Date: Mon, 6 Dec 2021 17:21:24 +0000 From: Brooks Davis <brooks@freebsd.org> To: Konstantin Belousov <kib@FreeBSD.org> Cc: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: a4e4132fa3bf - main - swapoff(2): replace special device name argument with a structure Message-ID: <20211206172124.GA40392@spindle.one-eyed-alien.net> In-Reply-To: <202112042221.1B4ML7Ov002151@gitrepo.freebsd.org> References: <202112042221.1B4ML7Ov002151@gitrepo.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--opJtzjQTFsWo+cga Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Dec 04, 2021 at 10:21:07PM +0000, Konstantin Belousov wrote: > The branch main has been updated by kib: >=20 > URL: https://cgit.FreeBSD.org/src/commit/?id=3Da4e4132fa3bfadb6047fc0fa5f= 399f4640460300 >=20 > commit a4e4132fa3bfadb6047fc0fa5f399f4640460300 > Author: Konstantin Belousov <kib@FreeBSD.org> > AuthorDate: 2021-11-29 16:26:31 +0000 > Commit: Konstantin Belousov <kib@FreeBSD.org> > CommitDate: 2021-12-04 22:20:58 +0000 >=20 > swapoff(2): replace special device name argument with a structure > =20 > For compatibility, add a placeholder pointer to the start of the > added struct swapoff_new_args, and use it to distinguish old vs. new > style of syscall invocation. I agree with Jess that this should be a new syscall. The entry in sycalls.master now fails to describe the memory footprint of the name argument. No system call should be created or altered to have a memory footprint not describable with SAL annotations unless an applicable standard such as POSIX requires it. > diff --git a/sys/vm/swap_pager.h b/sys/vm/swap_pager.h > index 395fbc9957c4..469de3e8eaf4 100644 > --- a/sys/vm/swap_pager.h > +++ b/sys/vm/swap_pager.h > @@ -69,6 +69,14 @@ struct swdevt { > #define SW_UNMAPPED 0x01 > #define SW_CLOSING 0x04 > =20 > +struct swapoff_new_args { > + const char *name_old_syscall; > + const char *name; > + u_int flags; > + u_int pad0; > + uintptr_t pad1[8]; > +}; If you're going to attempt to add future-proofing, please pad with the assumption that pointers are 128-bit sized and aligned. In this case, that would mean an uint64_t pad before pad1. If there were done in place, adding the pad and dropping pad1 to 6 elements would be safe. -- Brooks --opJtzjQTFsWo+cga Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJhrkaTAAoJEKzQXbSebgfA0RMH/AhaygTxl8kC4hjJrjjpKwZG pOlX+qdN1yeaTRHmsxa0QMSJ7Zau+QS0vqXQB3RnBZr+QPqrqxuzqh75rJyryzMT TBvEwNcAI7Gk/6Z9wHZf8S8FQXKHLVvkO/HcmtqoPSWFCxUYx/cYV3e4PLcwdFWo lCG1SVsxdv2imiTTdXBl5wTP6DmIvLhVpJfh69DU4Km3kLuj7iwI1l+UKhVgyfij CNwN/jSJI3KQQZDdeswBjPd1KL0lNisHztYZXya2nYPxsLWuIqK7y/GLPjvpDCI7 tjVrcm2RIY+SxVbauKTmoCUqelM3RNbwzS53NASU0/uiKXB4eFrpd+FbwvVcYm8= =ooqx -----END PGP SIGNATURE----- --opJtzjQTFsWo+cga--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20211206172124.GA40392>