On Fri, Jun 26, 2020 at 12:27:52PM +0000, Luis Chamberlain wrote: > On Fri, Jun 26, 2020 at 09:58:35AM +0200, Christoph Hellwig wrote: > > diff --git a/fs/read_write.c b/fs/read_write.c > > index e765c95ff3440d..ae463bcadb6906 100644 > > --- a/fs/read_write.c > > +++ b/fs/read_write.c > > @@ -420,6 +420,18 @@ ssize_t iter_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos, > > return ret; > > } > > > > +static void warn_unsupported(struct file *file, const char *op) > > +{ > > + char pathname[128], *path; > > Why 128? How about kstrdup_quotable_file()? This is in the read/write path for the case where we did not end up calling in the driver. This is far less stack usage than any read/write method would have used eventually.