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Push Giant acquisition down into fo_stat() from most callers. Acquire

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Giant conditional on debug.mpsafenet in the socket soo_stat() routine,
unconditionally in vn_statfile() for VFS, and otherwise don't acquire
Giant.  Accept an unlocked read in kqueue_stat(), and cryptof_stat() is
a no-op.  Don't acquire Giant in fstat() system call.

Note: in fdescfs, fo_stat() is called while holding Giant due to the VFS
stack sitting on top, and therefore there will still be Giant recursion
in this case.
This commit is contained in:
Robert Watson 2004-07-22 20:40:23 +00:00
parent 0ab1b47fd4
commit a6719c82b1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=132554
4 changed files with 8 additions and 7 deletions
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6
sys/kern/kern_descrip.c
View File

@ -1005,9 +1005,7 @@ ofstat(td, uap)
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0) {
cvtstat(&ub, &oub);
error = copyout(&oub, uap->sb, sizeof(oub));
@ -1042,9 +1040,7 @@ fstat(td, uap)
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0)
error = copyout(&ub, uap->sb, sizeof(ub));
fdrop(fp, td);
@ -1077,9 +1073,7 @@ nfstat(td, uap)
if ((error = fget(td, uap->fd, &fp)) != 0)
goto done2;
mtx_lock(&Giant);
error = fo_stat(fp, &ub, td->td_ucred, td);
mtx_unlock(&Giant);
if (error == 0) {
cvtnstat(&ub, &nub);
error = copyout(&nub, uap->sb, sizeof(nub));

1
sys/kern/kern_event.c
View File

@ -889,6 +889,7 @@ kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred,
{
struct kqueue *kq;
/* Unlocked read. */
kq = fp->f_data;
bzero((void *)st, sizeof(*st));
st->st_size = kq->kq_count;

6
sys/kern/sys_socket.c
View File

@ -225,9 +225,11 @@ soo_stat(fp, ub, active_cred, td)
struct thread *td;
{
struct socket *so = fp->f_data;
int error;
bzero((caddr_t)ub, sizeof (*ub));
ub->st_mode = S_IFSOCK;
NET_LOCK_GIANT();
/*
* If SBS_CANTRCVMORE is set, but there's still data left in the
* receive buffer, the socket is still readable.
@ -244,7 +246,9 @@ soo_stat(fp, ub, active_cred, td)
ub->st_size = so->so_rcv.sb_cc - so->so_rcv.sb_ctl;
ub->st_uid = so->so_cred->cr_uid;
ub->st_gid = so->so_cred->cr_gid;
return ((*so->so_proto->pr_usrreqs->pru_sense)(so, ub));
error = (*so->so_proto->pr_usrreqs->pru_sense)(so, ub);
NET_UNLOCK_GIANT();
return (error);
}
/*

2
sys/kern/vfs_vnops.c
View File

@ -622,9 +622,11 @@ vn_statfile(fp, sb, active_cred, td)
struct vnode *vp = fp->f_vnode;
int error;
mtx_lock(&Giant);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
VOP_UNLOCK(vp, 0, td);
mtx_unlock(&Giant);
return (error);
}