR(rescan,
- S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
-
-static void hvcs_create_driver_attrs(void)
-{
- struct device_driver *driverfs = &(hvcs_vio_driver.driver);
- driver_create_file(driverfs, &driver_attr_rescan);
-}
-
-static void hvcs_remove_driver_attrs(void)
-{
- struct device_driver *driverfs = &(hvcs_vio_driver.driver);
- driver_remove_file(driverfs, &driver_attr_rescan);
-}
-
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