1 /* SPDX-License-Identifier: GPL-2.0 */
14 #include "highmem-internal.h"
17  * kmap - Map a page for long term usage
40  * kunmap - Unmap the virtual address mapped by kmap()
49  * kmap_to_page - Get the page for a kmap'ed address
57  * kmap_flush_unused - Flush all unused kmap mappings in order to
63  * kmap_local_page - Map a page for temporary usage
99  * kmap_local_folio - Map a page in this folio for temporary usage
101  * @offset: The byte offset within the folio which identifies the page.
135  * kmap_atomic - Atomically map a page for temporary usage - Deprecated!
212  * vma_alloc_zeroed_movable_folio - Allocate a zeroed page for a VMA.
231 		clear_user_highpage(&folio->page, vaddr);  in vma_alloc_zeroed_movable_folio()
278 		memset(kaddr + start1, 0, end1 - start1);  in zero_user_segments()
281 		memset(kaddr + start2, 0, end2 - start2);  in zero_user_segments()
396 			       size_t len)  in memcpy_page()  argument
401 	VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);  in memcpy_page()
402 	memcpy(dst + dst_off, src + src_off, len);  in memcpy_page()
408 			       size_t len)  in memset_page()  argument
412 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memset_page()
413 	memset(addr + offset, val, len);  in memset_page()
418 				    size_t offset, size_t len)  in memcpy_from_page()  argument
422 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memcpy_from_page()
423 	memcpy(to, from + offset, len);  in memcpy_from_page()
428 				  const char *from, size_t len)  in memcpy_to_page()  argument
432 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memcpy_to_page()
433 	memcpy(to + offset, from, len);  in memcpy_to_page()
438 static inline void memzero_page(struct page *page, size_t offset, size_t len)  in memzero_page()  argument
442 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memzero_page()
443 	memset(addr + offset, 0, len);  in memzero_page()
449  * memcpy_from_folio - Copy a range of bytes from a folio.
452  * @offset: The first byte in the folio to read.
453  * @len: The number of bytes to copy.
456 		size_t offset, size_t len)  in memcpy_from_folio()  argument
458 	VM_BUG_ON(offset + len > folio_size(folio));  in memcpy_from_folio()
462 		size_t chunk = len;  in memcpy_from_folio()
465 		    chunk > PAGE_SIZE - offset_in_page(offset))  in memcpy_from_folio()
466 			chunk = PAGE_SIZE - offset_in_page(offset);  in memcpy_from_folio()
472 		len -= chunk;  in memcpy_from_folio()
473 	} while (len > 0);  in memcpy_from_folio()
477  * memcpy_to_folio - Copy a range of bytes to a folio.
479  * @offset: The first byte in the folio to store to.
481  * @len: The number of bytes to copy.
484 		const char *from, size_t len)  in memcpy_to_folio()  argument
486 	VM_BUG_ON(offset + len > folio_size(folio));  in memcpy_to_folio()
490 		size_t chunk = len;  in memcpy_to_folio()
493 		    chunk > PAGE_SIZE - offset_in_page(offset))  in memcpy_to_folio()
494 			chunk = PAGE_SIZE - offset_in_page(offset);  in memcpy_to_folio()
500 		len -= chunk;  in memcpy_to_folio()
501 	} while (len > 0);  in memcpy_to_folio()
507  * folio_zero_tail - Zero the tail of a folio.
509  * @offset: The byte offset in the folio to start zeroing at.
523 	size_t len = folio_size(folio) - offset;  in folio_zero_tail()  local
526 		size_t max = PAGE_SIZE - offset_in_page(offset);  in folio_zero_tail()
528 		while (len > max) {  in folio_zero_tail()
531 			len -= max;  in folio_zero_tail()
538 	memset(kaddr, 0, len);  in folio_zero_tail()
545  * folio_fill_tail - Copy some data to a folio and pad with zeroes.
549  * @len: How many bytes of data to copy.
557 		const char *from, size_t len)  in folio_fill_tail()  argument
561 	VM_BUG_ON(offset + len > folio_size(folio));  in folio_fill_tail()
564 		size_t max = PAGE_SIZE - offset_in_page(offset);  in folio_fill_tail()
566 		while (len > max) {  in folio_fill_tail()
569 			len -= max;  in folio_fill_tail()
577 	memcpy(to, from, len);  in folio_fill_tail()
578 	to = folio_zero_tail(folio, offset + len, to + len);  in folio_fill_tail()
583  * memcpy_from_file_folio - Copy some bytes from a file folio.
587  * @len: The maximum number of bytes to copy.
589  * Copy up to @len bytes from this folio.  This may be limited by PAGE_SIZE
595 		loff_t pos, size_t len)  in memcpy_from_file_folio()  argument
602 		len = min_t(size_t, len, PAGE_SIZE - offset);  in memcpy_from_file_folio()
604 		len = min(len, folio_size(folio) - offset);  in memcpy_from_file_folio()
606 	memcpy(to, from, len);  in memcpy_from_file_folio()
609 	return len;  in memcpy_from_file_folio()
613  * folio_zero_segments() - Zero two byte ranges in a folio.
615  * @start1: The first byte to zero.
616  * @xend1: One more than the last byte in the first range.
617  * @start2: The first byte to zero in the second range.
618  * @xend2: One more than the last byte in the second range.
623 	zero_user_segments(&folio->page, start1, xend1, start2, xend2);  in folio_zero_segments()
627  * folio_zero_segment() - Zero a byte range in a folio.
629  * @start: The first byte to zero.
630  * @xend: One more than the last byte to zero.
635 	zero_user_segments(&folio->page, start, xend, 0, 0);  in folio_zero_segment()
639  * folio_zero_range() - Zero a byte range in a folio.
641  * @start: The first byte to zero.
647 	zero_user_segments(&folio->page, start, start + length, 0, 0);  in folio_zero_range()
651  * folio_release_kmap - Unmap a folio and drop a refcount.