-/*
- * Performs necessary checks before doing a write
- * @iov: io vector request
- * @nr_segs: number of segments in the iovec
- * @count: number of bytes to write
- * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE
- *
- * Adjust number of segments and amount of bytes to write (nr_segs should be
- * properly initialized first). Returns appropriate error code that caller
- * should return or zero in case that write should be allowed.
- */
-int generic_segment_checks(const struct iovec *iov,
- unsigned long *nr_segs, size_t *count, int access_flags)
-{
- unsigned long seg;
- size_t cnt = 0;
- for (seg = 0; seg < *nr_segs; seg++) {
- const struct iovec *iv = &iov[seg];
-
- /*
- * If any segment has a negative length, or the cumulative
- * length ever wraps negative then return -EINVAL.
- */
- cnt += iv->iov_len;
- if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))
- return -EINVAL;
- if (access_ok(access_flags, iv->iov_base, iv->iov_len))
- continue;
- if (seg == 0)
- return -EFAULT;
- *nr_segs = seg;
- cnt -= iv->iov_len; /* This segment is no good */
- break;
- }
- *count = cnt;
- return 0;
-}
-EXPORT_SYMBOL(generic_segment_checks);
-