2 * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com>
4 * Scatterlist handling helpers.
6 * This source code is licensed under the GNU General Public License,
7 * Version 2. See the file COPYING for more details.
9 #include <linux/export.h>
10 #include <linux/slab.h>
11 #include <linux/scatterlist.h>
12 #include <linux/highmem.h>
13 #include <linux/kmemleak.h>
16 * sg_next - return the next scatterlist entry in a list
17 * @sg: The current sg entry
20 * Usually the next entry will be @sg@ + 1, but if this sg element is part
21 * of a chained scatterlist, it could jump to the start of a new
25 struct scatterlist *sg_next(struct scatterlist *sg)
31 if (unlikely(sg_is_chain(sg)))
32 sg = sg_chain_ptr(sg);
36 EXPORT_SYMBOL(sg_next);
39 * sg_nents - return total count of entries in scatterlist
40 * @sg: The scatterlist
43 * Allows to know how many entries are in sg, taking into acount
47 int sg_nents(struct scatterlist *sg)
50 for (nents = 0; sg; sg = sg_next(sg))
54 EXPORT_SYMBOL(sg_nents);
57 * sg_nents_for_len - return total count of entries in scatterlist
58 * needed to satisfy the supplied length
59 * @sg: The scatterlist
60 * @len: The total required length
63 * Determines the number of entries in sg that are required to meet
64 * the supplied length, taking into acount chaining as well
67 * the number of sg entries needed, negative error on failure
70 int sg_nents_for_len(struct scatterlist *sg, u64 len)
78 for (nents = 0, total = 0; sg; sg = sg_next(sg)) {
87 EXPORT_SYMBOL(sg_nents_for_len);
90 * sg_last - return the last scatterlist entry in a list
91 * @sgl: First entry in the scatterlist
92 * @nents: Number of entries in the scatterlist
95 * Should only be used casually, it (currently) scans the entire list
96 * to get the last entry.
98 * Note that the @sgl@ pointer passed in need not be the first one,
99 * the important bit is that @nents@ denotes the number of entries that
103 struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents)
105 struct scatterlist *sg, *ret = NULL;
108 for_each_sg(sgl, sg, nents, i)
111 BUG_ON(!sg_is_last(ret));
114 EXPORT_SYMBOL(sg_last);
117 * sg_init_table - Initialize SG table
119 * @nents: Number of entries in table
122 * If this is part of a chained sg table, sg_mark_end() should be
123 * used only on the last table part.
126 void sg_init_table(struct scatterlist *sgl, unsigned int nents)
128 memset(sgl, 0, sizeof(*sgl) * nents);
129 sg_init_marker(sgl, nents);
131 EXPORT_SYMBOL(sg_init_table);
134 * sg_init_one - Initialize a single entry sg list
136 * @buf: Virtual address for IO
140 void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen)
142 sg_init_table(sg, 1);
143 sg_set_buf(sg, buf, buflen);
145 EXPORT_SYMBOL(sg_init_one);
148 * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree
151 static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask)
153 if (nents == SG_MAX_SINGLE_ALLOC) {
155 * Kmemleak doesn't track page allocations as they are not
156 * commonly used (in a raw form) for kernel data structures.
157 * As we chain together a list of pages and then a normal
158 * kmalloc (tracked by kmemleak), in order to for that last
159 * allocation not to become decoupled (and thus a
160 * false-positive) we need to inform kmemleak of all the
161 * intermediate allocations.
163 void *ptr = (void *) __get_free_page(gfp_mask);
164 kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask);
167 return kmalloc(nents * sizeof(struct scatterlist), gfp_mask);
170 static void sg_kfree(struct scatterlist *sg, unsigned int nents)
172 if (nents == SG_MAX_SINGLE_ALLOC) {
174 free_page((unsigned long) sg);
180 * __sg_free_table - Free a previously mapped sg table
181 * @table: The sg table header to use
182 * @max_ents: The maximum number of entries per single scatterlist
183 * @skip_first_chunk: don't free the (preallocated) first scatterlist chunk
184 * @free_fn: Free function
187 * Free an sg table previously allocated and setup with
188 * __sg_alloc_table(). The @max_ents value must be identical to
189 * that previously used with __sg_alloc_table().
192 void __sg_free_table(struct sg_table *table, unsigned int max_ents,
193 bool skip_first_chunk, sg_free_fn *free_fn)
195 struct scatterlist *sgl, *next;
197 if (unlikely(!table->sgl))
201 while (table->orig_nents) {
202 unsigned int alloc_size = table->orig_nents;
203 unsigned int sg_size;
206 * If we have more than max_ents segments left,
207 * then assign 'next' to the sg table after the current one.
208 * sg_size is then one less than alloc size, since the last
209 * element is the chain pointer.
211 if (alloc_size > max_ents) {
212 next = sg_chain_ptr(&sgl[max_ents - 1]);
213 alloc_size = max_ents;
214 sg_size = alloc_size - 1;
216 sg_size = alloc_size;
220 table->orig_nents -= sg_size;
221 if (skip_first_chunk)
222 skip_first_chunk = false;
224 free_fn(sgl, alloc_size);
230 EXPORT_SYMBOL(__sg_free_table);
233 * sg_free_table - Free a previously allocated sg table
234 * @table: The mapped sg table header
237 void sg_free_table(struct sg_table *table)
239 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
241 EXPORT_SYMBOL(sg_free_table);
244 * __sg_alloc_table - Allocate and initialize an sg table with given allocator
245 * @table: The sg table header to use
246 * @nents: Number of entries in sg list
247 * @max_ents: The maximum number of entries the allocator returns per call
248 * @gfp_mask: GFP allocation mask
249 * @alloc_fn: Allocator to use
252 * This function returns a @table @nents long. The allocator is
253 * defined to return scatterlist chunks of maximum size @max_ents.
254 * Thus if @nents is bigger than @max_ents, the scatterlists will be
255 * chained in units of @max_ents.
258 * If this function returns non-0 (eg failure), the caller must call
259 * __sg_free_table() to cleanup any leftover allocations.
262 int __sg_alloc_table(struct sg_table *table, unsigned int nents,
263 unsigned int max_ents, struct scatterlist *first_chunk,
264 gfp_t gfp_mask, sg_alloc_fn *alloc_fn)
266 struct scatterlist *sg, *prv;
269 memset(table, 0, sizeof(*table));
273 #ifndef CONFIG_ARCH_HAS_SG_CHAIN
274 if (WARN_ON_ONCE(nents > max_ents))
281 unsigned int sg_size, alloc_size = left;
283 if (alloc_size > max_ents) {
284 alloc_size = max_ents;
285 sg_size = alloc_size - 1;
287 sg_size = alloc_size;
295 sg = alloc_fn(alloc_size, gfp_mask);
299 * Adjust entry count to reflect that the last
300 * entry of the previous table won't be used for
301 * linkage. Without this, sg_kfree() may get
305 table->nents = ++table->orig_nents;
310 sg_init_table(sg, alloc_size);
311 table->nents = table->orig_nents += sg_size;
314 * If this is the first mapping, assign the sg table header.
315 * If this is not the first mapping, chain previous part.
318 sg_chain(prv, max_ents, sg);
323 * If no more entries after this one, mark the end
326 sg_mark_end(&sg[sg_size - 1]);
333 EXPORT_SYMBOL(__sg_alloc_table);
336 * sg_alloc_table - Allocate and initialize an sg table
337 * @table: The sg table header to use
338 * @nents: Number of entries in sg list
339 * @gfp_mask: GFP allocation mask
342 * Allocate and initialize an sg table. If @nents@ is larger than
343 * SG_MAX_SINGLE_ALLOC a chained sg table will be setup.
346 int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
350 ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
351 NULL, gfp_mask, sg_kmalloc);
353 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
357 EXPORT_SYMBOL(sg_alloc_table);
360 * __sg_alloc_table_from_pages - Allocate and initialize an sg table from
362 * @sgt: The sg table header to use
363 * @pages: Pointer to an array of page pointers
364 * @n_pages: Number of pages in the pages array
365 * @offset: Offset from start of the first page to the start of a buffer
366 * @size: Number of valid bytes in the buffer (after offset)
367 * @max_segment: Maximum size of a scatterlist node in bytes (page aligned)
368 * @gfp_mask: GFP allocation mask
371 * Allocate and initialize an sg table from a list of pages. Contiguous
372 * ranges of the pages are squashed into a single scatterlist node up to the
373 * maximum size specified in @max_segment. An user may provide an offset at a
374 * start and a size of valid data in a buffer specified by the page array.
375 * The returned sg table is released by sg_free_table.
378 * 0 on success, negative error on failure
380 int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
381 unsigned int n_pages, unsigned int offset,
382 unsigned long size, unsigned int max_segment,
385 unsigned int chunks, cur_page, seg_len, i;
387 struct scatterlist *s;
389 if (WARN_ON(!max_segment || offset_in_page(max_segment)))
392 /* compute number of contiguous chunks */
395 for (i = 1; i < n_pages; i++) {
396 seg_len += PAGE_SIZE;
397 if (seg_len >= max_segment ||
398 page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) {
404 ret = sg_alloc_table(sgt, chunks, gfp_mask);
408 /* merging chunks and putting them into the scatterlist */
410 for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
411 unsigned int j, chunk_size;
413 /* look for the end of the current chunk */
415 for (j = cur_page + 1; j < n_pages; j++) {
416 seg_len += PAGE_SIZE;
417 if (seg_len >= max_segment ||
418 page_to_pfn(pages[j]) !=
419 page_to_pfn(pages[j - 1]) + 1)
423 chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset;
424 sg_set_page(s, pages[cur_page],
425 min_t(unsigned long, size, chunk_size), offset);
433 EXPORT_SYMBOL(__sg_alloc_table_from_pages);
436 * sg_alloc_table_from_pages - Allocate and initialize an sg table from
438 * @sgt: The sg table header to use
439 * @pages: Pointer to an array of page pointers
440 * @n_pages: Number of pages in the pages array
441 * @offset: Offset from start of the first page to the start of a buffer
442 * @size: Number of valid bytes in the buffer (after offset)
443 * @gfp_mask: GFP allocation mask
446 * Allocate and initialize an sg table from a list of pages. Contiguous
447 * ranges of the pages are squashed into a single scatterlist node. A user
448 * may provide an offset at a start and a size of valid data in a buffer
449 * specified by the page array. The returned sg table is released by
453 * 0 on success, negative error on failure
455 int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
456 unsigned int n_pages, unsigned int offset,
457 unsigned long size, gfp_t gfp_mask)
459 return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size,
460 SCATTERLIST_MAX_SEGMENT, gfp_mask);
462 EXPORT_SYMBOL(sg_alloc_table_from_pages);
464 #ifdef CONFIG_SGL_ALLOC
467 * sgl_alloc_order - allocate a scatterlist and its pages
468 * @length: Length in bytes of the scatterlist. Must be at least one
469 * @order: Second argument for alloc_pages()
470 * @chainable: Whether or not to allocate an extra element in the scatterlist
471 * for scatterlist chaining purposes
472 * @gfp: Memory allocation flags
473 * @nent_p: [out] Number of entries in the scatterlist that have pages
475 * Returns: A pointer to an initialized scatterlist or %NULL upon failure.
477 struct scatterlist *sgl_alloc_order(unsigned long long length,
478 unsigned int order, bool chainable,
479 gfp_t gfp, unsigned int *nent_p)
481 struct scatterlist *sgl, *sg;
483 unsigned int nent, nalloc;
486 nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order);
487 /* Check for integer overflow */
488 if (length > (nent << (PAGE_SHIFT + order)))
492 /* Check for integer overflow */
493 if (nalloc + 1 < nalloc)
497 sgl = kmalloc_array(nalloc, sizeof(struct scatterlist),
498 (gfp & ~GFP_DMA) | __GFP_ZERO);
502 sg_init_table(sgl, nalloc);
505 elem_len = min_t(u64, length, PAGE_SIZE << order);
506 page = alloc_pages(gfp, order);
512 sg_set_page(sg, page, elem_len, 0);
516 WARN_ONCE(length, "length = %lld\n", length);
521 EXPORT_SYMBOL(sgl_alloc_order);
524 * sgl_alloc - allocate a scatterlist and its pages
525 * @length: Length in bytes of the scatterlist
526 * @gfp: Memory allocation flags
527 * @nent_p: [out] Number of entries in the scatterlist
529 * Returns: A pointer to an initialized scatterlist or %NULL upon failure.
531 struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp,
532 unsigned int *nent_p)
534 return sgl_alloc_order(length, 0, false, gfp, nent_p);
536 EXPORT_SYMBOL(sgl_alloc);
539 * sgl_free_n_order - free a scatterlist and its pages
540 * @sgl: Scatterlist with one or more elements
541 * @nents: Maximum number of elements to free
542 * @order: Second argument for __free_pages()
545 * - If several scatterlists have been chained and each chain element is
546 * freed separately then it's essential to set nents correctly to avoid that a
547 * page would get freed twice.
548 * - All pages in a chained scatterlist can be freed at once by setting @nents
551 void sgl_free_n_order(struct scatterlist *sgl, int nents, int order)
553 struct scatterlist *sg;
557 for_each_sg(sgl, sg, nents, i) {
562 __free_pages(page, order);
566 EXPORT_SYMBOL(sgl_free_n_order);
569 * sgl_free_order - free a scatterlist and its pages
570 * @sgl: Scatterlist with one or more elements
571 * @order: Second argument for __free_pages()
573 void sgl_free_order(struct scatterlist *sgl, int order)
575 sgl_free_n_order(sgl, INT_MAX, order);
577 EXPORT_SYMBOL(sgl_free_order);
580 * sgl_free - free a scatterlist and its pages
581 * @sgl: Scatterlist with one or more elements
583 void sgl_free(struct scatterlist *sgl)
585 sgl_free_order(sgl, 0);
587 EXPORT_SYMBOL(sgl_free);
589 #endif /* CONFIG_SGL_ALLOC */
591 void __sg_page_iter_start(struct sg_page_iter *piter,
592 struct scatterlist *sglist, unsigned int nents,
593 unsigned long pgoffset)
595 piter->__pg_advance = 0;
596 piter->__nents = nents;
599 piter->sg_pgoffset = pgoffset;
601 EXPORT_SYMBOL(__sg_page_iter_start);
603 static int sg_page_count(struct scatterlist *sg)
605 return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT;
608 bool __sg_page_iter_next(struct sg_page_iter *piter)
610 if (!piter->__nents || !piter->sg)
613 piter->sg_pgoffset += piter->__pg_advance;
614 piter->__pg_advance = 1;
616 while (piter->sg_pgoffset >= sg_page_count(piter->sg)) {
617 piter->sg_pgoffset -= sg_page_count(piter->sg);
618 piter->sg = sg_next(piter->sg);
619 if (!--piter->__nents || !piter->sg)
625 EXPORT_SYMBOL(__sg_page_iter_next);
628 * sg_miter_start - start mapping iteration over a sg list
629 * @miter: sg mapping iter to be started
630 * @sgl: sg list to iterate over
631 * @nents: number of sg entries
634 * Starts mapping iterator @miter.
639 void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,
640 unsigned int nents, unsigned int flags)
642 memset(miter, 0, sizeof(struct sg_mapping_iter));
644 __sg_page_iter_start(&miter->piter, sgl, nents, 0);
645 WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG)));
646 miter->__flags = flags;
648 EXPORT_SYMBOL(sg_miter_start);
650 static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)
652 if (!miter->__remaining) {
653 struct scatterlist *sg;
654 unsigned long pgoffset;
656 if (!__sg_page_iter_next(&miter->piter))
659 sg = miter->piter.sg;
660 pgoffset = miter->piter.sg_pgoffset;
662 miter->__offset = pgoffset ? 0 : sg->offset;
663 miter->__remaining = sg->offset + sg->length -
664 (pgoffset << PAGE_SHIFT) - miter->__offset;
665 miter->__remaining = min_t(unsigned long, miter->__remaining,
666 PAGE_SIZE - miter->__offset);
673 * sg_miter_skip - reposition mapping iterator
674 * @miter: sg mapping iter to be skipped
675 * @offset: number of bytes to plus the current location
678 * Sets the offset of @miter to its current location plus @offset bytes.
679 * If mapping iterator @miter has been proceeded by sg_miter_next(), this
683 * Don't care if @miter is stopped, or not proceeded yet.
684 * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set.
687 * true if @miter contains the valid mapping. false if end of sg
690 bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)
692 sg_miter_stop(miter);
697 if (!sg_miter_get_next_page(miter))
700 consumed = min_t(off_t, offset, miter->__remaining);
701 miter->__offset += consumed;
702 miter->__remaining -= consumed;
708 EXPORT_SYMBOL(sg_miter_skip);
711 * sg_miter_next - proceed mapping iterator to the next mapping
712 * @miter: sg mapping iter to proceed
715 * Proceeds @miter to the next mapping. @miter should have been started
716 * using sg_miter_start(). On successful return, @miter->page,
717 * @miter->addr and @miter->length point to the current mapping.
720 * Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled
721 * till @miter is stopped. May sleep if !SG_MITER_ATOMIC.
724 * true if @miter contains the next mapping. false if end of sg
727 bool sg_miter_next(struct sg_mapping_iter *miter)
729 sg_miter_stop(miter);
732 * Get to the next page if necessary.
733 * __remaining, __offset is adjusted by sg_miter_stop
735 if (!sg_miter_get_next_page(miter))
738 miter->page = sg_page_iter_page(&miter->piter);
739 miter->consumed = miter->length = miter->__remaining;
741 if (miter->__flags & SG_MITER_ATOMIC)
742 miter->addr = kmap_atomic(miter->page) + miter->__offset;
744 miter->addr = kmap(miter->page) + miter->__offset;
748 EXPORT_SYMBOL(sg_miter_next);
751 * sg_miter_stop - stop mapping iteration
752 * @miter: sg mapping iter to be stopped
755 * Stops mapping iterator @miter. @miter should have been started
756 * using sg_miter_start(). A stopped iteration can be resumed by
757 * calling sg_miter_next() on it. This is useful when resources (kmap)
758 * need to be released during iteration.
761 * Preemption disabled if the SG_MITER_ATOMIC is set. Don't care
764 void sg_miter_stop(struct sg_mapping_iter *miter)
766 WARN_ON(miter->consumed > miter->length);
768 /* drop resources from the last iteration */
770 miter->__offset += miter->consumed;
771 miter->__remaining -= miter->consumed;
773 if ((miter->__flags & SG_MITER_TO_SG) &&
774 !PageSlab(miter->page))
775 flush_kernel_dcache_page(miter->page);
777 if (miter->__flags & SG_MITER_ATOMIC) {
778 WARN_ON_ONCE(preemptible());
779 kunmap_atomic(miter->addr);
789 EXPORT_SYMBOL(sg_miter_stop);
792 * sg_copy_buffer - Copy data between a linear buffer and an SG list
794 * @nents: Number of SG entries
795 * @buf: Where to copy from
796 * @buflen: The number of bytes to copy
797 * @skip: Number of bytes to skip before copying
798 * @to_buffer: transfer direction (true == from an sg list to a
799 * buffer, false == from a buffer to an sg list
801 * Returns the number of copied bytes.
804 size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
805 size_t buflen, off_t skip, bool to_buffer)
807 unsigned int offset = 0;
808 struct sg_mapping_iter miter;
809 unsigned int sg_flags = SG_MITER_ATOMIC;
812 sg_flags |= SG_MITER_FROM_SG;
814 sg_flags |= SG_MITER_TO_SG;
816 sg_miter_start(&miter, sgl, nents, sg_flags);
818 if (!sg_miter_skip(&miter, skip))
821 while ((offset < buflen) && sg_miter_next(&miter)) {
824 len = min(miter.length, buflen - offset);
827 memcpy(buf + offset, miter.addr, len);
829 memcpy(miter.addr, buf + offset, len);
834 sg_miter_stop(&miter);
838 EXPORT_SYMBOL(sg_copy_buffer);
841 * sg_copy_from_buffer - Copy from a linear buffer to an SG list
843 * @nents: Number of SG entries
844 * @buf: Where to copy from
845 * @buflen: The number of bytes to copy
847 * Returns the number of copied bytes.
850 size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
851 const void *buf, size_t buflen)
853 return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false);
855 EXPORT_SYMBOL(sg_copy_from_buffer);
858 * sg_copy_to_buffer - Copy from an SG list to a linear buffer
860 * @nents: Number of SG entries
861 * @buf: Where to copy to
862 * @buflen: The number of bytes to copy
864 * Returns the number of copied bytes.
867 size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
868 void *buf, size_t buflen)
870 return sg_copy_buffer(sgl, nents, buf, buflen, 0, true);
872 EXPORT_SYMBOL(sg_copy_to_buffer);
875 * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list
877 * @nents: Number of SG entries
878 * @buf: Where to copy from
879 * @buflen: The number of bytes to copy
880 * @skip: Number of bytes to skip before copying
882 * Returns the number of copied bytes.
885 size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
886 const void *buf, size_t buflen, off_t skip)
888 return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false);
890 EXPORT_SYMBOL(sg_pcopy_from_buffer);
893 * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer
895 * @nents: Number of SG entries
896 * @buf: Where to copy to
897 * @buflen: The number of bytes to copy
898 * @skip: Number of bytes to skip before copying
900 * Returns the number of copied bytes.
903 size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
904 void *buf, size_t buflen, off_t skip)
906 return sg_copy_buffer(sgl, nents, buf, buflen, skip, true);
908 EXPORT_SYMBOL(sg_pcopy_to_buffer);
911 * sg_zero_buffer - Zero-out a part of a SG list
913 * @nents: Number of SG entries
914 * @buflen: The number of bytes to zero out
915 * @skip: Number of bytes to skip before zeroing
917 * Returns the number of bytes zeroed.
919 size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
920 size_t buflen, off_t skip)
922 unsigned int offset = 0;
923 struct sg_mapping_iter miter;
924 unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
926 sg_miter_start(&miter, sgl, nents, sg_flags);
928 if (!sg_miter_skip(&miter, skip))
931 while (offset < buflen && sg_miter_next(&miter)) {
934 len = min(miter.length, buflen - offset);
935 memset(miter.addr, 0, len);
940 sg_miter_stop(&miter);
943 EXPORT_SYMBOL(sg_zero_buffer);