140b0b3f8SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 20db9299fSJens Axboe /* 30db9299fSJens Axboe * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com> 40db9299fSJens Axboe * 50db9299fSJens Axboe * Scatterlist handling helpers. 60db9299fSJens Axboe */ 78bc3bcc9SPaul Gortmaker #include <linux/export.h> 85a0e3ad6STejun Heo #include <linux/slab.h> 90db9299fSJens Axboe #include <linux/scatterlist.h> 10b1adaf65SFUJITA Tomonori #include <linux/highmem.h> 11b94de9bbSChris Wilson #include <linux/kmemleak.h> 120db9299fSJens Axboe 130db9299fSJens Axboe /** 140db9299fSJens Axboe * sg_next - return the next scatterlist entry in a list 150db9299fSJens Axboe * @sg: The current sg entry 160db9299fSJens Axboe * 170db9299fSJens Axboe * Description: 180db9299fSJens Axboe * Usually the next entry will be @sg@ + 1, but if this sg element is part 190db9299fSJens Axboe * of a chained scatterlist, it could jump to the start of a new 200db9299fSJens Axboe * scatterlist array. 210db9299fSJens Axboe * 220db9299fSJens Axboe **/ 230db9299fSJens Axboe struct scatterlist *sg_next(struct scatterlist *sg) 240db9299fSJens Axboe { 250db9299fSJens Axboe if (sg_is_last(sg)) 260db9299fSJens Axboe return NULL; 270db9299fSJens Axboe 280db9299fSJens Axboe sg++; 290db9299fSJens Axboe if (unlikely(sg_is_chain(sg))) 300db9299fSJens Axboe sg = sg_chain_ptr(sg); 310db9299fSJens Axboe 320db9299fSJens Axboe return sg; 330db9299fSJens Axboe } 340db9299fSJens Axboe EXPORT_SYMBOL(sg_next); 350db9299fSJens Axboe 360db9299fSJens Axboe /** 372e484610SMaxim Levitsky * sg_nents - return total count of entries in scatterlist 382e484610SMaxim Levitsky * @sg: The scatterlist 392e484610SMaxim Levitsky * 402e484610SMaxim Levitsky * Description: 412e484610SMaxim Levitsky * Allows to know how many entries are in sg, taking into acount 422e484610SMaxim Levitsky * chaining as well 432e484610SMaxim Levitsky * 442e484610SMaxim Levitsky **/ 452e484610SMaxim Levitsky int sg_nents(struct scatterlist *sg) 462e484610SMaxim Levitsky { 47232f1b51SMaxim Levitsky int nents; 48232f1b51SMaxim Levitsky for (nents = 0; sg; sg = sg_next(sg)) 492e484610SMaxim Levitsky nents++; 502e484610SMaxim Levitsky return nents; 512e484610SMaxim Levitsky } 522e484610SMaxim Levitsky EXPORT_SYMBOL(sg_nents); 532e484610SMaxim Levitsky 54cfaed10dSTom Lendacky /** 55cfaed10dSTom Lendacky * sg_nents_for_len - return total count of entries in scatterlist 56cfaed10dSTom Lendacky * needed to satisfy the supplied length 57cfaed10dSTom Lendacky * @sg: The scatterlist 58cfaed10dSTom Lendacky * @len: The total required length 59cfaed10dSTom Lendacky * 60cfaed10dSTom Lendacky * Description: 61cfaed10dSTom Lendacky * Determines the number of entries in sg that are required to meet 62cfaed10dSTom Lendacky * the supplied length, taking into acount chaining as well 63cfaed10dSTom Lendacky * 64cfaed10dSTom Lendacky * Returns: 65cfaed10dSTom Lendacky * the number of sg entries needed, negative error on failure 66cfaed10dSTom Lendacky * 67cfaed10dSTom Lendacky **/ 68cfaed10dSTom Lendacky int sg_nents_for_len(struct scatterlist *sg, u64 len) 69cfaed10dSTom Lendacky { 70cfaed10dSTom Lendacky int nents; 71cfaed10dSTom Lendacky u64 total; 72cfaed10dSTom Lendacky 73cfaed10dSTom Lendacky if (!len) 74cfaed10dSTom Lendacky return 0; 75cfaed10dSTom Lendacky 76cfaed10dSTom Lendacky for (nents = 0, total = 0; sg; sg = sg_next(sg)) { 77cfaed10dSTom Lendacky nents++; 78cfaed10dSTom Lendacky total += sg->length; 79cfaed10dSTom Lendacky if (total >= len) 80cfaed10dSTom Lendacky return nents; 81cfaed10dSTom Lendacky } 82cfaed10dSTom Lendacky 83cfaed10dSTom Lendacky return -EINVAL; 84cfaed10dSTom Lendacky } 85cfaed10dSTom Lendacky EXPORT_SYMBOL(sg_nents_for_len); 862e484610SMaxim Levitsky 872e484610SMaxim Levitsky /** 880db9299fSJens Axboe * sg_last - return the last scatterlist entry in a list 890db9299fSJens Axboe * @sgl: First entry in the scatterlist 900db9299fSJens Axboe * @nents: Number of entries in the scatterlist 910db9299fSJens Axboe * 920db9299fSJens Axboe * Description: 930db9299fSJens Axboe * Should only be used casually, it (currently) scans the entire list 940db9299fSJens Axboe * to get the last entry. 950db9299fSJens Axboe * 960db9299fSJens Axboe * Note that the @sgl@ pointer passed in need not be the first one, 970db9299fSJens Axboe * the important bit is that @nents@ denotes the number of entries that 980db9299fSJens Axboe * exist from @sgl@. 990db9299fSJens Axboe * 1000db9299fSJens Axboe **/ 1010db9299fSJens Axboe struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) 1020db9299fSJens Axboe { 1030db9299fSJens Axboe struct scatterlist *sg, *ret = NULL; 1040db9299fSJens Axboe unsigned int i; 1050db9299fSJens Axboe 1060db9299fSJens Axboe for_each_sg(sgl, sg, nents, i) 1070db9299fSJens Axboe ret = sg; 1080db9299fSJens Axboe 1090db9299fSJens Axboe BUG_ON(!sg_is_last(ret)); 1100db9299fSJens Axboe return ret; 1110db9299fSJens Axboe } 1120db9299fSJens Axboe EXPORT_SYMBOL(sg_last); 1130db9299fSJens Axboe 1140db9299fSJens Axboe /** 1150db9299fSJens Axboe * sg_init_table - Initialize SG table 1160db9299fSJens Axboe * @sgl: The SG table 1170db9299fSJens Axboe * @nents: Number of entries in table 1180db9299fSJens Axboe * 1190db9299fSJens Axboe * Notes: 1200db9299fSJens Axboe * If this is part of a chained sg table, sg_mark_end() should be 1210db9299fSJens Axboe * used only on the last table part. 1220db9299fSJens Axboe * 1230db9299fSJens Axboe **/ 1240db9299fSJens Axboe void sg_init_table(struct scatterlist *sgl, unsigned int nents) 1250db9299fSJens Axboe { 1260db9299fSJens Axboe memset(sgl, 0, sizeof(*sgl) * nents); 127f3851786SPrashant Bhole sg_init_marker(sgl, nents); 1280db9299fSJens Axboe } 1290db9299fSJens Axboe EXPORT_SYMBOL(sg_init_table); 1300db9299fSJens Axboe 1310db9299fSJens Axboe /** 1320db9299fSJens Axboe * sg_init_one - Initialize a single entry sg list 1330db9299fSJens Axboe * @sg: SG entry 1340db9299fSJens Axboe * @buf: Virtual address for IO 1350db9299fSJens Axboe * @buflen: IO length 1360db9299fSJens Axboe * 1370db9299fSJens Axboe **/ 1380db9299fSJens Axboe void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) 1390db9299fSJens Axboe { 1400db9299fSJens Axboe sg_init_table(sg, 1); 1410db9299fSJens Axboe sg_set_buf(sg, buf, buflen); 1420db9299fSJens Axboe } 1430db9299fSJens Axboe EXPORT_SYMBOL(sg_init_one); 1440db9299fSJens Axboe 1450db9299fSJens Axboe /* 1460db9299fSJens Axboe * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree 1470db9299fSJens Axboe * helpers. 1480db9299fSJens Axboe */ 1490db9299fSJens Axboe static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) 1500db9299fSJens Axboe { 151b94de9bbSChris Wilson if (nents == SG_MAX_SINGLE_ALLOC) { 152b94de9bbSChris Wilson /* 153b94de9bbSChris Wilson * Kmemleak doesn't track page allocations as they are not 154b94de9bbSChris Wilson * commonly used (in a raw form) for kernel data structures. 155b94de9bbSChris Wilson * As we chain together a list of pages and then a normal 156b94de9bbSChris Wilson * kmalloc (tracked by kmemleak), in order to for that last 157b94de9bbSChris Wilson * allocation not to become decoupled (and thus a 158b94de9bbSChris Wilson * false-positive) we need to inform kmemleak of all the 159b94de9bbSChris Wilson * intermediate allocations. 160b94de9bbSChris Wilson */ 161b94de9bbSChris Wilson void *ptr = (void *) __get_free_page(gfp_mask); 162b94de9bbSChris Wilson kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask); 163b94de9bbSChris Wilson return ptr; 164b94de9bbSChris Wilson } else 1656da2ec56SKees Cook return kmalloc_array(nents, sizeof(struct scatterlist), 1666da2ec56SKees Cook gfp_mask); 1670db9299fSJens Axboe } 1680db9299fSJens Axboe 1690db9299fSJens Axboe static void sg_kfree(struct scatterlist *sg, unsigned int nents) 1700db9299fSJens Axboe { 171b94de9bbSChris Wilson if (nents == SG_MAX_SINGLE_ALLOC) { 172b94de9bbSChris Wilson kmemleak_free(sg); 1730db9299fSJens Axboe free_page((unsigned long) sg); 174b94de9bbSChris Wilson } else 1750db9299fSJens Axboe kfree(sg); 1760db9299fSJens Axboe } 1770db9299fSJens Axboe 1780db9299fSJens Axboe /** 1790db9299fSJens Axboe * __sg_free_table - Free a previously mapped sg table 1800db9299fSJens Axboe * @table: The sg table header to use 1817cedb1f1SJames Bottomley * @max_ents: The maximum number of entries per single scatterlist 182c53c6d6aSChristoph Hellwig * @skip_first_chunk: don't free the (preallocated) first scatterlist chunk 1830db9299fSJens Axboe * @free_fn: Free function 1840db9299fSJens Axboe * 1850db9299fSJens Axboe * Description: 1867cedb1f1SJames Bottomley * Free an sg table previously allocated and setup with 1877cedb1f1SJames Bottomley * __sg_alloc_table(). The @max_ents value must be identical to 1887cedb1f1SJames Bottomley * that previously used with __sg_alloc_table(). 1890db9299fSJens Axboe * 1900db9299fSJens Axboe **/ 1917cedb1f1SJames Bottomley void __sg_free_table(struct sg_table *table, unsigned int max_ents, 192c53c6d6aSChristoph Hellwig bool skip_first_chunk, sg_free_fn *free_fn) 1930db9299fSJens Axboe { 1940db9299fSJens Axboe struct scatterlist *sgl, *next; 1950db9299fSJens Axboe 1960db9299fSJens Axboe if (unlikely(!table->sgl)) 1970db9299fSJens Axboe return; 1980db9299fSJens Axboe 1990db9299fSJens Axboe sgl = table->sgl; 2000db9299fSJens Axboe while (table->orig_nents) { 2010db9299fSJens Axboe unsigned int alloc_size = table->orig_nents; 2020db9299fSJens Axboe unsigned int sg_size; 2030db9299fSJens Axboe 2040db9299fSJens Axboe /* 2057cedb1f1SJames Bottomley * If we have more than max_ents segments left, 2060db9299fSJens Axboe * then assign 'next' to the sg table after the current one. 2070db9299fSJens Axboe * sg_size is then one less than alloc size, since the last 2080db9299fSJens Axboe * element is the chain pointer. 2090db9299fSJens Axboe */ 2107cedb1f1SJames Bottomley if (alloc_size > max_ents) { 2117cedb1f1SJames Bottomley next = sg_chain_ptr(&sgl[max_ents - 1]); 2127cedb1f1SJames Bottomley alloc_size = max_ents; 2130db9299fSJens Axboe sg_size = alloc_size - 1; 2140db9299fSJens Axboe } else { 2150db9299fSJens Axboe sg_size = alloc_size; 2160db9299fSJens Axboe next = NULL; 2170db9299fSJens Axboe } 2180db9299fSJens Axboe 2190db9299fSJens Axboe table->orig_nents -= sg_size; 220c21e59d8STony Battersby if (skip_first_chunk) 221c53c6d6aSChristoph Hellwig skip_first_chunk = false; 222c21e59d8STony Battersby else 223c21e59d8STony Battersby free_fn(sgl, alloc_size); 2240db9299fSJens Axboe sgl = next; 2250db9299fSJens Axboe } 2260db9299fSJens Axboe 2270db9299fSJens Axboe table->sgl = NULL; 2280db9299fSJens Axboe } 2290db9299fSJens Axboe EXPORT_SYMBOL(__sg_free_table); 2300db9299fSJens Axboe 2310db9299fSJens Axboe /** 2320db9299fSJens Axboe * sg_free_table - Free a previously allocated sg table 2330db9299fSJens Axboe * @table: The mapped sg table header 2340db9299fSJens Axboe * 2350db9299fSJens Axboe **/ 2360db9299fSJens Axboe void sg_free_table(struct sg_table *table) 2370db9299fSJens Axboe { 238c53c6d6aSChristoph Hellwig __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree); 2390db9299fSJens Axboe } 2400db9299fSJens Axboe EXPORT_SYMBOL(sg_free_table); 2410db9299fSJens Axboe 2420db9299fSJens Axboe /** 2430db9299fSJens Axboe * __sg_alloc_table - Allocate and initialize an sg table with given allocator 2440db9299fSJens Axboe * @table: The sg table header to use 2450db9299fSJens Axboe * @nents: Number of entries in sg list 2467cedb1f1SJames Bottomley * @max_ents: The maximum number of entries the allocator returns per call 2470db9299fSJens Axboe * @gfp_mask: GFP allocation mask 2480db9299fSJens Axboe * @alloc_fn: Allocator to use 2490db9299fSJens Axboe * 2507cedb1f1SJames Bottomley * Description: 2517cedb1f1SJames Bottomley * This function returns a @table @nents long. The allocator is 2527cedb1f1SJames Bottomley * defined to return scatterlist chunks of maximum size @max_ents. 2537cedb1f1SJames Bottomley * Thus if @nents is bigger than @max_ents, the scatterlists will be 2547cedb1f1SJames Bottomley * chained in units of @max_ents. 2557cedb1f1SJames Bottomley * 2560db9299fSJens Axboe * Notes: 2570db9299fSJens Axboe * If this function returns non-0 (eg failure), the caller must call 2580db9299fSJens Axboe * __sg_free_table() to cleanup any leftover allocations. 2590db9299fSJens Axboe * 2600db9299fSJens Axboe **/ 2617cedb1f1SJames Bottomley int __sg_alloc_table(struct sg_table *table, unsigned int nents, 262c53c6d6aSChristoph Hellwig unsigned int max_ents, struct scatterlist *first_chunk, 263c53c6d6aSChristoph Hellwig gfp_t gfp_mask, sg_alloc_fn *alloc_fn) 2640db9299fSJens Axboe { 2650db9299fSJens Axboe struct scatterlist *sg, *prv; 2660db9299fSJens Axboe unsigned int left; 2670db9299fSJens Axboe 26827daabd9SDan Carpenter memset(table, 0, sizeof(*table)); 26927daabd9SDan Carpenter 27027daabd9SDan Carpenter if (nents == 0) 27127daabd9SDan Carpenter return -EINVAL; 2727c703e54SChristoph Hellwig #ifdef CONFIG_ARCH_NO_SG_CHAIN 2736fd59a83SNick Bowler if (WARN_ON_ONCE(nents > max_ents)) 2746fd59a83SNick Bowler return -EINVAL; 2750db9299fSJens Axboe #endif 2760db9299fSJens Axboe 2770db9299fSJens Axboe left = nents; 2780db9299fSJens Axboe prv = NULL; 2790db9299fSJens Axboe do { 2800db9299fSJens Axboe unsigned int sg_size, alloc_size = left; 2810db9299fSJens Axboe 2827cedb1f1SJames Bottomley if (alloc_size > max_ents) { 2837cedb1f1SJames Bottomley alloc_size = max_ents; 2840db9299fSJens Axboe sg_size = alloc_size - 1; 2850db9299fSJens Axboe } else 2860db9299fSJens Axboe sg_size = alloc_size; 2870db9299fSJens Axboe 2880db9299fSJens Axboe left -= sg_size; 2890db9299fSJens Axboe 290c53c6d6aSChristoph Hellwig if (first_chunk) { 291c53c6d6aSChristoph Hellwig sg = first_chunk; 292c53c6d6aSChristoph Hellwig first_chunk = NULL; 293c53c6d6aSChristoph Hellwig } else { 2940db9299fSJens Axboe sg = alloc_fn(alloc_size, gfp_mask); 295c53c6d6aSChristoph Hellwig } 296edce6820SJeffrey Carlyle if (unlikely(!sg)) { 297edce6820SJeffrey Carlyle /* 298edce6820SJeffrey Carlyle * Adjust entry count to reflect that the last 299edce6820SJeffrey Carlyle * entry of the previous table won't be used for 300edce6820SJeffrey Carlyle * linkage. Without this, sg_kfree() may get 301edce6820SJeffrey Carlyle * confused. 302edce6820SJeffrey Carlyle */ 303edce6820SJeffrey Carlyle if (prv) 304edce6820SJeffrey Carlyle table->nents = ++table->orig_nents; 305edce6820SJeffrey Carlyle 3060db9299fSJens Axboe return -ENOMEM; 307edce6820SJeffrey Carlyle } 3080db9299fSJens Axboe 3090db9299fSJens Axboe sg_init_table(sg, alloc_size); 3100db9299fSJens Axboe table->nents = table->orig_nents += sg_size; 3110db9299fSJens Axboe 3120db9299fSJens Axboe /* 3130db9299fSJens Axboe * If this is the first mapping, assign the sg table header. 3140db9299fSJens Axboe * If this is not the first mapping, chain previous part. 3150db9299fSJens Axboe */ 3160db9299fSJens Axboe if (prv) 3177cedb1f1SJames Bottomley sg_chain(prv, max_ents, sg); 3180db9299fSJens Axboe else 3190db9299fSJens Axboe table->sgl = sg; 3200db9299fSJens Axboe 3210db9299fSJens Axboe /* 3220db9299fSJens Axboe * If no more entries after this one, mark the end 3230db9299fSJens Axboe */ 3240db9299fSJens Axboe if (!left) 3250db9299fSJens Axboe sg_mark_end(&sg[sg_size - 1]); 3260db9299fSJens Axboe 3270db9299fSJens Axboe prv = sg; 3280db9299fSJens Axboe } while (left); 3290db9299fSJens Axboe 3300db9299fSJens Axboe return 0; 3310db9299fSJens Axboe } 3320db9299fSJens Axboe EXPORT_SYMBOL(__sg_alloc_table); 3330db9299fSJens Axboe 3340db9299fSJens Axboe /** 3350db9299fSJens Axboe * sg_alloc_table - Allocate and initialize an sg table 3360db9299fSJens Axboe * @table: The sg table header to use 3370db9299fSJens Axboe * @nents: Number of entries in sg list 3380db9299fSJens Axboe * @gfp_mask: GFP allocation mask 3390db9299fSJens Axboe * 3400db9299fSJens Axboe * Description: 3410db9299fSJens Axboe * Allocate and initialize an sg table. If @nents@ is larger than 3420db9299fSJens Axboe * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. 3430db9299fSJens Axboe * 3440db9299fSJens Axboe **/ 3450db9299fSJens Axboe int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) 3460db9299fSJens Axboe { 3470db9299fSJens Axboe int ret; 3480db9299fSJens Axboe 3497cedb1f1SJames Bottomley ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, 350c53c6d6aSChristoph Hellwig NULL, gfp_mask, sg_kmalloc); 3510db9299fSJens Axboe if (unlikely(ret)) 352c53c6d6aSChristoph Hellwig __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree); 3530db9299fSJens Axboe 3540db9299fSJens Axboe return ret; 3550db9299fSJens Axboe } 3560db9299fSJens Axboe EXPORT_SYMBOL(sg_alloc_table); 357b1adaf65SFUJITA Tomonori 358b1adaf65SFUJITA Tomonori /** 35989d8589cSTvrtko Ursulin * __sg_alloc_table_from_pages - Allocate and initialize an sg table from 360efc42bc9STomasz Stanislawski * an array of pages 361efc42bc9STomasz Stanislawski * @sgt: The sg table header to use 362efc42bc9STomasz Stanislawski * @pages: Pointer to an array of page pointers 363efc42bc9STomasz Stanislawski * @n_pages: Number of pages in the pages array 364efc42bc9STomasz Stanislawski * @offset: Offset from start of the first page to the start of a buffer 365efc42bc9STomasz Stanislawski * @size: Number of valid bytes in the buffer (after offset) 36689d8589cSTvrtko Ursulin * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) 367efc42bc9STomasz Stanislawski * @gfp_mask: GFP allocation mask 368efc42bc9STomasz Stanislawski * 369efc42bc9STomasz Stanislawski * Description: 370efc42bc9STomasz Stanislawski * Allocate and initialize an sg table from a list of pages. Contiguous 37189d8589cSTvrtko Ursulin * ranges of the pages are squashed into a single scatterlist node up to the 37289d8589cSTvrtko Ursulin * maximum size specified in @max_segment. An user may provide an offset at a 37389d8589cSTvrtko Ursulin * start and a size of valid data in a buffer specified by the page array. 37489d8589cSTvrtko Ursulin * The returned sg table is released by sg_free_table. 375efc42bc9STomasz Stanislawski * 376efc42bc9STomasz Stanislawski * Returns: 377efc42bc9STomasz Stanislawski * 0 on success, negative error on failure 378efc42bc9STomasz Stanislawski */ 37989d8589cSTvrtko Ursulin int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, 38089d8589cSTvrtko Ursulin unsigned int n_pages, unsigned int offset, 38189d8589cSTvrtko Ursulin unsigned long size, unsigned int max_segment, 382efc42bc9STomasz Stanislawski gfp_t gfp_mask) 383efc42bc9STomasz Stanislawski { 384c125906bSTvrtko Ursulin unsigned int chunks, cur_page, seg_len, i; 385efc42bc9STomasz Stanislawski int ret; 386efc42bc9STomasz Stanislawski struct scatterlist *s; 387efc42bc9STomasz Stanislawski 38889d8589cSTvrtko Ursulin if (WARN_ON(!max_segment || offset_in_page(max_segment))) 38989d8589cSTvrtko Ursulin return -EINVAL; 39089d8589cSTvrtko Ursulin 391efc42bc9STomasz Stanislawski /* compute number of contiguous chunks */ 392efc42bc9STomasz Stanislawski chunks = 1; 393c125906bSTvrtko Ursulin seg_len = 0; 394c125906bSTvrtko Ursulin for (i = 1; i < n_pages; i++) { 395c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 396c125906bSTvrtko Ursulin if (seg_len >= max_segment || 397c125906bSTvrtko Ursulin page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { 398c125906bSTvrtko Ursulin chunks++; 399c125906bSTvrtko Ursulin seg_len = 0; 400c125906bSTvrtko Ursulin } 401c125906bSTvrtko Ursulin } 402efc42bc9STomasz Stanislawski 403efc42bc9STomasz Stanislawski ret = sg_alloc_table(sgt, chunks, gfp_mask); 404efc42bc9STomasz Stanislawski if (unlikely(ret)) 405efc42bc9STomasz Stanislawski return ret; 406efc42bc9STomasz Stanislawski 407efc42bc9STomasz Stanislawski /* merging chunks and putting them into the scatterlist */ 408efc42bc9STomasz Stanislawski cur_page = 0; 409efc42bc9STomasz Stanislawski for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { 410c125906bSTvrtko Ursulin unsigned int j, chunk_size; 411efc42bc9STomasz Stanislawski 412efc42bc9STomasz Stanislawski /* look for the end of the current chunk */ 413c125906bSTvrtko Ursulin seg_len = 0; 414c125906bSTvrtko Ursulin for (j = cur_page + 1; j < n_pages; j++) { 415c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 416c125906bSTvrtko Ursulin if (seg_len >= max_segment || 417c125906bSTvrtko Ursulin page_to_pfn(pages[j]) != 418efc42bc9STomasz Stanislawski page_to_pfn(pages[j - 1]) + 1) 419efc42bc9STomasz Stanislawski break; 420c125906bSTvrtko Ursulin } 421efc42bc9STomasz Stanislawski 422efc42bc9STomasz Stanislawski chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; 423c125906bSTvrtko Ursulin sg_set_page(s, pages[cur_page], 424c125906bSTvrtko Ursulin min_t(unsigned long, size, chunk_size), offset); 425efc42bc9STomasz Stanislawski size -= chunk_size; 426efc42bc9STomasz Stanislawski offset = 0; 427efc42bc9STomasz Stanislawski cur_page = j; 428efc42bc9STomasz Stanislawski } 429efc42bc9STomasz Stanislawski 430efc42bc9STomasz Stanislawski return 0; 431efc42bc9STomasz Stanislawski } 43289d8589cSTvrtko Ursulin EXPORT_SYMBOL(__sg_alloc_table_from_pages); 43389d8589cSTvrtko Ursulin 43489d8589cSTvrtko Ursulin /** 43589d8589cSTvrtko Ursulin * sg_alloc_table_from_pages - Allocate and initialize an sg table from 43689d8589cSTvrtko Ursulin * an array of pages 43789d8589cSTvrtko Ursulin * @sgt: The sg table header to use 43889d8589cSTvrtko Ursulin * @pages: Pointer to an array of page pointers 43989d8589cSTvrtko Ursulin * @n_pages: Number of pages in the pages array 44089d8589cSTvrtko Ursulin * @offset: Offset from start of the first page to the start of a buffer 44189d8589cSTvrtko Ursulin * @size: Number of valid bytes in the buffer (after offset) 44289d8589cSTvrtko Ursulin * @gfp_mask: GFP allocation mask 44389d8589cSTvrtko Ursulin * 44489d8589cSTvrtko Ursulin * Description: 44589d8589cSTvrtko Ursulin * Allocate and initialize an sg table from a list of pages. Contiguous 44689d8589cSTvrtko Ursulin * ranges of the pages are squashed into a single scatterlist node. A user 44789d8589cSTvrtko Ursulin * may provide an offset at a start and a size of valid data in a buffer 44889d8589cSTvrtko Ursulin * specified by the page array. The returned sg table is released by 44989d8589cSTvrtko Ursulin * sg_free_table. 45089d8589cSTvrtko Ursulin * 45189d8589cSTvrtko Ursulin * Returns: 45289d8589cSTvrtko Ursulin * 0 on success, negative error on failure 45389d8589cSTvrtko Ursulin */ 45489d8589cSTvrtko Ursulin int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, 45589d8589cSTvrtko Ursulin unsigned int n_pages, unsigned int offset, 45689d8589cSTvrtko Ursulin unsigned long size, gfp_t gfp_mask) 45789d8589cSTvrtko Ursulin { 45889d8589cSTvrtko Ursulin return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, 45989d8589cSTvrtko Ursulin SCATTERLIST_MAX_SEGMENT, gfp_mask); 46089d8589cSTvrtko Ursulin } 461efc42bc9STomasz Stanislawski EXPORT_SYMBOL(sg_alloc_table_from_pages); 462efc42bc9STomasz Stanislawski 463e80a0af4SBart Van Assche #ifdef CONFIG_SGL_ALLOC 464e80a0af4SBart Van Assche 465e80a0af4SBart Van Assche /** 466e80a0af4SBart Van Assche * sgl_alloc_order - allocate a scatterlist and its pages 467e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist. Must be at least one 468e80a0af4SBart Van Assche * @order: Second argument for alloc_pages() 469e80a0af4SBart Van Assche * @chainable: Whether or not to allocate an extra element in the scatterlist 470e80a0af4SBart Van Assche * for scatterlist chaining purposes 471e80a0af4SBart Van Assche * @gfp: Memory allocation flags 472e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist that have pages 473e80a0af4SBart Van Assche * 474e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 475e80a0af4SBart Van Assche */ 476e80a0af4SBart Van Assche struct scatterlist *sgl_alloc_order(unsigned long long length, 477e80a0af4SBart Van Assche unsigned int order, bool chainable, 478e80a0af4SBart Van Assche gfp_t gfp, unsigned int *nent_p) 479e80a0af4SBart Van Assche { 480e80a0af4SBart Van Assche struct scatterlist *sgl, *sg; 481e80a0af4SBart Van Assche struct page *page; 482e80a0af4SBart Van Assche unsigned int nent, nalloc; 483e80a0af4SBart Van Assche u32 elem_len; 484e80a0af4SBart Van Assche 485e80a0af4SBart Van Assche nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); 486e80a0af4SBart Van Assche /* Check for integer overflow */ 487e80a0af4SBart Van Assche if (length > (nent << (PAGE_SHIFT + order))) 488e80a0af4SBart Van Assche return NULL; 489e80a0af4SBart Van Assche nalloc = nent; 490e80a0af4SBart Van Assche if (chainable) { 491e80a0af4SBart Van Assche /* Check for integer overflow */ 492e80a0af4SBart Van Assche if (nalloc + 1 < nalloc) 493e80a0af4SBart Van Assche return NULL; 494e80a0af4SBart Van Assche nalloc++; 495e80a0af4SBart Van Assche } 496e80a0af4SBart Van Assche sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), 497e80a0af4SBart Van Assche (gfp & ~GFP_DMA) | __GFP_ZERO); 498e80a0af4SBart Van Assche if (!sgl) 499e80a0af4SBart Van Assche return NULL; 500e80a0af4SBart Van Assche 5018c7a8d1cSBart Van Assche sg_init_table(sgl, nalloc); 502e80a0af4SBart Van Assche sg = sgl; 503e80a0af4SBart Van Assche while (length) { 504e80a0af4SBart Van Assche elem_len = min_t(u64, length, PAGE_SIZE << order); 505e80a0af4SBart Van Assche page = alloc_pages(gfp, order); 506e80a0af4SBart Van Assche if (!page) { 507e80a0af4SBart Van Assche sgl_free(sgl); 508e80a0af4SBart Van Assche return NULL; 509e80a0af4SBart Van Assche } 510e80a0af4SBart Van Assche 511e80a0af4SBart Van Assche sg_set_page(sg, page, elem_len, 0); 512e80a0af4SBart Van Assche length -= elem_len; 513e80a0af4SBart Van Assche sg = sg_next(sg); 514e80a0af4SBart Van Assche } 5158c7a8d1cSBart Van Assche WARN_ONCE(length, "length = %lld\n", length); 516e80a0af4SBart Van Assche if (nent_p) 517e80a0af4SBart Van Assche *nent_p = nent; 518e80a0af4SBart Van Assche return sgl; 519e80a0af4SBart Van Assche } 520e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc_order); 521e80a0af4SBart Van Assche 522e80a0af4SBart Van Assche /** 523e80a0af4SBart Van Assche * sgl_alloc - allocate a scatterlist and its pages 524e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist 525e80a0af4SBart Van Assche * @gfp: Memory allocation flags 526e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist 527e80a0af4SBart Van Assche * 528e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 529e80a0af4SBart Van Assche */ 530e80a0af4SBart Van Assche struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, 531e80a0af4SBart Van Assche unsigned int *nent_p) 532e80a0af4SBart Van Assche { 533e80a0af4SBart Van Assche return sgl_alloc_order(length, 0, false, gfp, nent_p); 534e80a0af4SBart Van Assche } 535e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc); 536e80a0af4SBart Van Assche 537e80a0af4SBart Van Assche /** 5388c7a8d1cSBart Van Assche * sgl_free_n_order - free a scatterlist and its pages 5398c7a8d1cSBart Van Assche * @sgl: Scatterlist with one or more elements 5408c7a8d1cSBart Van Assche * @nents: Maximum number of elements to free 5418c7a8d1cSBart Van Assche * @order: Second argument for __free_pages() 5428c7a8d1cSBart Van Assche * 5438c7a8d1cSBart Van Assche * Notes: 5448c7a8d1cSBart Van Assche * - If several scatterlists have been chained and each chain element is 5458c7a8d1cSBart Van Assche * freed separately then it's essential to set nents correctly to avoid that a 5468c7a8d1cSBart Van Assche * page would get freed twice. 5478c7a8d1cSBart Van Assche * - All pages in a chained scatterlist can be freed at once by setting @nents 5488c7a8d1cSBart Van Assche * to a high number. 5498c7a8d1cSBart Van Assche */ 5508c7a8d1cSBart Van Assche void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) 5518c7a8d1cSBart Van Assche { 5528c7a8d1cSBart Van Assche struct scatterlist *sg; 5538c7a8d1cSBart Van Assche struct page *page; 5548c7a8d1cSBart Van Assche int i; 5558c7a8d1cSBart Van Assche 5568c7a8d1cSBart Van Assche for_each_sg(sgl, sg, nents, i) { 5578c7a8d1cSBart Van Assche if (!sg) 5588c7a8d1cSBart Van Assche break; 5598c7a8d1cSBart Van Assche page = sg_page(sg); 5608c7a8d1cSBart Van Assche if (page) 5618c7a8d1cSBart Van Assche __free_pages(page, order); 5628c7a8d1cSBart Van Assche } 5638c7a8d1cSBart Van Assche kfree(sgl); 5648c7a8d1cSBart Van Assche } 5658c7a8d1cSBart Van Assche EXPORT_SYMBOL(sgl_free_n_order); 5668c7a8d1cSBart Van Assche 5678c7a8d1cSBart Van Assche /** 568e80a0af4SBart Van Assche * sgl_free_order - free a scatterlist and its pages 569e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 570e80a0af4SBart Van Assche * @order: Second argument for __free_pages() 571e80a0af4SBart Van Assche */ 572e80a0af4SBart Van Assche void sgl_free_order(struct scatterlist *sgl, int order) 573e80a0af4SBart Van Assche { 5748c7a8d1cSBart Van Assche sgl_free_n_order(sgl, INT_MAX, order); 575e80a0af4SBart Van Assche } 576e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free_order); 577e80a0af4SBart Van Assche 578e80a0af4SBart Van Assche /** 579e80a0af4SBart Van Assche * sgl_free - free a scatterlist and its pages 580e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 581e80a0af4SBart Van Assche */ 582e80a0af4SBart Van Assche void sgl_free(struct scatterlist *sgl) 583e80a0af4SBart Van Assche { 584e80a0af4SBart Van Assche sgl_free_order(sgl, 0); 585e80a0af4SBart Van Assche } 586e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free); 587e80a0af4SBart Van Assche 588e80a0af4SBart Van Assche #endif /* CONFIG_SGL_ALLOC */ 589e80a0af4SBart Van Assche 590a321e91bSImre Deak void __sg_page_iter_start(struct sg_page_iter *piter, 591a321e91bSImre Deak struct scatterlist *sglist, unsigned int nents, 592a321e91bSImre Deak unsigned long pgoffset) 593a321e91bSImre Deak { 594a321e91bSImre Deak piter->__pg_advance = 0; 595a321e91bSImre Deak piter->__nents = nents; 596a321e91bSImre Deak 597a321e91bSImre Deak piter->sg = sglist; 598a321e91bSImre Deak piter->sg_pgoffset = pgoffset; 599a321e91bSImre Deak } 600a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_start); 601a321e91bSImre Deak 602a321e91bSImre Deak static int sg_page_count(struct scatterlist *sg) 603a321e91bSImre Deak { 604a321e91bSImre Deak return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; 605a321e91bSImre Deak } 606a321e91bSImre Deak 607a321e91bSImre Deak bool __sg_page_iter_next(struct sg_page_iter *piter) 608a321e91bSImre Deak { 609a321e91bSImre Deak if (!piter->__nents || !piter->sg) 610a321e91bSImre Deak return false; 611a321e91bSImre Deak 612a321e91bSImre Deak piter->sg_pgoffset += piter->__pg_advance; 613a321e91bSImre Deak piter->__pg_advance = 1; 614a321e91bSImre Deak 615a321e91bSImre Deak while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { 616a321e91bSImre Deak piter->sg_pgoffset -= sg_page_count(piter->sg); 617a321e91bSImre Deak piter->sg = sg_next(piter->sg); 618a321e91bSImre Deak if (!--piter->__nents || !piter->sg) 619a321e91bSImre Deak return false; 620a321e91bSImre Deak } 621a321e91bSImre Deak 622a321e91bSImre Deak return true; 623a321e91bSImre Deak } 624a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_next); 625a321e91bSImre Deak 626d901b276SJason Gunthorpe static int sg_dma_page_count(struct scatterlist *sg) 627d901b276SJason Gunthorpe { 628d901b276SJason Gunthorpe return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; 629d901b276SJason Gunthorpe } 630d901b276SJason Gunthorpe 631d901b276SJason Gunthorpe bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) 632d901b276SJason Gunthorpe { 633d901b276SJason Gunthorpe struct sg_page_iter *piter = &dma_iter->base; 634d901b276SJason Gunthorpe 635d901b276SJason Gunthorpe if (!piter->__nents || !piter->sg) 636d901b276SJason Gunthorpe return false; 637d901b276SJason Gunthorpe 638d901b276SJason Gunthorpe piter->sg_pgoffset += piter->__pg_advance; 639d901b276SJason Gunthorpe piter->__pg_advance = 1; 640d901b276SJason Gunthorpe 641d901b276SJason Gunthorpe while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { 642d901b276SJason Gunthorpe piter->sg_pgoffset -= sg_dma_page_count(piter->sg); 643d901b276SJason Gunthorpe piter->sg = sg_next(piter->sg); 644d901b276SJason Gunthorpe if (!--piter->__nents || !piter->sg) 645d901b276SJason Gunthorpe return false; 646d901b276SJason Gunthorpe } 647d901b276SJason Gunthorpe 648d901b276SJason Gunthorpe return true; 649d901b276SJason Gunthorpe } 650d901b276SJason Gunthorpe EXPORT_SYMBOL(__sg_page_iter_dma_next); 651d901b276SJason Gunthorpe 652efc42bc9STomasz Stanislawski /** 653137d3edbSTejun Heo * sg_miter_start - start mapping iteration over a sg list 654137d3edbSTejun Heo * @miter: sg mapping iter to be started 655137d3edbSTejun Heo * @sgl: sg list to iterate over 656137d3edbSTejun Heo * @nents: number of sg entries 657137d3edbSTejun Heo * 658137d3edbSTejun Heo * Description: 659137d3edbSTejun Heo * Starts mapping iterator @miter. 660137d3edbSTejun Heo * 661137d3edbSTejun Heo * Context: 662137d3edbSTejun Heo * Don't care. 663137d3edbSTejun Heo */ 664137d3edbSTejun Heo void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, 665137d3edbSTejun Heo unsigned int nents, unsigned int flags) 666137d3edbSTejun Heo { 667137d3edbSTejun Heo memset(miter, 0, sizeof(struct sg_mapping_iter)); 668137d3edbSTejun Heo 6694225fc85SImre Deak __sg_page_iter_start(&miter->piter, sgl, nents, 0); 6706de7e356SSebastian Andrzej Siewior WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); 671137d3edbSTejun Heo miter->__flags = flags; 672137d3edbSTejun Heo } 673137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_start); 674137d3edbSTejun Heo 67511052004SAkinobu Mita static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) 67611052004SAkinobu Mita { 67711052004SAkinobu Mita if (!miter->__remaining) { 67811052004SAkinobu Mita struct scatterlist *sg; 67911052004SAkinobu Mita unsigned long pgoffset; 68011052004SAkinobu Mita 68111052004SAkinobu Mita if (!__sg_page_iter_next(&miter->piter)) 68211052004SAkinobu Mita return false; 68311052004SAkinobu Mita 68411052004SAkinobu Mita sg = miter->piter.sg; 68511052004SAkinobu Mita pgoffset = miter->piter.sg_pgoffset; 68611052004SAkinobu Mita 68711052004SAkinobu Mita miter->__offset = pgoffset ? 0 : sg->offset; 68811052004SAkinobu Mita miter->__remaining = sg->offset + sg->length - 68911052004SAkinobu Mita (pgoffset << PAGE_SHIFT) - miter->__offset; 69011052004SAkinobu Mita miter->__remaining = min_t(unsigned long, miter->__remaining, 69111052004SAkinobu Mita PAGE_SIZE - miter->__offset); 69211052004SAkinobu Mita } 69311052004SAkinobu Mita 69411052004SAkinobu Mita return true; 69511052004SAkinobu Mita } 69611052004SAkinobu Mita 697137d3edbSTejun Heo /** 698df642ceaSAkinobu Mita * sg_miter_skip - reposition mapping iterator 699df642ceaSAkinobu Mita * @miter: sg mapping iter to be skipped 700df642ceaSAkinobu Mita * @offset: number of bytes to plus the current location 701df642ceaSAkinobu Mita * 702df642ceaSAkinobu Mita * Description: 703df642ceaSAkinobu Mita * Sets the offset of @miter to its current location plus @offset bytes. 704df642ceaSAkinobu Mita * If mapping iterator @miter has been proceeded by sg_miter_next(), this 705df642ceaSAkinobu Mita * stops @miter. 706df642ceaSAkinobu Mita * 707df642ceaSAkinobu Mita * Context: 708df642ceaSAkinobu Mita * Don't care if @miter is stopped, or not proceeded yet. 709df642ceaSAkinobu Mita * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set. 710df642ceaSAkinobu Mita * 711df642ceaSAkinobu Mita * Returns: 712df642ceaSAkinobu Mita * true if @miter contains the valid mapping. false if end of sg 713df642ceaSAkinobu Mita * list is reached. 714df642ceaSAkinobu Mita */ 7150d6077f8SMing Lei bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) 716df642ceaSAkinobu Mita { 717df642ceaSAkinobu Mita sg_miter_stop(miter); 718df642ceaSAkinobu Mita 719df642ceaSAkinobu Mita while (offset) { 720df642ceaSAkinobu Mita off_t consumed; 721df642ceaSAkinobu Mita 722df642ceaSAkinobu Mita if (!sg_miter_get_next_page(miter)) 723df642ceaSAkinobu Mita return false; 724df642ceaSAkinobu Mita 725df642ceaSAkinobu Mita consumed = min_t(off_t, offset, miter->__remaining); 726df642ceaSAkinobu Mita miter->__offset += consumed; 727df642ceaSAkinobu Mita miter->__remaining -= consumed; 728df642ceaSAkinobu Mita offset -= consumed; 729df642ceaSAkinobu Mita } 730df642ceaSAkinobu Mita 731df642ceaSAkinobu Mita return true; 732df642ceaSAkinobu Mita } 7330d6077f8SMing Lei EXPORT_SYMBOL(sg_miter_skip); 734df642ceaSAkinobu Mita 735df642ceaSAkinobu Mita /** 736137d3edbSTejun Heo * sg_miter_next - proceed mapping iterator to the next mapping 737137d3edbSTejun Heo * @miter: sg mapping iter to proceed 738137d3edbSTejun Heo * 739137d3edbSTejun Heo * Description: 7408290e2d2STejun Heo * Proceeds @miter to the next mapping. @miter should have been started 7418290e2d2STejun Heo * using sg_miter_start(). On successful return, @miter->page, 7428290e2d2STejun Heo * @miter->addr and @miter->length point to the current mapping. 743137d3edbSTejun Heo * 744137d3edbSTejun Heo * Context: 7458290e2d2STejun Heo * Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled 7468290e2d2STejun Heo * till @miter is stopped. May sleep if !SG_MITER_ATOMIC. 747137d3edbSTejun Heo * 748137d3edbSTejun Heo * Returns: 749137d3edbSTejun Heo * true if @miter contains the next mapping. false if end of sg 750137d3edbSTejun Heo * list is reached. 751137d3edbSTejun Heo */ 752137d3edbSTejun Heo bool sg_miter_next(struct sg_mapping_iter *miter) 753137d3edbSTejun Heo { 754137d3edbSTejun Heo sg_miter_stop(miter); 755137d3edbSTejun Heo 7564225fc85SImre Deak /* 7574225fc85SImre Deak * Get to the next page if necessary. 7584225fc85SImre Deak * __remaining, __offset is adjusted by sg_miter_stop 7594225fc85SImre Deak */ 76011052004SAkinobu Mita if (!sg_miter_get_next_page(miter)) 76123c560a9STejun Heo return false; 7624225fc85SImre Deak 7632db76d7cSImre Deak miter->page = sg_page_iter_page(&miter->piter); 7644225fc85SImre Deak miter->consumed = miter->length = miter->__remaining; 765137d3edbSTejun Heo 766137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) 7674225fc85SImre Deak miter->addr = kmap_atomic(miter->page) + miter->__offset; 768137d3edbSTejun Heo else 7694225fc85SImre Deak miter->addr = kmap(miter->page) + miter->__offset; 770137d3edbSTejun Heo 771137d3edbSTejun Heo return true; 772137d3edbSTejun Heo } 773137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_next); 774137d3edbSTejun Heo 775137d3edbSTejun Heo /** 776137d3edbSTejun Heo * sg_miter_stop - stop mapping iteration 777137d3edbSTejun Heo * @miter: sg mapping iter to be stopped 778137d3edbSTejun Heo * 779137d3edbSTejun Heo * Description: 780137d3edbSTejun Heo * Stops mapping iterator @miter. @miter should have been started 7814ba6a2b2SMasahiro Yamada * using sg_miter_start(). A stopped iteration can be resumed by 7824ba6a2b2SMasahiro Yamada * calling sg_miter_next() on it. This is useful when resources (kmap) 7834ba6a2b2SMasahiro Yamada * need to be released during iteration. 784137d3edbSTejun Heo * 785137d3edbSTejun Heo * Context: 7868290e2d2STejun Heo * Preemption disabled if the SG_MITER_ATOMIC is set. Don't care 7878290e2d2STejun Heo * otherwise. 788137d3edbSTejun Heo */ 789137d3edbSTejun Heo void sg_miter_stop(struct sg_mapping_iter *miter) 790137d3edbSTejun Heo { 791137d3edbSTejun Heo WARN_ON(miter->consumed > miter->length); 792137d3edbSTejun Heo 793137d3edbSTejun Heo /* drop resources from the last iteration */ 794137d3edbSTejun Heo if (miter->addr) { 795137d3edbSTejun Heo miter->__offset += miter->consumed; 7964225fc85SImre Deak miter->__remaining -= miter->consumed; 797137d3edbSTejun Heo 7983d77b50cSMing Lei if ((miter->__flags & SG_MITER_TO_SG) && 7993d77b50cSMing Lei !PageSlab(miter->page)) 8006de7e356SSebastian Andrzej Siewior flush_kernel_dcache_page(miter->page); 8016de7e356SSebastian Andrzej Siewior 802137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) { 8038290e2d2STejun Heo WARN_ON_ONCE(preemptible()); 804c3eede8eSCong Wang kunmap_atomic(miter->addr); 805137d3edbSTejun Heo } else 806f652c521SArjan van de Ven kunmap(miter->page); 807137d3edbSTejun Heo 808137d3edbSTejun Heo miter->page = NULL; 809137d3edbSTejun Heo miter->addr = NULL; 810137d3edbSTejun Heo miter->length = 0; 811137d3edbSTejun Heo miter->consumed = 0; 812137d3edbSTejun Heo } 813137d3edbSTejun Heo } 814137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_stop); 815137d3edbSTejun Heo 816137d3edbSTejun Heo /** 817b1adaf65SFUJITA Tomonori * sg_copy_buffer - Copy data between a linear buffer and an SG list 818b1adaf65SFUJITA Tomonori * @sgl: The SG list 819b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 820b1adaf65SFUJITA Tomonori * @buf: Where to copy from 821b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 822df642ceaSAkinobu Mita * @skip: Number of bytes to skip before copying 823df642ceaSAkinobu Mita * @to_buffer: transfer direction (true == from an sg list to a 824df642ceaSAkinobu Mita * buffer, false == from a buffer to an sg list 825b1adaf65SFUJITA Tomonori * 826b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 827b1adaf65SFUJITA Tomonori * 828b1adaf65SFUJITA Tomonori **/ 829386ecb12SDave Gordon size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, 830386ecb12SDave Gordon size_t buflen, off_t skip, bool to_buffer) 831b1adaf65SFUJITA Tomonori { 832137d3edbSTejun Heo unsigned int offset = 0; 833137d3edbSTejun Heo struct sg_mapping_iter miter; 8346de7e356SSebastian Andrzej Siewior unsigned int sg_flags = SG_MITER_ATOMIC; 835b1adaf65SFUJITA Tomonori 8366de7e356SSebastian Andrzej Siewior if (to_buffer) 8376de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_FROM_SG; 8386de7e356SSebastian Andrzej Siewior else 8396de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_TO_SG; 8406de7e356SSebastian Andrzej Siewior 8416de7e356SSebastian Andrzej Siewior sg_miter_start(&miter, sgl, nents, sg_flags); 842b1adaf65SFUJITA Tomonori 843df642ceaSAkinobu Mita if (!sg_miter_skip(&miter, skip)) 844df642ceaSAkinobu Mita return false; 845df642ceaSAkinobu Mita 8461d5210efSGilad Ben-Yossef while ((offset < buflen) && sg_miter_next(&miter)) { 847137d3edbSTejun Heo unsigned int len; 848b1adaf65SFUJITA Tomonori 849137d3edbSTejun Heo len = min(miter.length, buflen - offset); 850b1adaf65SFUJITA Tomonori 851b1adaf65SFUJITA Tomonori if (to_buffer) 852137d3edbSTejun Heo memcpy(buf + offset, miter.addr, len); 8536de7e356SSebastian Andrzej Siewior else 854137d3edbSTejun Heo memcpy(miter.addr, buf + offset, len); 855b1adaf65SFUJITA Tomonori 856137d3edbSTejun Heo offset += len; 857b1adaf65SFUJITA Tomonori } 858b1adaf65SFUJITA Tomonori 859137d3edbSTejun Heo sg_miter_stop(&miter); 860b1adaf65SFUJITA Tomonori 861137d3edbSTejun Heo return offset; 862b1adaf65SFUJITA Tomonori } 863386ecb12SDave Gordon EXPORT_SYMBOL(sg_copy_buffer); 864b1adaf65SFUJITA Tomonori 865b1adaf65SFUJITA Tomonori /** 866b1adaf65SFUJITA Tomonori * sg_copy_from_buffer - Copy from a linear buffer to an SG list 867b1adaf65SFUJITA Tomonori * @sgl: The SG list 868b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 869b1adaf65SFUJITA Tomonori * @buf: Where to copy from 870b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 871b1adaf65SFUJITA Tomonori * 872b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 873b1adaf65SFUJITA Tomonori * 874b1adaf65SFUJITA Tomonori **/ 875b1adaf65SFUJITA Tomonori size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, 8762a1bf8f9SDave Gordon const void *buf, size_t buflen) 877b1adaf65SFUJITA Tomonori { 8782a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); 879b1adaf65SFUJITA Tomonori } 880b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_from_buffer); 881b1adaf65SFUJITA Tomonori 882b1adaf65SFUJITA Tomonori /** 883b1adaf65SFUJITA Tomonori * sg_copy_to_buffer - Copy from an SG list to a linear buffer 884b1adaf65SFUJITA Tomonori * @sgl: The SG list 885b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 886b1adaf65SFUJITA Tomonori * @buf: Where to copy to 887b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 888b1adaf65SFUJITA Tomonori * 889b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 890b1adaf65SFUJITA Tomonori * 891b1adaf65SFUJITA Tomonori **/ 892b1adaf65SFUJITA Tomonori size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, 893b1adaf65SFUJITA Tomonori void *buf, size_t buflen) 894b1adaf65SFUJITA Tomonori { 895df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); 896b1adaf65SFUJITA Tomonori } 897b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_to_buffer); 898df642ceaSAkinobu Mita 899df642ceaSAkinobu Mita /** 900df642ceaSAkinobu Mita * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list 901df642ceaSAkinobu Mita * @sgl: The SG list 902df642ceaSAkinobu Mita * @nents: Number of SG entries 903df642ceaSAkinobu Mita * @buf: Where to copy from 904df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 9054dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 906df642ceaSAkinobu Mita * 907df642ceaSAkinobu Mita * Returns the number of copied bytes. 908df642ceaSAkinobu Mita * 909df642ceaSAkinobu Mita **/ 910df642ceaSAkinobu Mita size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, 9112a1bf8f9SDave Gordon const void *buf, size_t buflen, off_t skip) 912df642ceaSAkinobu Mita { 9132a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); 914df642ceaSAkinobu Mita } 915df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_from_buffer); 916df642ceaSAkinobu Mita 917df642ceaSAkinobu Mita /** 918df642ceaSAkinobu Mita * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer 919df642ceaSAkinobu Mita * @sgl: The SG list 920df642ceaSAkinobu Mita * @nents: Number of SG entries 921df642ceaSAkinobu Mita * @buf: Where to copy to 922df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 9234dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 924df642ceaSAkinobu Mita * 925df642ceaSAkinobu Mita * Returns the number of copied bytes. 926df642ceaSAkinobu Mita * 927df642ceaSAkinobu Mita **/ 928df642ceaSAkinobu Mita size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, 929df642ceaSAkinobu Mita void *buf, size_t buflen, off_t skip) 930df642ceaSAkinobu Mita { 931df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); 932df642ceaSAkinobu Mita } 933df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_to_buffer); 9340945e569SJohannes Thumshirn 9350945e569SJohannes Thumshirn /** 9360945e569SJohannes Thumshirn * sg_zero_buffer - Zero-out a part of a SG list 9370945e569SJohannes Thumshirn * @sgl: The SG list 9380945e569SJohannes Thumshirn * @nents: Number of SG entries 9390945e569SJohannes Thumshirn * @buflen: The number of bytes to zero out 9400945e569SJohannes Thumshirn * @skip: Number of bytes to skip before zeroing 9410945e569SJohannes Thumshirn * 9420945e569SJohannes Thumshirn * Returns the number of bytes zeroed. 9430945e569SJohannes Thumshirn **/ 9440945e569SJohannes Thumshirn size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, 9450945e569SJohannes Thumshirn size_t buflen, off_t skip) 9460945e569SJohannes Thumshirn { 9470945e569SJohannes Thumshirn unsigned int offset = 0; 9480945e569SJohannes Thumshirn struct sg_mapping_iter miter; 9490945e569SJohannes Thumshirn unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; 9500945e569SJohannes Thumshirn 9510945e569SJohannes Thumshirn sg_miter_start(&miter, sgl, nents, sg_flags); 9520945e569SJohannes Thumshirn 9530945e569SJohannes Thumshirn if (!sg_miter_skip(&miter, skip)) 9540945e569SJohannes Thumshirn return false; 9550945e569SJohannes Thumshirn 9560945e569SJohannes Thumshirn while (offset < buflen && sg_miter_next(&miter)) { 9570945e569SJohannes Thumshirn unsigned int len; 9580945e569SJohannes Thumshirn 9590945e569SJohannes Thumshirn len = min(miter.length, buflen - offset); 9600945e569SJohannes Thumshirn memset(miter.addr, 0, len); 9610945e569SJohannes Thumshirn 9620945e569SJohannes Thumshirn offset += len; 9630945e569SJohannes Thumshirn } 9640945e569SJohannes Thumshirn 9650945e569SJohannes Thumshirn sg_miter_stop(&miter); 9660945e569SJohannes Thumshirn return offset; 9670945e569SJohannes Thumshirn } 9680945e569SJohannes Thumshirn EXPORT_SYMBOL(sg_zero_buffer); 969