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filedesc: iterate over fd table only once in fdcopy

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While here add 'fdused_init' which does not perform unnecessary work.

Drop FILEDESC_LOCK_ASSERT from fdisused and rely on callers to hold
it when appropriate. This function is only used with INVARIANTS.

No functional changes intended.
This commit is contained in:
Mateusz Guzik 2014-10-31 09:19:46 +00:00
parent 1a0c80a3df
commit ffeb890592
1 changed files with 21 additions and 21 deletions
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42
sys/kern/kern_descrip.c
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@ -238,8 +238,6 @@ static int
fdisused(struct filedesc *fdp, int fd)
{
FILEDESC_LOCK_ASSERT(fdp);
KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
@ -250,15 +248,22 @@ fdisused(struct filedesc *fdp, int fd)
/*
* Mark a file descriptor as used.
*/
static void
fdused_init(struct filedesc *fdp, int fd)
{
KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd));
fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
}
static void
fdused(struct filedesc *fdp, int fd)
{
FILEDESC_XLOCK_ASSERT(fdp);
KASSERT(!fdisused(fdp, fd), ("fd=%d is already used", fd));
fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
fdused_init(fdp, fd);
if (fd > fdp->fd_lastfile)
fdp->fd_lastfile = fd;
if (fd == fdp->fd_freefile)
@ -1912,28 +1917,23 @@ fdcopy(struct filedesc *fdp)
newfdp->fd_freefile = -1;
for (i = 0; i <= fdp->fd_lastfile; ++i) {
ofde = &fdp->fd_ofiles[i];
if (ofde->fde_file != NULL &&
ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) {
nfde = &newfdp->fd_ofiles[i];
*nfde = *ofde;
filecaps_copy(&ofde->fde_caps, &nfde->fde_caps);
fhold(nfde->fde_file);
newfdp->fd_lastfile = i;
} else {
if (ofde->fde_file == NULL ||
(ofde->fde_file->f_ops->fo_flags & DFLAG_PASSABLE) == 0) {
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
continue;
}
}
newfdp->fd_cmask = fdp->fd_cmask;
FILEDESC_SUNLOCK(fdp);
FILEDESC_XLOCK(newfdp);
for (i = 0; i <= newfdp->fd_lastfile; ++i) {
if (newfdp->fd_ofiles[i].fde_file != NULL)
fdused(newfdp, i);
nfde = &newfdp->fd_ofiles[i];
*nfde = *ofde;
filecaps_copy(&ofde->fde_caps, &nfde->fde_caps);
fhold(nfde->fde_file);
fdused_init(newfdp, i);
newfdp->fd_lastfile = i;
}
if (newfdp->fd_freefile == -1)
newfdp->fd_freefile = i;
FILEDESC_XUNLOCK(newfdp);
newfdp->fd_cmask = fdp->fd_cmask;
FILEDESC_SUNLOCK(fdp);
return (newfdp);
}