iovec: move memcpy_from/toiovecend to lib/iovec.c

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

commit 9f977ef7b671f6169eca78bf40f230fe84b7c7e5
    vhost-scsi: Include prot_bytes into expected data transfer length
in target-pending makes drivers/vhost/scsi.c call memcpy_fromiovecend().
This function is not available when CONFIG_NET is not enabled.

socket.h already includes uio.h, so no callers need updating.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/lib/iovec.c b/lib/iovec.c
index 454baa88bf27..7a7c2da4cddf 100644
--- a/lib/iovec.c
+++ b/lib/iovec.c
@@ -51,3 +51,58 @@ int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
         return 0;
 }
 EXPORT_SYMBOL(memcpy_toiovec);
+
+/*
+ *      Copy kernel to iovec. Returns -EFAULT on error.
+ */
+
+int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
+                      int offset, int len)
+{
+        int copy;
+        for (; len > 0; ++iov) {
+                /* Skip over the finished iovecs */
+                if (unlikely(offset >= iov->iov_len)) {
+                        offset -= iov->iov_len;
+                        continue;
+                }
+                copy = min_t(unsigned int, iov->iov_len - offset, len);
+                if (copy_to_user(iov->iov_base + offset, kdata, copy))
+                        return -EFAULT;
+                offset = 0;
+                kdata += copy;
+                len -= copy;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(memcpy_toiovecend);
+
+/*
+ *      Copy iovec to kernel. Returns -EFAULT on error.
+ */
+
+int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
+                        int offset, int len)
+{
+        /* Skip over the finished iovecs */
+        while (offset >= iov->iov_len) {
+                offset -= iov->iov_len;
+                iov++;
+        }
+
+        while (len > 0) {
+                u8 __user *base = iov->iov_base + offset;
+                int copy = min_t(unsigned int, len, iov->iov_len - offset);
+
+                offset = 0;
+                if (copy_from_user(kdata, base, copy))
+                        return -EFAULT;
+                len -= copy;
+                kdata += copy;
+                iov++;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(memcpy_fromiovecend);