Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[firefly-linux-kernel-4.4.55.git] / lib / iov_iter.c

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index fc6e33f6b7f3376b365c1b04409eb23580b729e2..75232ad0a5e7ead00e5d8396ed34763d84a0685c 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -317,6 +317,32 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
 }
 EXPORT_SYMBOL(iov_iter_fault_in_readable);
 
+/*
+ * Fault in one or more iovecs of the given iov_iter, to a maximum length of
+ * bytes.  For each iovec, fault in each page that constitutes the iovec.
+ *
+ * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
+ * because it is an invalid address).
+ */
+int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes)
+{
+       size_t skip = i->iov_offset;
+       const struct iovec *iov;
+       int err;
+       struct iovec v;
+
+       if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
+               iterate_iovec(i, bytes, v, iov, skip, ({
+                       err = fault_in_multipages_readable(v.iov_base,
+                                       v.iov_len);
+                       if (unlikely(err))
+                       return err;
+               0;}))
+       }
+       return 0;
+}
+EXPORT_SYMBOL(iov_iter_fault_in_multipages_readable);
+
 void iov_iter_init(struct iov_iter *i, int direction,
                        const struct iovec *iov, unsigned long nr_segs,
                        size_t count)