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-rw-r--r--lib/iovec.c55
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);