saner iov_iter initialization primitives

[mirror_ubuntu-artful-kernel.git] / lib / iov_iter.c

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 9d96e283520cc7f3ec27714dfa4abfcb3800e319..fc6e33f6b7f3376b365c1b04409eb23580b729e2 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -766,3 +766,60 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
                                   flags);
 }
 EXPORT_SYMBOL(dup_iter);
+
+int import_iovec(int type, const struct iovec __user * uvector,
+                unsigned nr_segs, unsigned fast_segs,
+                struct iovec **iov, struct iov_iter *i)
+{
+       ssize_t n;
+       struct iovec *p;
+       n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
+                                 *iov, &p);
+       if (n < 0) {
+               if (p != *iov)
+                       kfree(p);
+               *iov = NULL;
+               return n;
+       }
+       iov_iter_init(i, type, p, nr_segs, n);
+       *iov = p == *iov ? NULL : p;
+       return 0;
+}
+EXPORT_SYMBOL(import_iovec);
+
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
+                unsigned nr_segs, unsigned fast_segs,
+                struct iovec **iov, struct iov_iter *i)
+{
+       ssize_t n;
+       struct iovec *p;
+       n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
+                                 *iov, &p);
+       if (n < 0) {
+               if (p != *iov)
+                       kfree(p);
+               *iov = NULL;
+               return n;
+       }
+       iov_iter_init(i, type, p, nr_segs, n);
+       *iov = p == *iov ? NULL : p;
+       return 0;
+}
+#endif
+
+int import_single_range(int rw, void __user *buf, size_t len,
+                struct iovec *iov, struct iov_iter *i)
+{
+       if (len > MAX_RW_COUNT)
+               len = MAX_RW_COUNT;
+       if (unlikely(!access_ok(!rw, buf, len)))
+               return -EFAULT;
+
+       iov->iov_base = buf;
+       iov->iov_len = len;
+       iov_iter_init(i, rw, iov, 1, len);
+       return 0;
+}