new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
index d1f0120..5e1e12c 100644
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -640,7 +640,7 @@
 /* This function handles ioctl for the character device */
 static long twa_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	struct inode *inode = file->f_path.dentry->d_inode;
+	struct inode *inode = file_inode(file);
 	long timeout;
 	unsigned long *cpu_addr, data_buffer_length_adjusted = 0, flags = 0;
 	dma_addr_t dma_handle;