Re: [PATCH 2/2] staging: unisys: added virtpci info entry

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On Tue, Jul 08, 2014 at 01:21:31PM -0400, Erik Arfvidson wrote:
> This patch adds the virtpci debugfs directory and the info entry
> inside of it.
> 
> Signed-off-by: Erik Arfvidson <erik.arfvidson@xxxxxxxxxx>
> Signed-off-by: Benjamin Romer <benjamin.romer@xxxxxxxxxx>
> ---
>  drivers/staging/unisys/virtpci/virtpci.c | 122 ++++++++++++++++++++++++++++++-
>  1 file changed, 118 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/unisys/virtpci/virtpci.c b/drivers/staging/unisys/virtpci/virtpci.c
> index 7d840b0..6c0aa96 100644
> --- a/drivers/staging/unisys/virtpci/virtpci.c
> +++ b/drivers/staging/unisys/virtpci/virtpci.c
> @@ -37,6 +37,7 @@
>  #include <linux/if_ether.h>
>  #include <linux/version.h>
>  #include "version.h"
> + #include <linux/debugfs.h>
>  #include "guestlinuxdebug.h"
>  #include "timskmodutils.h"
>  
> @@ -100,6 +101,12 @@ static int virtpci_device_resume(struct device *dev);
>  static int virtpci_device_probe(struct device *dev);
>  static int virtpci_device_remove(struct device *dev);
>  
> +static ssize_t info_debugfs_read(struct file *file, char __user *buf,
> +			      size_t len, loff_t *offset);
> +
> +static const struct file_operations debugfs_info_fops = {
> +	.read = info_debugfs_read,
> +};
>  
>  /*****************************************************/
>  /* Globals                                           */
> @@ -139,7 +146,19 @@ static DEFINE_RWLOCK(VpcidevListLock);
>  
>  /* filled in with info about this driver, wrt it servicing client busses */
>  static ULTRA_VBUS_DEVICEINFO Bus_DriverInfo;
> -
> +		/*****************************************************/
> +		/* DebugFS entries                                   */
> +		/*****************************************************/
> +/* dentry is used to create the debugfs entry directory
> + * for virtpci
> + */
> +static struct dentry *virtpci_debugfs_dir;
> +static struct dentry *info_debugfs_entry;
> +/* info_debugfs_entry is used to tell virtpci to display current info
> + * kept in the driver
> + */
> +#define DIR_DEBUGFS_ENTRY "virtpci"
> +#define INFO_DEBUGFS_ENTRY_FN "info"
>  
>  struct virtpci_busdev {
>  	struct device virtpci_bus_device;
> @@ -588,7 +607,8 @@ static void delete_all(void)
>  /* deletes all vnics or vhbas
>   * returns 0 failure, 1 success,
>   */
> -static int delete_all_virt(VIRTPCI_DEV_TYPE devtype, struct del_vbus_guestpart *delparams)
> +static int delete_all_virt(VIRTPCI_DEV_TYPE devtype,
> +			struct del_vbus_guestpart *delparams)
>  {
>  	int i;
>  	unsigned char busid[BUS_ID_SIZE];
> @@ -1375,6 +1395,95 @@ void virtpci_unregister_driver(struct virtpci_driver *drv)
>  	DBGINF("Leaving\n");
>  }
>  EXPORT_SYMBOL_GPL(virtpci_unregister_driver);
> +/*****************************************************/
> +/* debugfs filesystem functions						*/
> +/*****************************************************/
> +struct print_vbus_info {
> +	int *length;
> +	char *buf;
> +};
> +
> +static int print_vbus(struct device *vbus, void *data)
> +{
> +	struct print_vbus_info *p = (struct print_vbus_info *) data;

Remove the space after the cast to remind that casting is high
precedence.

	struct print_vbus_info *p = (struct print_vbus_info *)data;

> +	int l = *(p->length);

Remove the extra parens.

	int l = *p->length;

> +
> +	*(p->length) = l + sprintf(p->buf + l, "bus_id:%s\n", dev_name(vbus));

You don't really need the "l" at all.

	*p->length += sprintf(p->buf + *p->length, "bus_id:%s\n",
			      dev_name(vbus));

> +	return 0;		/* no error */
> +}
> +
> +static ssize_t info_debugfs_read(struct file *file, char __user *buf,
> +			      size_t len, loff_t *offset)
> +{
> +	int length = 0;

"length" is going to be confusing because we already have "len".

> +	struct virtpci_dev *tmpvpcidev;
> +	unsigned long flags;
> +	struct print_vbus_info printparam;
> +	char *vbuf;
> +	loff_t pos = *offset;
> +
> +	if (pos < 0)
> +		return -EINVAL;
> +
> +	if (pos > 0 || !len)
> +		return 0;

I don't understand the point of updating *offset and then not allowing
pos > 0.  (This could be because I haven't paid attention as well
though).

> +
> +	vbuf = kzalloc(len, GFP_KERNEL);
> +	if (!vbuf)
> +		return -ENOMEM;
> +
> +	length += sprintf(vbuf + length, "CHANSOCK is not defined.\n");


This is memory corruption here because we don't verify that len is large
enough for the string.  None of the sprintf() calls have checking.

> +
> +	length += sprintf(vbuf + length, "\n Virtual PCI Bus devices\n");
> +	printparam.length = &length;
> +	printparam.buf = vbuf;
> +	if (bus_for_each_dev(&virtpci_bus_type, NULL,
> +			     (void *) &printparam, print_vbus))
> +		LOGERR("delete of all vbus failed\n");

"delete"?  Probably cut and paste bug.

> +
> +	length += sprintf(vbuf + length, "\n Virtual PCI devices\n");
> +	read_lock_irqsave(&VpcidevListLock, flags);
> +	tmpvpcidev = VpcidevListHead;
> +	while (tmpvpcidev) {
> +		if (tmpvpcidev->devtype == VIRTHBA_TYPE) {
> +			length += sprintf(vbuf + length,
> +					"[%d:%d] VHba:%08x:%08x max-config:%d-%d-%d-%d",
> +				    tmpvpcidev->busNo, tmpvpcidev->deviceNo,
> +				    tmpvpcidev->scsi.wwnn.wwnn1,
> +				    tmpvpcidev->scsi.wwnn.wwnn2,
> +				    tmpvpcidev->scsi.max.max_channel,
> +				    tmpvpcidev->scsi.max.max_id,
> +				    tmpvpcidev->scsi.max.max_lun,
> +				    tmpvpcidev->scsi.max.cmd_per_lun);
> +		} else {
> +			length += sprintf(vbuf + length, "[%d:%d] VNic:%02x:%02x:%02x:%02x:%02x:%02x num_rcv_bufs:%d mtu:%d",
> +				    tmpvpcidev->busNo, tmpvpcidev->deviceNo,
> +				    tmpvpcidev->net.mac_addr[0],
> +				    tmpvpcidev->net.mac_addr[1],
> +				    tmpvpcidev->net.mac_addr[2],
> +				    tmpvpcidev->net.mac_addr[3],
> +				    tmpvpcidev->net.mac_addr[4],
> +				    tmpvpcidev->net.mac_addr[5],
> +				    tmpvpcidev->net.num_rcv_bufs,
> +				    tmpvpcidev->net.mtu);
> +		}
> +		length +=
> +		    sprintf(vbuf + length, " chanptr:%p\n",
> +			    tmpvpcidev->queueinfo.chan);
> +		tmpvpcidev = tmpvpcidev->next;
> +	}
> +	read_unlock_irqrestore(&VpcidevListLock, flags);
> +
> +	length += sprintf(vbuf + length, "\n");
> +	if (copy_to_user(buf, vbuf, length)) {

There should be some length checking here as well.

> +		kfree(vbuf);
> +		return -EFAULT;
> +	}
> +
> +	kfree(vbuf);
> +	*offset += length;
> +	return length;
> +}
>  
>  /*****************************************************/
>  /* Module Init & Exit functions                      */
> @@ -1426,7 +1535,10 @@ static int __init virtpci_mod_init(void)
>  
>  	LOGINF("successfully registered virtpci_ctrlchan_func (0x%p) as callback.\n",
>  	     (void *) &virtpci_ctrlchan_func);
> -
> +	/*create debugfs directory*/
> +	virtpci_debugfs_dir = debugfs_create_dir(DIR_DEBUGFS_ENTRY, NULL);
> +	info_debugfs_entry = debugfs_create_file(INFO_DEBUGFS_ENTRY_FN, 0660,

The owner has write permision but there is no ->write op.  Don't use the
numbers use S_IRUSR or whatever.

> +				virtpci_debugfs_dir, NULL, &debugfs_info_fops);
>  	LOGINF("Leaving\n");
>  	POSTCODE_LINUX_2(VPCI_CREATE_EXIT_PC, POSTCODE_SEVERITY_INFO);
>  	return 0;
> @@ -1442,7 +1554,9 @@ static void __exit virtpci_mod_exit(void)
>  
>  	device_unregister(&virtpci_rootbus_device);
>  	bus_unregister(&virtpci_bus_type);
> -
> +	/*debug_fs file and direcroty removal*/
> +		debugfs_remove(info_debugfs_entry);
> +		debugfs_remove(virtpci_debugfs_dir);

These are not indented correctly.

regards,
dan carpenter

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