scsi_proc: make proc_scsi_host_open() preallocate a bigger buffer

Some of the ->show_info() instances really spew a lot; it's not a problem
wrt correctness (seq_read() will grow buffer and call the sucker again),
but in this case it makes sense to start with a somewhat bigger one -
they often do exceed one page worth of output.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

drivers/scsi/scsi_proc.c

@@ -78,7 +78,8 @@ static int proc_scsi_show(struct seq_file *m, void *v)
 
 static int proc_scsi_host_open(struct inode *inode, struct file *file)
 {
-	return single_open(file, proc_scsi_show, PDE(inode)->data);
+	return single_open_size(file, proc_scsi_show, PDE(inode)->data,
+				4 * PAGE_SIZE);
 }
 
 static const struct file_operations proc_scsi_fops = {