# Re: \[PATCH 6/9\] kernel/api: add API specification for sys\_close

- From: Greg Kroah-Hartman \<gregkh@linuxfoundation.org\>
- Date: 2026-03-13 15:52:35 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2026/03/343388
- Thread: https://ratatoskr.run/linux-api/2026/03/343369/t.md

```text
On Fri, Mar 13, 2026 at 11:09:16AM -0400, Sasha Levin wrote:
> + * notes: This syscall has subtle non-POSIX semantics: the fd is ALWAYS closed
> + *   regardless of the return value. POSIX specifies that on EINTR, the state
> + *   of the fd is unspecified, but Linux always closes it. HP-UX requires
> + *   retrying close() on EINTR, but doing so on Linux may close an unrelated
> + *   fd that was reassigned by another thread. For portable code, the safest
> + *   approach is to check for errors but never retry close().

We don't care about HP-UX :)

> + *   Error codes from the flush callback (EIO, ENOSPC, EDQUOT) indicate that
> + *   previously written data may have been lost. These errors are particularly
> + *   common on NFS where write errors are often deferred to close time.

What flush callback?


> + *
> + *   The driver's release() callback errors are explicitly ignored by the
> + *   kernel, so device driver cleanup errors are not propagated to userspace.

What "The driver" here?  release() callbacks aren't really relevant
here.

thanks,

greg k-h
```