diff options
| -rw-r--r-- | include/linux/uio.h | 1 | ||||
| -rw-r--r-- | lib/iov_iter.c | 26 |
2 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/uio.h b/include/linux/uio.h index 71880299ed48..a69ed25af07f 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -76,6 +76,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes); void iov_iter_advance(struct iov_iter *i, size_t bytes); int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); +int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes); size_t iov_iter_single_seg_count(const struct iov_iter *i); size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 9d96e283520c..b80f84376b91 100644 --- 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) |