Push Giant down through select and poll.

Don't grab Giant in the upper syscall/wrapper code

NET_LOCK_GIANT in the socket code (sockets/fifos).

mtx_lock(&Giant) in the vnode code.

Devfs grabs Giant if the driver is marked as needing Giant.

3 files changed, 5 insertions, 13 deletions

diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 6f2d551..c90ce5c 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -625,11 +625,7 @@ kern_select(struct thread *td, int nd, fd_set *fd_in, fd_set *fd_ou,
 	if (nd < 0)
 		return (EINVAL);
 	fdp = td->td_proc->p_fd;
-	/*
-	 * XXX: kern_select() currently requires that we acquire Giant
-	 * even if none of the file descriptors we poll requires Giant.
-	 */
-	mtx_lock(&Giant);
+	
 	FILEDESC_LOCK_FAST(fdp);
 
 	if (nd > td->td_proc->p_fd->fd_nfiles)
@@ -764,7 +760,6 @@ done_nosellock:
 	if (selbits != &s_selbits[0])
 		free(selbits, M_SELECT);
 
-	mtx_unlock(&Giant);
 	return (error);
 }
 
@@ -838,11 +833,6 @@ poll(td, uap)
 	nfds = uap->nfds;
 
 	/*
-	 * XXX: poll() currently requires that we acquire Giant even if
-	 * none of the file descriptors we poll requires Giant.
-	 */
-	mtx_lock(&Giant);
-	/*
 	 * This is kinda bogus.  We have fd limits, but that is not
 	 * really related to the size of the pollfd array.  Make sure
 	 * we let the process use at least FD_SETSIZE entries and at
@@ -943,7 +933,6 @@ out:
 	if (ni > sizeof(smallbits))
 		free(bits, M_TEMP);
 done2:
-	mtx_unlock(&Giant);
 	return (error);
 }
 
diff --git a/sys/kern/sys_socket.c b/sys/kern/sys_socket.c
index f40d230..4a7911d 100644
--- a/sys/kern/sys_socket.c
+++ b/sys/kern/sys_socket.c
@@ -223,8 +223,10 @@ soo_poll(fp, events, active_cred, td)
 	struct socket *so = fp->f_data;
 	int error;
 
+	NET_LOCK_GIANT();
 	error = (so->so_proto->pr_usrreqs->pru_sopoll)
 	    (so, events, fp->f_cred, td);
+	NET_UNLOCK_GIANT();
 
 	return (error);
 }
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 37204f3..cd5e669 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -850,7 +850,7 @@ vn_poll(fp, events, active_cred, td)
 	struct vnode *vp;
 	int error;
 
-	GIANT_REQUIRED;
+	mtx_lock(&Giant);
 
 	vp = fp->f_vnode;
 #ifdef MAC
@@ -861,6 +861,7 @@ vn_poll(fp, events, active_cred, td)
 #endif
 
 	error = VOP_POLL(vp, events, fp->f_cred, td);
+	mtx_unlock(&Giant);
 	return (error);
 }