On Thu, Jun 06, 2024 at 10:54:06PM +0200, Greg Kroah-Hartman wrote: > On Wed, Jun 05, 2024 at 01:29:29PM -0600, Martin Oliveira wrote: > > The standard kernfs vm_ops installs a page_mkwrite() operator which > > modifies the file update time on write. > > > > This not always required (or makes sense), such as in the P2PDMA, which > > uses the sysfs file as an allocator from userspace. > > That's not a good idea, please don't do that. sysfs binary files are > "pass through", why would you want to use this as an allocator? I think the real question is why sysfs binary files implement page_mkwrite by default. page_mkwrite is needed for file systems that need to allocate space from a free space pool, which seems odd for sysfs.
