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poll: factor fd lookup out of scan and rescan

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This commit is contained in:
Mateusz Guzik 2020-07-15 10:24:39 +00:00
parent d8bc2a17a5
commit b1607c8727
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=363215
1 changed files with 70 additions and 43 deletions
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113
sys/kern/sys_generic.c
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@ -1476,6 +1476,49 @@ sys_ppoll(struct thread *td, struct ppoll_args *uap)
return (kern_poll(td, uap->fds, uap->nfds, tsp, ssp));
}
#ifdef CAPABILITIES
static int
poll_fget(struct filedesc *fdp, int fd, struct file **fpp)
{
const struct filedescent *fde;
const struct fdescenttbl *fdt;
const cap_rights_t *haverights;
struct file *fp;
int error;
if (__predict_false(fd >= fdp->fd_nfiles))
return (EBADF);
fdt = fdp->fd_files;
fde = &fdt->fdt_ofiles[fd];
fp = fde->fde_file;
if (__predict_false(fp == NULL))
return (EBADF);
haverights = cap_rights_fde_inline(fde);
error = cap_check_inline(haverights, &cap_event_rights);
if (__predict_false(error != 0))
return (EBADF);
*fpp = fp;
return (0);
}
#else
static int
poll_fget(struct filedesc *fdp, int fd, struct file **fpp)
{
struct file *fp;
if (__predict_false(fd >= fdp->fd_nfiles))
return (EBADF);
fp = fdp->fd_ofiles[fd].fde_file;
if (__predict_false(fp == NULL))
return (EBADF);
*fpp = fp;
return (0);
}
#endif
static int
pollrescan(struct thread *td)
{
@ -1499,19 +1542,11 @@ pollrescan(struct thread *td)
/* If the selinfo wasn't cleared the event didn't fire. */
if (si != NULL)
continue;
fp = fdp->fd_ofiles[fd->fd].fde_file;
#ifdef CAPABILITIES
if (fp == NULL ||
cap_check(cap_rights(fdp, fd->fd), &cap_event_rights) != 0)
#else
if (fp == NULL)
#endif
{
if (poll_fget(fdp, fd->fd, &fp) != 0) {
fd->revents = POLLNVAL;
n++;
continue;
}
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
@ -1550,47 +1585,39 @@ pollout(struct thread *td, struct pollfd *fds, struct pollfd *ufds, u_int nfd)
static int
pollscan(struct thread *td, struct pollfd *fds, u_int nfd)
{
struct filedesc *fdp = td->td_proc->p_fd;
struct filedesc *fdp;
struct file *fp;
int i, n = 0;
int i, n;
n = 0;
fdp = td->td_proc->p_fd;
FILEDESC_SLOCK(fdp);
for (i = 0; i < nfd; i++, fds++) {
if (fds->fd >= fdp->fd_nfiles) {
if (fds->fd < 0) {
fds->revents = 0;
continue;
}
if (poll_fget(fdp, fds->fd, &fp) != 0) {
fds->revents = POLLNVAL;
n++;
} else if (fds->fd < 0) {
fds->revents = 0;
} else {
fp = fdp->fd_ofiles[fds->fd].fde_file;
#ifdef CAPABILITIES
if (fp == NULL ||
cap_check(cap_rights(fdp, fds->fd), &cap_event_rights) != 0)
#else
if (fp == NULL)
#endif
{
fds->revents = POLLNVAL;
n++;
} else {
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
*/
selfdalloc(td, fds);
fds->revents = fo_poll(fp, fds->events,
td->td_ucred, td);
/*
* POSIX requires POLLOUT to be never
* set simultaneously with POLLHUP.
*/
if ((fds->revents & POLLHUP) != 0)
fds->revents &= ~POLLOUT;
if (fds->revents != 0)
n++;
}
continue;
}
/*
* Note: backend also returns POLLHUP and
* POLLERR if appropriate.
*/
selfdalloc(td, fds);
fds->revents = fo_poll(fp, fds->events,
td->td_ucred, td);
/*
* POSIX requires POLLOUT to be never
* set simultaneously with POLLHUP.
*/
if ((fds->revents & POLLHUP) != 0)
fds->revents &= ~POLLOUT;
if (fds->revents != 0)
n++;
}
FILEDESC_SUNLOCK(fdp);
td->td_retval[0] = n;