diff --git a/share/man/man9/copy.9 b/share/man/man9/copy.9
index b6b975f..6008934 100644
--- a/share/man/man9/copy.9
+++ b/share/man/man9/copy.9
@@ -34,13 +34,15 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 7, 1996
+.Dd March 20, 2011
 .Dt COPY 9
 .Os
 .Sh NAME
 .Nm copy ,
 .Nm copyin ,
+.Nm copyin_nofault ,
 .Nm copyout ,
+.Nm copyout_nofault ,
 .Nm copystr ,
 .Nm copyinstr
 .Nd kernel copy functions
@@ -50,8 +52,12 @@
 .Ft int
 .Fn copyin "const void *uaddr" "void *kaddr" "size_t len"
 .Ft int
+.Fn copyin_nofault "const void *uaddr" "void *kaddr" "size_t len"
+.Ft int
 .Fn copyout "const void *kaddr" "void *uaddr" "size_t len"
 .Ft int
+.Fn copyout_nofault "const void *kaddr" "void *uaddr" "size_t len"
+.Ft int
 .Fn copystr "const void *kfaddr" "void *kdaddr" "size_t len" "size_t *done"
 .Ft int
 .Fn copyinstr "const void *uaddr" "void *kaddr" "size_t len" "size_t *done"
@@ -70,20 +76,34 @@ The
 .Nm
 routines provide the following functionality:
 .Bl -tag -width "copyoutstr()"
-.It Fn copyin
-Copies
+.It Fn copyin ,
+.It Fn copyin_nofault
+Copy
 .Fa len
 bytes of data from the user-space address
 .Fa uaddr
 to the kernel-space address
 .Fa kaddr .
-.It Fn copyout
-Copies
+The
+.Fn copyin_nofault
+will not handle the page-in for valid user address that does not have
+the backing page resident, returning
+.Er EFAULT
+instead.
+.It Fn copyout ,
+.It Fn copyout_nofault
+Copy
 .Fa len
 bytes of data from the kernel-space address
 .Fa kaddr
 to the user-space address
 .Fa uaddr .
+The
+.Fn copyout_nofault
+will not handle the page-in for valid user address that does not have
+the backing page resident, returning
+.Er EFAULT
+instead.
 .It Fn copystr
 Copies a NUL-terminated string, at most
 .Fa len
diff --git a/share/man/man9/uio.9 b/share/man/man9/uio.9
index fb27c9c..c14564f 100644
--- a/share/man/man9/uio.9
+++ b/share/man/man9/uio.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 21, 2010
+.Dd March 20, 2011
 .Dt UIO 9
 .Os
 .Sh NAME
@@ -48,10 +48,14 @@ struct uio {
 .Ed
 .Ft int
 .Fn uiomove "void *buf" "int howmuch" "struct uio *uiop"
+.Ft int
+.Fn uiomove_nofault "void *buf" "int howmuch" "struct uio *uiop"
 .Sh DESCRIPTION
-The function
+The functions
 .Fn uiomove
-is used to handle transfer of data between buffers and I/O vectors
+and
+.Fn uiomove_nofault
+are used to handle transfer of data between buffers and I/O vectors
 that might possibly also cross the user/kernel space boundary.
 .Pp
 As a result of any
@@ -110,6 +114,21 @@ for the associated thread; used if
 indicates that the transfer is to be made from/to a process's address
 space.
 .El
+.Pp
+The function
+.Fn uiomove_nofault
+will not handle the page-in for valid user address that does not have
+the backing page resident, returning
+.Er EFAULT
+instead.
+It is the caller responsibility to make sure that the pages are resident
+before the call, for instance, by using
+.Xr vm_fault_quick_hold_pages 9
+service.
+Then, the
+.Fn uiomove_nofault
+can be called from the context that disallows sleep or where recursing
+into virtual memory system locks is prohibited.
 .Sh RETURN VALUES
 On success
 .Fn uiomove
diff --git a/sys/kern/subr_uio.c b/sys/kern/subr_uio.c
index 9385dc4..f09c927 100644
--- a/sys/kern/subr_uio.c
+++ b/sys/kern/subr_uio.c
@@ -64,6 +64,8 @@ __FBSDID("$FreeBSD$");
 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV,
 	"Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
 
+static int uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault);
+
 #ifdef ZERO_COPY_SOCKETS
 /* Declared in uipc_socket.c */
 extern int so_zero_copy_receive;
@@ -129,23 +131,66 @@ retry:
 #endif /* ZERO_COPY_SOCKETS */
 
 int
+copyin_nofault(const void *udaddr, void *kaddr, size_t len)
+{
+	int error, save;
+
+	save = vm_fault_disable_pagefaults();
+	error = copyin(udaddr, kaddr, len);
+	vm_fault_enable_pagefaults(save);
+	return (error);
+}
+
+int
+copyout_nofault(const void *kaddr, void *udaddr, size_t len)
+{
+	int error, save;
+
+	save = vm_fault_disable_pagefaults();
+	error = copyout(kaddr, udaddr, len);
+	vm_fault_enable_pagefaults(save);
+	return (error);
+}
+
+int
 uiomove(void *cp, int n, struct uio *uio)
 {
-	struct thread *td = curthread;
+
+	return (uiomove_faultflag(cp, n, uio, 0));
+}
+
+int
+uiomove_nofault(void *cp, int n, struct uio *uio)
+{
+
+	return (uiomove_faultflag(cp, n, uio, 1));
+}
+
+static int
+uiomove_faultflag(void *cp, int n, struct uio *uio, int nofault)
+{
+	struct thread *td;
 	struct iovec *iov;
 	u_int cnt;
-	int error = 0;
-	int save = 0;
+	int error, newflags, save;
+
+	td = curthread;
+	error = 0;
 
 	KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
 	    ("uiomove: mode"));
-	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
+	KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == td,
 	    ("uiomove proc"));
-	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
-	    "Calling uiomove()");
+	if (!nofault)
+		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
+		    "Calling uiomove()");
 
-	save = td->td_pflags & TDP_DEADLKTREAT;
-	td->td_pflags |= TDP_DEADLKTREAT;
+	/* XXX does it make a sense to set TDP_DEADLKTREAT for UIO_SYSSPACE ? */
+	newflags = TDP_DEADLKTREAT;
+	if (uio->uio_segflg == UIO_USERSPACE && nofault)
+		newflags |= TDP_NSLPPFAULT;
+	save = ~newflags | (td->td_pflags & newflags);
+	td->td_pflags |= newflags;
 
 	while (n > 0 && uio->uio_resid) {
 		iov = uio->uio_iov;
@@ -187,8 +232,7 @@ uiomove(void *cp, int n, struct uio *uio)
 		n -= cnt;
 	}
 out:
-	if (save == 0)
-		td->td_pflags &= ~TDP_DEADLKTREAT;
+	td->td_pflags &= save;
 	return (error);
 }
 
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index c54a956..157bad1 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -393,7 +393,7 @@ do {									\
 #define	TDP_COWINPROGRESS 0x00000010 /* Snapshot copy-on-write in progress. */
 #define	TDP_ALTSTACK	0x00000020 /* Have alternate signal stack. */
 #define	TDP_DEADLKTREAT	0x00000040 /* Lock aquisition - deadlock treatment. */
-#define	TDP_UNUSED80	0x00000080 /* available. */
+#define	TDP_NSLPPFAULT	0x00000080 /* Do not sleep in the page fault handler. */
 #define	TDP_NOSLEEPING	0x00000100 /* Thread is not allowed to sleep on a sq. */
 #define	TDP_OWEUPC	0x00000200 /* Call addupc() at next AST. */
 #define	TDP_ITHREAD	0x00000400 /* Thread is an interrupt thread. */
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 35d34e4..8b0de57 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -217,8 +217,12 @@ int	copyinstr(const void * __restrict udaddr, void * __restrict kaddr,
 	    __nonnull(1) __nonnull(2);
 int	copyin(const void * __restrict udaddr, void * __restrict kaddr,
 	    size_t len) __nonnull(1) __nonnull(2);
+int	copyin_nofault(const void * __restrict udaddr, void * __restrict kaddr,
+	    size_t len) __nonnull(1) __nonnull(2);
 int	copyout(const void * __restrict kaddr, void * __restrict udaddr,
 	    size_t len) __nonnull(1) __nonnull(2);
+int	copyout_nofault(const void * __restrict kaddr, void * __restrict udaddr,
+	    size_t len) __nonnull(1) __nonnull(2);
 
 int	fubyte(const void *base);
 long	fuword(const void *base);
diff --git a/sys/sys/uio.h b/sys/sys/uio.h
index d7fa124..45a5740 100644
--- a/sys/sys/uio.h
+++ b/sys/sys/uio.h
@@ -97,6 +97,7 @@ int	copyinuio(struct iovec *iovp, u_int iovcnt, struct uio **uiop);
 int	copyout_map(struct thread *td, vm_offset_t *addr, size_t sz);
 int	copyout_unmap(struct thread *td, vm_offset_t addr, size_t sz);
 int	uiomove(void *cp, int n, struct uio *uio);
+int	uiomove_nofault(void *cp, int n, struct uio *uio);
 int	uiomove_frombuf(void *buf, int buflen, struct uio *uio);
 int	uiomove_fromphys(struct vm_page *ma[], vm_offset_t offset, int n,
 	    struct uio *uio);
diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 55abe86..2ab3342 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -209,6 +209,8 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
     int fault_flags)
 {
 
+	if ((curthread->td_pflags & TDP_NSLPPFAULT) != 0)
+		return (KERN_PROTECTION_FAILURE);
 	return (vm_fault_hold(map, vaddr, fault_type, fault_flags, NULL));
 }
 
@@ -1475,3 +1477,22 @@ vm_fault_additional_pages(m, rbehind, rahead, marray, reqpage)
 	/* return number of pages */
 	return i;
 }
+
+int
+vm_fault_disable_pagefaults(void)
+{
+	struct thread *td;
+	int save;
+
+	td = curthread;
+	save = ~TDP_NSLPPFAULT | (td->td_pflags & TDP_NSLPPFAULT);
+	td->td_pflags |= TDP_NSLPPFAULT;
+	return (save);
+}
+
+void
+vm_fault_enable_pagefaults(int save)
+{
+
+	curthread->td_pflags &= save;
+}