The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=45bb8beacc2fadbbc32428df0f2f5683863df289
commit 45bb8beacc2fadbbc32428df0f2f5683863df289 Author: Mateusz Guzik <[email protected]> AuthorDate: 2022-02-01 16:58:12 +0000 Commit: Mateusz Guzik <[email protected]> CommitDate: 2022-02-11 12:29:26 +0000 fd: elide one acquire fence in fget_unlocked_seq Still validate we got the stable state before returning an error though. --- sys/kern/kern_descrip.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index c4f435002907..e5ffdb01255f 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -3060,13 +3060,19 @@ fget_unlocked_seq(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, fde = &fdt->fdt_ofiles[fd]; haverights = *cap_rights_fde_inline(fde); fp = fde->fde_file; - if (!seqc_consistent(fd_seqc(fdt, fd), seq)) + if (__predict_false(fp == NULL)) { + if (seqc_consistent(fd_seqc(fdt, fd), seq)) + return (EBADF); + fdt = atomic_load_ptr(&fdp->fd_files); continue; - if (__predict_false(fp == NULL)) - return (EBADF); + } error = cap_check_inline(&haverights, needrightsp); - if (__predict_false(error != 0)) - return (error); + if (__predict_false(error != 0)) { + if (seqc_consistent(fd_seqc(fdt, fd), seq)) + return (error); + fdt = atomic_load_ptr(&fdp->fd_files); + continue; + } if (__predict_false(!refcount_acquire_if_not_zero(&fp->f_count))) { fdt = atomic_load_ptr(&fdp->fd_files); continue;
