diff options
| author | anton <anton@cvs.openbsd.org> | 2019-07-10 16:43:21 +0000 |
|---|---|---|
| committer | anton <anton@cvs.openbsd.org> | 2019-07-10 16:43:21 +0000 |
| commit | d8bf193ec09f26b570daa057ab9961744de1794d (patch) | |
| tree | fb42455d3d5d0bb3236d5a9551cade60758d5ad7 /sys/kern/kern_sysctl.c | |
| parent | cfb2b7e76d2d97505ffb3e2ac6a43561e980f07a (diff) | |
Make read/write of the f_offset field belonging to struct file MP-safe;
as part of the effort to unlock the kernel. Instead of relying on the
vnode lock, introduce a dedicated lock per file. Exclusive write access
is granted using the new foffset_enter and foffset_leave API. A
convenience function foffset_get is also available for threads that only
need to read the current offset.
The lock acquisition order in vn_write has been changed to match the one
in vn_read in order to avoid a potential deadlock. This change also gets
rid of a documented race in vn_read().
Inspired by the FreeBSD implementation.
With help and ok mpi@ visa@
Diffstat (limited to 'sys/kern/kern_sysctl.c')
| -rw-r--r-- | sys/kern/kern_sysctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c index 07e85ba692e..06eb7803191 100644 --- a/sys/kern/kern_sysctl.c +++ b/sys/kern/kern_sysctl.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_sysctl.c,v 1.360 2019/06/16 00:56:53 bluhm Exp $ */ +/* $OpenBSD: kern_sysctl.c,v 1.361 2019/07/10 16:43:19 anton Exp $ */ /* $NetBSD: kern_sysctl.c,v 1.17 1996/05/20 17:49:05 mrg Exp $ */ /*- @@ -1100,8 +1100,8 @@ fill_file(struct kinfo_file *kf, struct file *fp, struct filedesc *fdp, kf->f_usecount = 0; if (suser(p) == 0 || p->p_ucred->cr_uid == fp->f_cred->cr_uid) { - kf->f_offset = fp->f_offset; mtx_enter(&fp->f_mtx); + kf->f_offset = fp->f_offset; kf->f_rxfer = fp->f_rxfer; kf->f_rwfer = fp->f_wxfer; kf->f_seek = fp->f_seek; |