Hoist memcpy_fromiovec/memcpy_toiovec into lib/

ERROR: "memcpy_fromiovec" [drivers/vhost/vhost_scsi.ko] undefined!

That function is only present with CONFIG_NET.  Turns out that
crypto/algif_skcipher.c also uses that outside net, but it actually
needs sockets anyway.

In addition, commit 6d4f0139d642c45411a47879325891ce2a7c164a added
CONFIG_NET dependency to CONFIG_VMCI for memcpy_toiovec, so hoist
that function and revert that commit too.

socket.h already includes uio.h, so no callers need updating; trying
only broke things fo x86_64 randconfig (thanks Fengguang!).

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 53 insertions, 0 deletions

diff --git a/lib/iovec.c b/lib/iovec.c
new file mode 100644
index 00000000000..454baa88bf2
--- /dev/null
+++ b/lib/iovec.c
@@ -0,0 +1,53 @@
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/uio.h>
+
+/*
+ *	Copy iovec to kernel. Returns -EFAULT on error.
+ *
+ *	Note: this modifies the original iovec.
+ */
+
+int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
+{
+	while (len > 0) {
+		if (iov->iov_len) {
+			int copy = min_t(unsigned int, len, iov->iov_len);
+			if (copy_from_user(kdata, iov->iov_base, copy))
+				return -EFAULT;
+			len -= copy;
+			kdata += copy;
+			iov->iov_base += copy;
+			iov->iov_len -= copy;
+		}
+		iov++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_fromiovec);
+
+/*
+ *	Copy kernel to iovec. Returns -EFAULT on error.
+ *
+ *	Note: this modifies the original iovec.
+ */
+
+int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
+{
+	while (len > 0) {
+		if (iov->iov_len) {
+			int copy = min_t(unsigned int, iov->iov_len, len);
+			if (copy_to_user(iov->iov_base, kdata, copy))
+				return -EFAULT;
+			kdata += copy;
+			len -= copy;
+			iov->iov_len -= copy;
+			iov->iov_base += copy;
+		}
+		iov++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(memcpy_toiovec);