2 files changed, 54 insertions, 1 deletions

diff --git a/lib/Makefile b/lib/Makefile
index e9c52e1b853a..c55a037a354e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -23,7 +23,7 @@ lib-y	+= kobject.o klist.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
          bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
-         gcd.o lcm.o list_sort.o uuid.o flex_array.o \
+         gcd.o lcm.o list_sort.o uuid.o flex_array.o iovec.o \
          bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o
 obj-y += string_helpers.o
 obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
diff --git a/lib/iovec.c b/lib/iovec.c
new file mode 100644
index 000000000000..454baa88bf27
--- /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);