Hoist memcpy_fromiovec/memcpy_toiovec into lib/

[~andy/linux] / lib / iovec.c

diff --git a/lib/iovec.c b/lib/iovec.c
new file mode 100644 (file)
index 0000000..454baa8
--- /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);