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lib/scatterlist.c
27.3 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com> * * Scatterlist handling helpers. |
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*/ |
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#include <linux/export.h> |
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#include <linux/slab.h> |
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#include <linux/scatterlist.h> |
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#include <linux/highmem.h> |
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#include <linux/kmemleak.h> |
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/** * sg_next - return the next scatterlist entry in a list * @sg: The current sg entry * * Description: * Usually the next entry will be @sg@ + 1, but if this sg element is part * of a chained scatterlist, it could jump to the start of a new * scatterlist array. * **/ struct scatterlist *sg_next(struct scatterlist *sg) { |
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if (sg_is_last(sg)) return NULL; sg++; if (unlikely(sg_is_chain(sg))) sg = sg_chain_ptr(sg); return sg; } EXPORT_SYMBOL(sg_next); /** |
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* sg_nents - return total count of entries in scatterlist * @sg: The scatterlist * * Description: * Allows to know how many entries are in sg, taking into acount * chaining as well * **/ int sg_nents(struct scatterlist *sg) { |
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int nents; for (nents = 0; sg; sg = sg_next(sg)) |
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nents++; |
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return nents; } EXPORT_SYMBOL(sg_nents); |
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/** * sg_nents_for_len - return total count of entries in scatterlist * needed to satisfy the supplied length * @sg: The scatterlist * @len: The total required length * * Description: * Determines the number of entries in sg that are required to meet * the supplied length, taking into acount chaining as well * * Returns: * the number of sg entries needed, negative error on failure * **/ int sg_nents_for_len(struct scatterlist *sg, u64 len) { int nents; u64 total; if (!len) return 0; for (nents = 0, total = 0; sg; sg = sg_next(sg)) { nents++; total += sg->length; if (total >= len) return nents; } return -EINVAL; } EXPORT_SYMBOL(sg_nents_for_len); |
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/** |
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* sg_last - return the last scatterlist entry in a list * @sgl: First entry in the scatterlist * @nents: Number of entries in the scatterlist * * Description: * Should only be used casually, it (currently) scans the entire list * to get the last entry. * * Note that the @sgl@ pointer passed in need not be the first one, * the important bit is that @nents@ denotes the number of entries that * exist from @sgl@. * **/ struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) { |
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struct scatterlist *sg, *ret = NULL; unsigned int i; for_each_sg(sgl, sg, nents, i) ret = sg; |
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BUG_ON(!sg_is_last(ret)); |
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return ret; } EXPORT_SYMBOL(sg_last); /** * sg_init_table - Initialize SG table * @sgl: The SG table * @nents: Number of entries in table * * Notes: * If this is part of a chained sg table, sg_mark_end() should be * used only on the last table part. * **/ void sg_init_table(struct scatterlist *sgl, unsigned int nents) { memset(sgl, 0, sizeof(*sgl) * nents); |
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sg_init_marker(sgl, nents); |
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} EXPORT_SYMBOL(sg_init_table); /** * sg_init_one - Initialize a single entry sg list * @sg: SG entry * @buf: Virtual address for IO * @buflen: IO length * **/ void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) { sg_init_table(sg, 1); sg_set_buf(sg, buf, buflen); } EXPORT_SYMBOL(sg_init_one); /* * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree * helpers. */ static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) { |
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if (nents == SG_MAX_SINGLE_ALLOC) { /* * Kmemleak doesn't track page allocations as they are not * commonly used (in a raw form) for kernel data structures. * As we chain together a list of pages and then a normal * kmalloc (tracked by kmemleak), in order to for that last * allocation not to become decoupled (and thus a * false-positive) we need to inform kmemleak of all the * intermediate allocations. */ void *ptr = (void *) __get_free_page(gfp_mask); kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask); return ptr; } else |
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return kmalloc_array(nents, sizeof(struct scatterlist), gfp_mask); |
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} static void sg_kfree(struct scatterlist *sg, unsigned int nents) { |
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if (nents == SG_MAX_SINGLE_ALLOC) { kmemleak_free(sg); |
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free_page((unsigned long) sg); |
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} else |
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kfree(sg); } /** * __sg_free_table - Free a previously mapped sg table * @table: The sg table header to use |
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* @max_ents: The maximum number of entries per single scatterlist |
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* @nents_first_chunk: Number of entries int the (preallocated) first * scatterlist chunk, 0 means no such preallocated first chunk |
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* @free_fn: Free function * * Description: |
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* Free an sg table previously allocated and setup with * __sg_alloc_table(). The @max_ents value must be identical to * that previously used with __sg_alloc_table(). |
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* **/ |
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void __sg_free_table(struct sg_table *table, unsigned int max_ents, |
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unsigned int nents_first_chunk, sg_free_fn *free_fn) |
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{ struct scatterlist *sgl, *next; |
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unsigned curr_max_ents = nents_first_chunk ?: max_ents; |
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if (unlikely(!table->sgl)) return; sgl = table->sgl; while (table->orig_nents) { unsigned int alloc_size = table->orig_nents; unsigned int sg_size; /* |
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* If we have more than max_ents segments left, |
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* then assign 'next' to the sg table after the current one. * sg_size is then one less than alloc size, since the last * element is the chain pointer. */ |
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if (alloc_size > curr_max_ents) { next = sg_chain_ptr(&sgl[curr_max_ents - 1]); alloc_size = curr_max_ents; |
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sg_size = alloc_size - 1; } else { sg_size = alloc_size; next = NULL; } table->orig_nents -= sg_size; |
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if (nents_first_chunk) nents_first_chunk = 0; |
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else free_fn(sgl, alloc_size); |
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sgl = next; |
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curr_max_ents = max_ents; |
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} table->sgl = NULL; } EXPORT_SYMBOL(__sg_free_table); /** * sg_free_table - Free a previously allocated sg table * @table: The mapped sg table header * **/ void sg_free_table(struct sg_table *table) { |
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__sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree); |
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} EXPORT_SYMBOL(sg_free_table); /** * __sg_alloc_table - Allocate and initialize an sg table with given allocator * @table: The sg table header to use * @nents: Number of entries in sg list |
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* @max_ents: The maximum number of entries the allocator returns per call |
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* @nents_first_chunk: Number of entries int the (preallocated) first * scatterlist chunk, 0 means no such preallocated chunk provided by user |
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* @gfp_mask: GFP allocation mask * @alloc_fn: Allocator to use * |
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* Description: * This function returns a @table @nents long. The allocator is * defined to return scatterlist chunks of maximum size @max_ents. * Thus if @nents is bigger than @max_ents, the scatterlists will be * chained in units of @max_ents. * |
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* Notes: * If this function returns non-0 (eg failure), the caller must call * __sg_free_table() to cleanup any leftover allocations. * **/ |
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int __sg_alloc_table(struct sg_table *table, unsigned int nents, |
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unsigned int max_ents, struct scatterlist *first_chunk, |
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unsigned int nents_first_chunk, gfp_t gfp_mask, sg_alloc_fn *alloc_fn) |
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{ struct scatterlist *sg, *prv; unsigned int left; |
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unsigned curr_max_ents = nents_first_chunk ?: max_ents; unsigned prv_max_ents; |
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|
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memset(table, 0, sizeof(*table)); if (nents == 0) return -EINVAL; |
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#ifdef CONFIG_ARCH_NO_SG_CHAIN |
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if (WARN_ON_ONCE(nents > max_ents)) return -EINVAL; |
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#endif |
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left = nents; prv = NULL; do { unsigned int sg_size, alloc_size = left; |
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if (alloc_size > curr_max_ents) { alloc_size = curr_max_ents; |
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sg_size = alloc_size - 1; } else sg_size = alloc_size; left -= sg_size; |
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if (first_chunk) { sg = first_chunk; first_chunk = NULL; } else { sg = alloc_fn(alloc_size, gfp_mask); } |
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if (unlikely(!sg)) { /* * Adjust entry count to reflect that the last * entry of the previous table won't be used for * linkage. Without this, sg_kfree() may get * confused. */ if (prv) table->nents = ++table->orig_nents; |
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return -ENOMEM; |
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} |
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sg_init_table(sg, alloc_size); table->nents = table->orig_nents += sg_size; /* * If this is the first mapping, assign the sg table header. * If this is not the first mapping, chain previous part. */ if (prv) |
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sg_chain(prv, prv_max_ents, sg); |
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else table->sgl = sg; /* * If no more entries after this one, mark the end */ if (!left) sg_mark_end(&sg[sg_size - 1]); |
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prv = sg; |
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prv_max_ents = curr_max_ents; curr_max_ents = max_ents; |
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} while (left); return 0; } EXPORT_SYMBOL(__sg_alloc_table); /** * sg_alloc_table - Allocate and initialize an sg table * @table: The sg table header to use * @nents: Number of entries in sg list * @gfp_mask: GFP allocation mask * * Description: * Allocate and initialize an sg table. If @nents@ is larger than * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. * **/ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) { int ret; |
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ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, |
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NULL, 0, gfp_mask, sg_kmalloc); |
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if (unlikely(ret)) |
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__sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); |
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return ret; } EXPORT_SYMBOL(sg_alloc_table); |
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static struct scatterlist *get_next_sg(struct sg_table *table, struct scatterlist *cur, unsigned long needed_sges, gfp_t gfp_mask) { struct scatterlist *new_sg, *next_sg; unsigned int alloc_size; if (cur) { next_sg = sg_next(cur); /* Check if last entry should be keeped for chainning */ if (!sg_is_last(next_sg) || needed_sges == 1) return next_sg; } alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); new_sg = sg_kmalloc(alloc_size, gfp_mask); if (!new_sg) return ERR_PTR(-ENOMEM); sg_init_table(new_sg, alloc_size); if (cur) { __sg_chain(next_sg, new_sg); table->orig_nents += alloc_size - 1; } else { table->sgl = new_sg; table->orig_nents = alloc_size; table->nents = 0; } return new_sg; } |
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/** |
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* __sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages * @sgt: The sg table header to use * @pages: Pointer to an array of page pointers * @n_pages: Number of pages in the pages array * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) |
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* @max_segment: Maximum size of a scatterlist element in bytes |
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* @prv: Last populated sge in sgt * @left_pages: Left pages caller have to set after this call |
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* @gfp_mask: GFP allocation mask |
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* |
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* Description: * If @prv is NULL, allocate and initialize an sg table from a list of pages, * else reuse the scatterlist passed in at @prv. * Contiguous ranges of the pages are squashed into a single scatterlist * entry up to the maximum size specified in @max_segment. A user may * provide an offset at a start and a size of valid data in a buffer * specified by the page array. |
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* * Returns: |
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* Last SGE in sgt on success, PTR_ERR on otherwise. * The allocation in @sgt must be released by sg_free_table. * * Notes: * If this function returns non-0 (eg failure), the caller must call * sg_free_table() to cleanup any leftover allocations. |
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*/ |
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struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, unsigned int max_segment, struct scatterlist *prv, unsigned int left_pages, gfp_t gfp_mask) |
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{ |
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unsigned int chunks, cur_page, seg_len, i, prv_len = 0; unsigned int added_nents = 0; struct scatterlist *s = prv; |
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|
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/* * The algorithm below requires max_segment to be aligned to PAGE_SIZE * otherwise it can overshoot. */ max_segment = ALIGN_DOWN(max_segment, PAGE_SIZE); if (WARN_ON(max_segment < PAGE_SIZE)) |
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return ERR_PTR(-EINVAL); if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv) return ERR_PTR(-EOPNOTSUPP); if (prv) { unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE + prv->offset + prv->length) / PAGE_SIZE; if (WARN_ON(offset)) return ERR_PTR(-EINVAL); /* Merge contiguous pages into the last SG */ prv_len = prv->length; while (n_pages && page_to_pfn(pages[0]) == paddr) { if (prv->length + PAGE_SIZE > max_segment) break; prv->length += PAGE_SIZE; paddr++; pages++; n_pages--; } if (!n_pages) goto out; } |
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|
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/* compute number of contiguous chunks */ chunks = 1; |
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seg_len = 0; for (i = 1; i < n_pages; i++) { seg_len += PAGE_SIZE; if (seg_len >= max_segment || page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { chunks++; seg_len = 0; } } |
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|
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/* merging chunks and putting them into the scatterlist */ cur_page = 0; |
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for (i = 0; i < chunks; i++) { |
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unsigned int j, chunk_size; |
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/* look for the end of the current chunk */ |
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seg_len = 0; for (j = cur_page + 1; j < n_pages; j++) { seg_len += PAGE_SIZE; if (seg_len >= max_segment || page_to_pfn(pages[j]) != |
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page_to_pfn(pages[j - 1]) + 1) break; |
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} |
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|
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/* Pass how many chunks might be left */ s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask); if (IS_ERR(s)) { /* * Adjust entry length to be as before function was * called. */ if (prv) prv->length = prv_len; return s; } |
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chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; |
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sg_set_page(s, pages[cur_page], min_t(unsigned long, size, chunk_size), offset); |
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added_nents++; |
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size -= chunk_size; offset = 0; cur_page = j; } |
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sgt->nents += added_nents; out: if (!left_pages) sg_mark_end(s); return s; |
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} |
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EXPORT_SYMBOL(__sg_alloc_table_from_pages); /** * sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages * @sgt: The sg table header to use * @pages: Pointer to an array of page pointers * @n_pages: Number of pages in the pages array * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) * @gfp_mask: GFP allocation mask * * Description: * Allocate and initialize an sg table from a list of pages. Contiguous * ranges of the pages are squashed into a single scatterlist node. A user * may provide an offset at a start and a size of valid data in a buffer * specified by the page array. The returned sg table is released by * sg_free_table. * * Returns: * 0 on success, negative error on failure */ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask) { |
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return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages, |
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offset, size, UINT_MAX, NULL, 0, gfp_mask)); |
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} |
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EXPORT_SYMBOL(sg_alloc_table_from_pages); |
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#ifdef CONFIG_SGL_ALLOC /** * sgl_alloc_order - allocate a scatterlist and its pages * @length: Length in bytes of the scatterlist. Must be at least one * @order: Second argument for alloc_pages() * @chainable: Whether or not to allocate an extra element in the scatterlist * for scatterlist chaining purposes * @gfp: Memory allocation flags * @nent_p: [out] Number of entries in the scatterlist that have pages * * Returns: A pointer to an initialized scatterlist or %NULL upon failure. */ struct scatterlist *sgl_alloc_order(unsigned long long length, unsigned int order, bool chainable, gfp_t gfp, unsigned int *nent_p) { struct scatterlist *sgl, *sg; struct page *page; unsigned int nent, nalloc; u32 elem_len; nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); /* Check for integer overflow */ if (length > (nent << (PAGE_SHIFT + order))) return NULL; nalloc = nent; if (chainable) { /* Check for integer overflow */ if (nalloc + 1 < nalloc) return NULL; nalloc++; } sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), |
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gfp & ~GFP_DMA); |
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if (!sgl) return NULL; |
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sg_init_table(sgl, nalloc); |
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sg = sgl; while (length) { elem_len = min_t(u64, length, PAGE_SIZE << order); page = alloc_pages(gfp, order); if (!page) { |
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sgl_free_order(sgl, order); |
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return NULL; } sg_set_page(sg, page, elem_len, 0); length -= elem_len; sg = sg_next(sg); } |
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WARN_ONCE(length, "length = %lld ", length); |
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597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 |
if (nent_p) *nent_p = nent; return sgl; } EXPORT_SYMBOL(sgl_alloc_order); /** * sgl_alloc - allocate a scatterlist and its pages * @length: Length in bytes of the scatterlist * @gfp: Memory allocation flags * @nent_p: [out] Number of entries in the scatterlist * * Returns: A pointer to an initialized scatterlist or %NULL upon failure. */ struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, unsigned int *nent_p) { return sgl_alloc_order(length, 0, false, gfp, nent_p); } EXPORT_SYMBOL(sgl_alloc); /** |
8c7a8d1c4 lib/scatterlist: ... |
619 |
* sgl_free_n_order - free a scatterlist and its pages |
e80a0af47 lib/scatterlist: ... |
620 |
* @sgl: Scatterlist with one or more elements |
8c7a8d1c4 lib/scatterlist: ... |
621 |
* @nents: Maximum number of elements to free |
e80a0af47 lib/scatterlist: ... |
622 |
* @order: Second argument for __free_pages() |
8c7a8d1c4 lib/scatterlist: ... |
623 624 625 626 627 628 629 |
* * Notes: * - If several scatterlists have been chained and each chain element is * freed separately then it's essential to set nents correctly to avoid that a * page would get freed twice. * - All pages in a chained scatterlist can be freed at once by setting @nents * to a high number. |
e80a0af47 lib/scatterlist: ... |
630 |
*/ |
8c7a8d1c4 lib/scatterlist: ... |
631 |
void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) |
e80a0af47 lib/scatterlist: ... |
632 633 634 |
{ struct scatterlist *sg; struct page *page; |
8c7a8d1c4 lib/scatterlist: ... |
635 |
int i; |
e80a0af47 lib/scatterlist: ... |
636 |
|
8c7a8d1c4 lib/scatterlist: ... |
637 638 639 |
for_each_sg(sgl, sg, nents, i) { if (!sg) break; |
e80a0af47 lib/scatterlist: ... |
640 641 642 643 644 645 |
page = sg_page(sg); if (page) __free_pages(page, order); } kfree(sgl); } |
8c7a8d1c4 lib/scatterlist: ... |
646 647 648 649 650 651 652 653 654 655 656 |
EXPORT_SYMBOL(sgl_free_n_order); /** * sgl_free_order - free a scatterlist and its pages * @sgl: Scatterlist with one or more elements * @order: Second argument for __free_pages() */ void sgl_free_order(struct scatterlist *sgl, int order) { sgl_free_n_order(sgl, INT_MAX, order); } |
e80a0af47 lib/scatterlist: ... |
657 658 659 660 661 662 663 664 665 666 667 668 669 |
EXPORT_SYMBOL(sgl_free_order); /** * sgl_free - free a scatterlist and its pages * @sgl: Scatterlist with one or more elements */ void sgl_free(struct scatterlist *sgl) { sgl_free_order(sgl, 0); } EXPORT_SYMBOL(sgl_free); #endif /* CONFIG_SGL_ALLOC */ |
a321e91b6 lib/scatterlist: ... |
670 671 672 673 674 675 |
void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset) { piter->__pg_advance = 0; piter->__nents = nents; |
a321e91b6 lib/scatterlist: ... |
676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 |
piter->sg = sglist; piter->sg_pgoffset = pgoffset; } EXPORT_SYMBOL(__sg_page_iter_start); static int sg_page_count(struct scatterlist *sg) { return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; } bool __sg_page_iter_next(struct sg_page_iter *piter) { if (!piter->__nents || !piter->sg) return false; piter->sg_pgoffset += piter->__pg_advance; piter->__pg_advance = 1; while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { piter->sg_pgoffset -= sg_page_count(piter->sg); piter->sg = sg_next(piter->sg); if (!--piter->__nents || !piter->sg) return false; } |
a321e91b6 lib/scatterlist: ... |
700 701 702 703 |
return true; } EXPORT_SYMBOL(__sg_page_iter_next); |
d901b2760 lib/scatterlist: ... |
704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 |
static int sg_dma_page_count(struct scatterlist *sg) { return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; } bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) { struct sg_page_iter *piter = &dma_iter->base; if (!piter->__nents || !piter->sg) return false; piter->sg_pgoffset += piter->__pg_advance; piter->__pg_advance = 1; while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { piter->sg_pgoffset -= sg_dma_page_count(piter->sg); piter->sg = sg_next(piter->sg); if (!--piter->__nents || !piter->sg) return false; } return true; } EXPORT_SYMBOL(__sg_page_iter_dma_next); |
efc42bc98 scatterlist: add ... |
729 |
/** |
137d3edb4 sg: reimplement s... |
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 |
* sg_miter_start - start mapping iteration over a sg list * @miter: sg mapping iter to be started * @sgl: sg list to iterate over * @nents: number of sg entries * * Description: * Starts mapping iterator @miter. * * Context: * Don't care. */ void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, unsigned int nents, unsigned int flags) { memset(miter, 0, sizeof(struct sg_mapping_iter)); |
4225fc855 lib/scatterlist: ... |
745 |
__sg_page_iter_start(&miter->piter, sgl, nents, 0); |
6de7e356f lib/scatterlist: ... |
746 |
WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); |
137d3edb4 sg: reimplement s... |
747 748 749 |
miter->__flags = flags; } EXPORT_SYMBOL(sg_miter_start); |
110520048 lib/scatterlist: ... |
750 751 752 753 |
static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) { if (!miter->__remaining) { struct scatterlist *sg; |
110520048 lib/scatterlist: ... |
754 755 756 757 758 |
if (!__sg_page_iter_next(&miter->piter)) return false; sg = miter->piter.sg; |
110520048 lib/scatterlist: ... |
759 |
|
aeb872465 lib/scatterlist: ... |
760 761 762 |
miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset; miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT; miter->__offset &= PAGE_SIZE - 1; |
110520048 lib/scatterlist: ... |
763 |
miter->__remaining = sg->offset + sg->length - |
aeb872465 lib/scatterlist: ... |
764 765 |
(miter->piter.sg_pgoffset << PAGE_SHIFT) - miter->__offset; |
110520048 lib/scatterlist: ... |
766 767 768 769 770 771 |
miter->__remaining = min_t(unsigned long, miter->__remaining, PAGE_SIZE - miter->__offset); } return true; } |
137d3edb4 sg: reimplement s... |
772 |
/** |
df642cea2 lib/scatterlist: ... |
773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 |
* sg_miter_skip - reposition mapping iterator * @miter: sg mapping iter to be skipped * @offset: number of bytes to plus the current location * * Description: * Sets the offset of @miter to its current location plus @offset bytes. * If mapping iterator @miter has been proceeded by sg_miter_next(), this * stops @miter. * * Context: * Don't care if @miter is stopped, or not proceeded yet. * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set. * * Returns: * true if @miter contains the valid mapping. false if end of sg * list is reached. */ |
0d6077f8b lib/scatterlist: ... |
790 |
bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) |
df642cea2 lib/scatterlist: ... |
791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 |
{ sg_miter_stop(miter); while (offset) { off_t consumed; if (!sg_miter_get_next_page(miter)) return false; consumed = min_t(off_t, offset, miter->__remaining); miter->__offset += consumed; miter->__remaining -= consumed; offset -= consumed; } return true; } |
0d6077f8b lib/scatterlist: ... |
808 |
EXPORT_SYMBOL(sg_miter_skip); |
df642cea2 lib/scatterlist: ... |
809 810 |
/** |
137d3edb4 sg: reimplement s... |
811 812 813 814 |
* sg_miter_next - proceed mapping iterator to the next mapping * @miter: sg mapping iter to proceed * * Description: |
8290e2d2d scatterlist: atom... |
815 816 817 |
* Proceeds @miter to the next mapping. @miter should have been started * using sg_miter_start(). On successful return, @miter->page, * @miter->addr and @miter->length point to the current mapping. |
137d3edb4 sg: reimplement s... |
818 819 |
* * Context: |
8290e2d2d scatterlist: atom... |
820 821 |
* Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled * till @miter is stopped. May sleep if !SG_MITER_ATOMIC. |
137d3edb4 sg: reimplement s... |
822 823 824 825 826 827 828 |
* * Returns: * true if @miter contains the next mapping. false if end of sg * list is reached. */ bool sg_miter_next(struct sg_mapping_iter *miter) { |
137d3edb4 sg: reimplement s... |
829 |
sg_miter_stop(miter); |
4225fc855 lib/scatterlist: ... |
830 831 832 833 |
/* * Get to the next page if necessary. * __remaining, __offset is adjusted by sg_miter_stop */ |
110520048 lib/scatterlist: ... |
834 835 |
if (!sg_miter_get_next_page(miter)) return false; |
137d3edb4 sg: reimplement s... |
836 |
|
2db76d7c3 lib/scatterlist: ... |
837 |
miter->page = sg_page_iter_page(&miter->piter); |
4225fc855 lib/scatterlist: ... |
838 |
miter->consumed = miter->length = miter->__remaining; |
137d3edb4 sg: reimplement s... |
839 840 |
if (miter->__flags & SG_MITER_ATOMIC) |
4225fc855 lib/scatterlist: ... |
841 |
miter->addr = kmap_atomic(miter->page) + miter->__offset; |
137d3edb4 sg: reimplement s... |
842 |
else |
4225fc855 lib/scatterlist: ... |
843 |
miter->addr = kmap(miter->page) + miter->__offset; |
137d3edb4 sg: reimplement s... |
844 845 846 847 848 849 850 851 852 853 854 |
return true; } EXPORT_SYMBOL(sg_miter_next); /** * sg_miter_stop - stop mapping iteration * @miter: sg mapping iter to be stopped * * Description: * Stops mapping iterator @miter. @miter should have been started |
4ba6a2b28 scatterlist: fix ... |
855 856 857 |
* using sg_miter_start(). A stopped iteration can be resumed by * calling sg_miter_next() on it. This is useful when resources (kmap) * need to be released during iteration. |
137d3edb4 sg: reimplement s... |
858 859 |
* * Context: |
8290e2d2d scatterlist: atom... |
860 861 |
* Preemption disabled if the SG_MITER_ATOMIC is set. Don't care * otherwise. |
137d3edb4 sg: reimplement s... |
862 863 864 865 866 867 868 869 |
*/ void sg_miter_stop(struct sg_mapping_iter *miter) { WARN_ON(miter->consumed > miter->length); /* drop resources from the last iteration */ if (miter->addr) { miter->__offset += miter->consumed; |
4225fc855 lib/scatterlist: ... |
870 |
miter->__remaining -= miter->consumed; |
137d3edb4 sg: reimplement s... |
871 |
|
3d77b50c5 lib/scatterlist.c... |
872 873 |
if ((miter->__flags & SG_MITER_TO_SG) && !PageSlab(miter->page)) |
6de7e356f lib/scatterlist: ... |
874 |
flush_kernel_dcache_page(miter->page); |
137d3edb4 sg: reimplement s... |
875 |
if (miter->__flags & SG_MITER_ATOMIC) { |
8290e2d2d scatterlist: atom... |
876 |
WARN_ON_ONCE(preemptible()); |
c3eede8e0 lib: remove the s... |
877 |
kunmap_atomic(miter->addr); |
137d3edb4 sg: reimplement s... |
878 |
} else |
f652c521e lib/scatterlist.c... |
879 |
kunmap(miter->page); |
137d3edb4 sg: reimplement s... |
880 881 882 883 884 885 886 887 888 889 |
miter->page = NULL; miter->addr = NULL; miter->length = 0; miter->consumed = 0; } } EXPORT_SYMBOL(sg_miter_stop); /** |
b1adaf65b [SCSI] block: add... |
890 891 892 893 894 |
* sg_copy_buffer - Copy data between a linear buffer and an SG list * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy from * @buflen: The number of bytes to copy |
df642cea2 lib/scatterlist: ... |
895 896 |
* @skip: Number of bytes to skip before copying * @to_buffer: transfer direction (true == from an sg list to a |
6e8531852 lib/scatterlist: ... |
897 |
* buffer, false == from a buffer to an sg list) |
b1adaf65b [SCSI] block: add... |
898 899 900 901 |
* * Returns the number of copied bytes. * **/ |
386ecb121 drivers/scsi/scsi... |
902 903 |
size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, off_t skip, bool to_buffer) |
b1adaf65b [SCSI] block: add... |
904 |
{ |
137d3edb4 sg: reimplement s... |
905 906 |
unsigned int offset = 0; struct sg_mapping_iter miter; |
6de7e356f lib/scatterlist: ... |
907 908 909 910 911 912 |
unsigned int sg_flags = SG_MITER_ATOMIC; if (to_buffer) sg_flags |= SG_MITER_FROM_SG; else sg_flags |= SG_MITER_TO_SG; |
137d3edb4 sg: reimplement s... |
913 |
|
6de7e356f lib/scatterlist: ... |
914 |
sg_miter_start(&miter, sgl, nents, sg_flags); |
137d3edb4 sg: reimplement s... |
915 |
|
df642cea2 lib/scatterlist: ... |
916 |
if (!sg_miter_skip(&miter, skip)) |
1f41be7d4 lib/scatterlist: ... |
917 |
return 0; |
df642cea2 lib/scatterlist: ... |
918 |
|
1d5210ef7 scatterlist: reor... |
919 |
while ((offset < buflen) && sg_miter_next(&miter)) { |
137d3edb4 sg: reimplement s... |
920 921 922 923 924 925 |
unsigned int len; len = min(miter.length, buflen - offset); if (to_buffer) memcpy(buf + offset, miter.addr, len); |
6de7e356f lib/scatterlist: ... |
926 |
else |
137d3edb4 sg: reimplement s... |
927 |
memcpy(miter.addr, buf + offset, len); |
b1adaf65b [SCSI] block: add... |
928 |
|
137d3edb4 sg: reimplement s... |
929 |
offset += len; |
b1adaf65b [SCSI] block: add... |
930 |
} |
137d3edb4 sg: reimplement s... |
931 932 933 |
sg_miter_stop(&miter); return offset; |
b1adaf65b [SCSI] block: add... |
934 |
} |
386ecb121 drivers/scsi/scsi... |
935 |
EXPORT_SYMBOL(sg_copy_buffer); |
b1adaf65b [SCSI] block: add... |
936 937 938 939 940 941 942 943 944 945 946 947 |
/** * sg_copy_from_buffer - Copy from a linear buffer to an SG list * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy from * @buflen: The number of bytes to copy * * Returns the number of copied bytes. * **/ size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f93 lib/scatterlist: ... |
948 |
const void *buf, size_t buflen) |
b1adaf65b [SCSI] block: add... |
949 |
{ |
2a1bf8f93 lib/scatterlist: ... |
950 |
return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); |
b1adaf65b [SCSI] block: add... |
951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 |
} EXPORT_SYMBOL(sg_copy_from_buffer); /** * sg_copy_to_buffer - Copy from an SG list to a linear buffer * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy to * @buflen: The number of bytes to copy * * Returns the number of copied bytes. * **/ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen) { |
df642cea2 lib/scatterlist: ... |
967 |
return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); |
b1adaf65b [SCSI] block: add... |
968 969 |
} EXPORT_SYMBOL(sg_copy_to_buffer); |
df642cea2 lib/scatterlist: ... |
970 971 972 973 974 975 |
/** * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy from |
df642cea2 lib/scatterlist: ... |
976 |
* @buflen: The number of bytes to copy |
4dc7daf84 lib/scatterlist.c... |
977 |
* @skip: Number of bytes to skip before copying |
df642cea2 lib/scatterlist: ... |
978 979 980 981 982 |
* * Returns the number of copied bytes. * **/ size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f93 lib/scatterlist: ... |
983 |
const void *buf, size_t buflen, off_t skip) |
df642cea2 lib/scatterlist: ... |
984 |
{ |
2a1bf8f93 lib/scatterlist: ... |
985 |
return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); |
df642cea2 lib/scatterlist: ... |
986 987 988 989 990 991 992 993 |
} EXPORT_SYMBOL(sg_pcopy_from_buffer); /** * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy to |
df642cea2 lib/scatterlist: ... |
994 |
* @buflen: The number of bytes to copy |
4dc7daf84 lib/scatterlist.c... |
995 |
* @skip: Number of bytes to skip before copying |
df642cea2 lib/scatterlist: ... |
996 997 998 999 1000 1001 1002 1003 1004 1005 |
* * Returns the number of copied bytes. * **/ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, off_t skip) { return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); } EXPORT_SYMBOL(sg_pcopy_to_buffer); |
0945e5699 scatterlist: add ... |
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 |
/** * sg_zero_buffer - Zero-out a part of a SG list * @sgl: The SG list * @nents: Number of SG entries * @buflen: The number of bytes to zero out * @skip: Number of bytes to skip before zeroing * * Returns the number of bytes zeroed. **/ size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, size_t buflen, off_t skip) { unsigned int offset = 0; struct sg_mapping_iter miter; unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; sg_miter_start(&miter, sgl, nents, sg_flags); if (!sg_miter_skip(&miter, skip)) return false; while (offset < buflen && sg_miter_next(&miter)) { unsigned int len; len = min(miter.length, buflen - offset); memset(miter.addr, 0, len); offset += len; } sg_miter_stop(&miter); return offset; } EXPORT_SYMBOL(sg_zero_buffer); |