1 // SPDX-License-Identifier: GPL-2.0-or-later
17  * netfs_extract_user_iter - Extract the pages from a user iterator into a bvec
20  * @new: The iterator to be set up
24  * build up a second iterator that refers to all of those bits.  This allows
27  * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be
47 	size_t count = orig_len, offset, len;  in netfs_extract_user_iter()  local
51 		return -EIO;  in netfs_extract_user_iter()
57 		return -ENOMEM;  in netfs_extract_user_iter()
61 	 * 0->last, we should be fine.  in netfs_extract_user_iter()
64 	pages = (void *)bv + bv_size - pg_size;  in netfs_extract_user_iter()
66 	while (count && npages < max_pages) {  in netfs_extract_user_iter()
67 		ret = iov_iter_extract_pages(orig, &pages, count,  in netfs_extract_user_iter()
68 					     max_pages - npages, extraction_flags,  in netfs_extract_user_iter()
71 			ret = ret ?: -EIO;  in netfs_extract_user_iter()
75 		if (WARN(ret > count,  in netfs_extract_user_iter()
77 			 __func__, ret, count)) {  in netfs_extract_user_iter()
78 			ret = -EIO;  in netfs_extract_user_iter()
83 		if (WARN(cur_npages > max_pages - npages,  in netfs_extract_user_iter()
86 			ret = -EIO;  in netfs_extract_user_iter()
90 		count -= ret;  in netfs_extract_user_iter()
95 			bvec_set_page(bv + npages + i, *pages++, len - offset, offset);  in netfs_extract_user_iter()
96 			ret -= len;  in netfs_extract_user_iter()
103 	/* Note: Don't try to clean up after EIO.  Either we got no pages, so  in netfs_extract_user_iter()
104 	 * nothing to clean up, or we got a buffer overrun, memory corruption  in netfs_extract_user_iter()
108 	if (ret < 0 && (ret == -ENOMEM || npages == 0)) {  in netfs_extract_user_iter()
115 	iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count);  in netfs_extract_user_iter()
127 	const struct bio_vec *bvecs = iter->bvec;  in netfs_limit_bvec()
128 	unsigned int nbv = iter->nr_segs, ix = 0, nsegs = 0;  in netfs_limit_bvec()
129 	size_t len, span = 0, n = iter->count;  in netfs_limit_bvec()
130 	size_t skip = iter->iov_offset + start_offset;  in netfs_limit_bvec()
141 		skip -= len;  in netfs_limit_bvec()
142 		n -= len;  in netfs_limit_bvec()
147 		len = min3(n, bvecs[ix].bv_len - skip, max_size);  in netfs_limit_bvec()
154 		n -= len;  in netfs_limit_bvec()
168 	const struct kvec *kvecs = iter->kvec;  in netfs_limit_kvec()
169 	unsigned int nkv = iter->nr_segs, ix = 0, nsegs = 0;  in netfs_limit_kvec()
170 	size_t len, span = 0, n = iter->count;  in netfs_limit_kvec()
171 	size_t skip = iter->iov_offset + start_offset;  in netfs_limit_kvec()
182 		skip -= len;  in netfs_limit_kvec()
183 		n -= len;  in netfs_limit_kvec()
188 		len = min3(n, kvecs[ix].iov_len - skip, max_size);  in netfs_limit_kvec()
195 		n -= len;  in netfs_limit_kvec()
212 	loff_t pos = iter->xarray_start + iter->iov_offset;  in netfs_limit_xarray()
214 	size_t span = 0, n = iter->count;  in netfs_limit_xarray()
216 	XA_STATE(xas, iter->xarray, index);  in netfs_limit_xarray()
222 	max_size = min(max_size, n - start_offset);  in netfs_limit_xarray()
236 		len = min(max_size, flen - offset);  in netfs_limit_xarray()
255 	const struct folio_queue *folioq = iter->folioq;  in netfs_limit_folioq()
257 	unsigned int slot = iter->folioq_slot;  in netfs_limit_folioq()
258 	size_t span = 0, n = iter->count;  in netfs_limit_folioq()
264 	max_size = umin(max_size, n - start_offset);  in netfs_limit_folioq()
267 		folioq = folioq->next;  in netfs_limit_folioq()
271 	start_offset += iter->iov_offset;  in netfs_limit_folioq()
276 			span += flen - start_offset;  in netfs_limit_folioq()
280 			start_offset -= flen;  in netfs_limit_folioq()
287 			folioq = folioq->next;  in netfs_limit_folioq()