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 1824635873cSMing Lei * @nents_first_chunk: Number of entries int the (preallocated) first 1834635873cSMing Lei * scatterlist chunk, 0 means no such preallocated first chunk 1840db9299fSJens Axboe * @free_fn: Free function 1850db9299fSJens Axboe * 1860db9299fSJens Axboe * Description: 1877cedb1f1SJames Bottomley * Free an sg table previously allocated and setup with 1887cedb1f1SJames Bottomley * __sg_alloc_table(). The @max_ents value must be identical to 1897cedb1f1SJames Bottomley * that previously used with __sg_alloc_table(). 1900db9299fSJens Axboe * 1910db9299fSJens Axboe **/ 1927cedb1f1SJames Bottomley void __sg_free_table(struct sg_table *table, unsigned int max_ents, 1934635873cSMing Lei unsigned int nents_first_chunk, sg_free_fn *free_fn) 1940db9299fSJens Axboe { 1950db9299fSJens Axboe struct scatterlist *sgl, *next; 1964635873cSMing Lei unsigned curr_max_ents = nents_first_chunk ?: max_ents; 1970db9299fSJens Axboe 1980db9299fSJens Axboe if (unlikely(!table->sgl)) 1990db9299fSJens Axboe return; 2000db9299fSJens Axboe 2010db9299fSJens Axboe sgl = table->sgl; 2020db9299fSJens Axboe while (table->orig_nents) { 2030db9299fSJens Axboe unsigned int alloc_size = table->orig_nents; 2040db9299fSJens Axboe unsigned int sg_size; 2050db9299fSJens Axboe 2060db9299fSJens Axboe /* 2077cedb1f1SJames Bottomley * If we have more than max_ents segments left, 2080db9299fSJens Axboe * then assign 'next' to the sg table after the current one. 2090db9299fSJens Axboe * sg_size is then one less than alloc size, since the last 2100db9299fSJens Axboe * element is the chain pointer. 2110db9299fSJens Axboe */ 2124635873cSMing Lei if (alloc_size > curr_max_ents) { 2134635873cSMing Lei next = sg_chain_ptr(&sgl[curr_max_ents - 1]); 2144635873cSMing Lei alloc_size = curr_max_ents; 2150db9299fSJens Axboe sg_size = alloc_size - 1; 2160db9299fSJens Axboe } else { 2170db9299fSJens Axboe sg_size = alloc_size; 2180db9299fSJens Axboe next = NULL; 2190db9299fSJens Axboe } 2200db9299fSJens Axboe 2210db9299fSJens Axboe table->orig_nents -= sg_size; 2224635873cSMing Lei if (nents_first_chunk) 2234635873cSMing Lei nents_first_chunk = 0; 224c21e59d8STony Battersby else 225c21e59d8STony Battersby free_fn(sgl, alloc_size); 2260db9299fSJens Axboe sgl = next; 2274635873cSMing Lei curr_max_ents = max_ents; 2280db9299fSJens Axboe } 2290db9299fSJens Axboe 2300db9299fSJens Axboe table->sgl = NULL; 2310db9299fSJens Axboe } 2320db9299fSJens Axboe EXPORT_SYMBOL(__sg_free_table); 2330db9299fSJens Axboe 2340db9299fSJens Axboe /** 2350db9299fSJens Axboe * sg_free_table - Free a previously allocated sg table 2360db9299fSJens Axboe * @table: The mapped sg table header 2370db9299fSJens Axboe * 2380db9299fSJens Axboe **/ 2390db9299fSJens Axboe void sg_free_table(struct sg_table *table) 2400db9299fSJens Axboe { 241c53c6d6aSChristoph Hellwig __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree); 2420db9299fSJens Axboe } 2430db9299fSJens Axboe EXPORT_SYMBOL(sg_free_table); 2440db9299fSJens Axboe 2450db9299fSJens Axboe /** 2460db9299fSJens Axboe * __sg_alloc_table - Allocate and initialize an sg table with given allocator 2470db9299fSJens Axboe * @table: The sg table header to use 2480db9299fSJens Axboe * @nents: Number of entries in sg list 2497cedb1f1SJames Bottomley * @max_ents: The maximum number of entries the allocator returns per call 2504635873cSMing Lei * @nents_first_chunk: Number of entries int the (preallocated) first 2514635873cSMing Lei * scatterlist chunk, 0 means no such preallocated chunk provided by user 2520db9299fSJens Axboe * @gfp_mask: GFP allocation mask 2530db9299fSJens Axboe * @alloc_fn: Allocator to use 2540db9299fSJens Axboe * 2557cedb1f1SJames Bottomley * Description: 2567cedb1f1SJames Bottomley * This function returns a @table @nents long. The allocator is 2577cedb1f1SJames Bottomley * defined to return scatterlist chunks of maximum size @max_ents. 2587cedb1f1SJames Bottomley * Thus if @nents is bigger than @max_ents, the scatterlists will be 2597cedb1f1SJames Bottomley * chained in units of @max_ents. 2607cedb1f1SJames Bottomley * 2610db9299fSJens Axboe * Notes: 2620db9299fSJens Axboe * If this function returns non-0 (eg failure), the caller must call 2630db9299fSJens Axboe * __sg_free_table() to cleanup any leftover allocations. 2640db9299fSJens Axboe * 2650db9299fSJens Axboe **/ 2667cedb1f1SJames Bottomley int __sg_alloc_table(struct sg_table *table, unsigned int nents, 267c53c6d6aSChristoph Hellwig unsigned int max_ents, struct scatterlist *first_chunk, 2684635873cSMing Lei unsigned int nents_first_chunk, gfp_t gfp_mask, 2694635873cSMing Lei sg_alloc_fn *alloc_fn) 2700db9299fSJens Axboe { 2710db9299fSJens Axboe struct scatterlist *sg, *prv; 2720db9299fSJens Axboe unsigned int left; 2734635873cSMing Lei unsigned curr_max_ents = nents_first_chunk ?: max_ents; 2744635873cSMing Lei unsigned prv_max_ents; 2750db9299fSJens Axboe 27627daabd9SDan Carpenter memset(table, 0, sizeof(*table)); 27727daabd9SDan Carpenter 27827daabd9SDan Carpenter if (nents == 0) 27927daabd9SDan Carpenter return -EINVAL; 2807c703e54SChristoph Hellwig #ifdef CONFIG_ARCH_NO_SG_CHAIN 2816fd59a83SNick Bowler if (WARN_ON_ONCE(nents > max_ents)) 2826fd59a83SNick Bowler return -EINVAL; 2830db9299fSJens Axboe #endif 2840db9299fSJens Axboe 2850db9299fSJens Axboe left = nents; 2860db9299fSJens Axboe prv = NULL; 2870db9299fSJens Axboe do { 2880db9299fSJens Axboe unsigned int sg_size, alloc_size = left; 2890db9299fSJens Axboe 2904635873cSMing Lei if (alloc_size > curr_max_ents) { 2914635873cSMing Lei alloc_size = curr_max_ents; 2920db9299fSJens Axboe sg_size = alloc_size - 1; 2930db9299fSJens Axboe } else 2940db9299fSJens Axboe sg_size = alloc_size; 2950db9299fSJens Axboe 2960db9299fSJens Axboe left -= sg_size; 2970db9299fSJens Axboe 298c53c6d6aSChristoph Hellwig if (first_chunk) { 299c53c6d6aSChristoph Hellwig sg = first_chunk; 300c53c6d6aSChristoph Hellwig first_chunk = NULL; 301c53c6d6aSChristoph Hellwig } else { 3020db9299fSJens Axboe sg = alloc_fn(alloc_size, gfp_mask); 303c53c6d6aSChristoph Hellwig } 304edce6820SJeffrey Carlyle if (unlikely(!sg)) { 305edce6820SJeffrey Carlyle /* 306edce6820SJeffrey Carlyle * Adjust entry count to reflect that the last 307edce6820SJeffrey Carlyle * entry of the previous table won't be used for 308edce6820SJeffrey Carlyle * linkage. Without this, sg_kfree() may get 309edce6820SJeffrey Carlyle * confused. 310edce6820SJeffrey Carlyle */ 311edce6820SJeffrey Carlyle if (prv) 312edce6820SJeffrey Carlyle table->nents = ++table->orig_nents; 313edce6820SJeffrey Carlyle 3140db9299fSJens Axboe return -ENOMEM; 315edce6820SJeffrey Carlyle } 3160db9299fSJens Axboe 3170db9299fSJens Axboe sg_init_table(sg, alloc_size); 3180db9299fSJens Axboe table->nents = table->orig_nents += sg_size; 3190db9299fSJens Axboe 3200db9299fSJens Axboe /* 3210db9299fSJens Axboe * If this is the first mapping, assign the sg table header. 3220db9299fSJens Axboe * If this is not the first mapping, chain previous part. 3230db9299fSJens Axboe */ 3240db9299fSJens Axboe if (prv) 3254635873cSMing Lei sg_chain(prv, prv_max_ents, sg); 3260db9299fSJens Axboe else 3270db9299fSJens Axboe table->sgl = sg; 3280db9299fSJens Axboe 3290db9299fSJens Axboe /* 3300db9299fSJens Axboe * If no more entries after this one, mark the end 3310db9299fSJens Axboe */ 3320db9299fSJens Axboe if (!left) 3330db9299fSJens Axboe sg_mark_end(&sg[sg_size - 1]); 3340db9299fSJens Axboe 3350db9299fSJens Axboe prv = sg; 3364635873cSMing Lei prv_max_ents = curr_max_ents; 3374635873cSMing Lei curr_max_ents = max_ents; 3380db9299fSJens Axboe } while (left); 3390db9299fSJens Axboe 3400db9299fSJens Axboe return 0; 3410db9299fSJens Axboe } 3420db9299fSJens Axboe EXPORT_SYMBOL(__sg_alloc_table); 3430db9299fSJens Axboe 3440db9299fSJens Axboe /** 3450db9299fSJens Axboe * sg_alloc_table - Allocate and initialize an sg table 3460db9299fSJens Axboe * @table: The sg table header to use 3470db9299fSJens Axboe * @nents: Number of entries in sg list 3480db9299fSJens Axboe * @gfp_mask: GFP allocation mask 3490db9299fSJens Axboe * 3500db9299fSJens Axboe * Description: 3510db9299fSJens Axboe * Allocate and initialize an sg table. If @nents@ is larger than 3520db9299fSJens Axboe * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. 3530db9299fSJens Axboe * 3540db9299fSJens Axboe **/ 3550db9299fSJens Axboe int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) 3560db9299fSJens Axboe { 3570db9299fSJens Axboe int ret; 3580db9299fSJens Axboe 3597cedb1f1SJames Bottomley ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, 3604635873cSMing Lei NULL, 0, gfp_mask, sg_kmalloc); 3610db9299fSJens Axboe if (unlikely(ret)) 3624635873cSMing Lei __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); 3630db9299fSJens Axboe 3640db9299fSJens Axboe return ret; 3650db9299fSJens Axboe } 3660db9299fSJens Axboe EXPORT_SYMBOL(sg_alloc_table); 367b1adaf65SFUJITA Tomonori 368b1adaf65SFUJITA Tomonori /** 36989d8589cSTvrtko Ursulin * __sg_alloc_table_from_pages - Allocate and initialize an sg table from 370efc42bc9STomasz Stanislawski * an array of pages 371efc42bc9STomasz Stanislawski * @sgt: The sg table header to use 372efc42bc9STomasz Stanislawski * @pages: Pointer to an array of page pointers 373efc42bc9STomasz Stanislawski * @n_pages: Number of pages in the pages array 374efc42bc9STomasz Stanislawski * @offset: Offset from start of the first page to the start of a buffer 375efc42bc9STomasz Stanislawski * @size: Number of valid bytes in the buffer (after offset) 37689d8589cSTvrtko Ursulin * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) 377efc42bc9STomasz Stanislawski * @gfp_mask: GFP allocation mask 378efc42bc9STomasz Stanislawski * 379efc42bc9STomasz Stanislawski * Description: 380efc42bc9STomasz Stanislawski * Allocate and initialize an sg table from a list of pages. Contiguous 38189d8589cSTvrtko Ursulin * ranges of the pages are squashed into a single scatterlist node up to the 38289d8589cSTvrtko Ursulin * maximum size specified in @max_segment. An user may provide an offset at a 38389d8589cSTvrtko Ursulin * start and a size of valid data in a buffer specified by the page array. 38489d8589cSTvrtko Ursulin * The returned sg table is released by sg_free_table. 385efc42bc9STomasz Stanislawski * 386efc42bc9STomasz Stanislawski * Returns: 387efc42bc9STomasz Stanislawski * 0 on success, negative error on failure 388efc42bc9STomasz Stanislawski */ 38989d8589cSTvrtko Ursulin int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, 39089d8589cSTvrtko Ursulin unsigned int n_pages, unsigned int offset, 39189d8589cSTvrtko Ursulin unsigned long size, unsigned int max_segment, 392efc42bc9STomasz Stanislawski gfp_t gfp_mask) 393efc42bc9STomasz Stanislawski { 394c125906bSTvrtko Ursulin unsigned int chunks, cur_page, seg_len, i; 395efc42bc9STomasz Stanislawski int ret; 396efc42bc9STomasz Stanislawski struct scatterlist *s; 397efc42bc9STomasz Stanislawski 39889d8589cSTvrtko Ursulin if (WARN_ON(!max_segment || offset_in_page(max_segment))) 39989d8589cSTvrtko Ursulin return -EINVAL; 40089d8589cSTvrtko Ursulin 401efc42bc9STomasz Stanislawski /* compute number of contiguous chunks */ 402efc42bc9STomasz Stanislawski chunks = 1; 403c125906bSTvrtko Ursulin seg_len = 0; 404c125906bSTvrtko Ursulin for (i = 1; i < n_pages; i++) { 405c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 406c125906bSTvrtko Ursulin if (seg_len >= max_segment || 407c125906bSTvrtko Ursulin page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { 408c125906bSTvrtko Ursulin chunks++; 409c125906bSTvrtko Ursulin seg_len = 0; 410c125906bSTvrtko Ursulin } 411c125906bSTvrtko Ursulin } 412efc42bc9STomasz Stanislawski 413efc42bc9STomasz Stanislawski ret = sg_alloc_table(sgt, chunks, gfp_mask); 414efc42bc9STomasz Stanislawski if (unlikely(ret)) 415efc42bc9STomasz Stanislawski return ret; 416efc42bc9STomasz Stanislawski 417efc42bc9STomasz Stanislawski /* merging chunks and putting them into the scatterlist */ 418efc42bc9STomasz Stanislawski cur_page = 0; 419efc42bc9STomasz Stanislawski for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { 420c125906bSTvrtko Ursulin unsigned int j, chunk_size; 421efc42bc9STomasz Stanislawski 422efc42bc9STomasz Stanislawski /* look for the end of the current chunk */ 423c125906bSTvrtko Ursulin seg_len = 0; 424c125906bSTvrtko Ursulin for (j = cur_page + 1; j < n_pages; j++) { 425c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 426c125906bSTvrtko Ursulin if (seg_len >= max_segment || 427c125906bSTvrtko Ursulin page_to_pfn(pages[j]) != 428efc42bc9STomasz Stanislawski page_to_pfn(pages[j - 1]) + 1) 429efc42bc9STomasz Stanislawski break; 430c125906bSTvrtko Ursulin } 431efc42bc9STomasz Stanislawski 432efc42bc9STomasz Stanislawski chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; 433c125906bSTvrtko Ursulin sg_set_page(s, pages[cur_page], 434c125906bSTvrtko Ursulin min_t(unsigned long, size, chunk_size), offset); 435efc42bc9STomasz Stanislawski size -= chunk_size; 436efc42bc9STomasz Stanislawski offset = 0; 437efc42bc9STomasz Stanislawski cur_page = j; 438efc42bc9STomasz Stanislawski } 439efc42bc9STomasz Stanislawski 440efc42bc9STomasz Stanislawski return 0; 441efc42bc9STomasz Stanislawski } 44289d8589cSTvrtko Ursulin EXPORT_SYMBOL(__sg_alloc_table_from_pages); 44389d8589cSTvrtko Ursulin 44489d8589cSTvrtko Ursulin /** 44589d8589cSTvrtko Ursulin * sg_alloc_table_from_pages - Allocate and initialize an sg table from 44689d8589cSTvrtko Ursulin * an array of pages 44789d8589cSTvrtko Ursulin * @sgt: The sg table header to use 44889d8589cSTvrtko Ursulin * @pages: Pointer to an array of page pointers 44989d8589cSTvrtko Ursulin * @n_pages: Number of pages in the pages array 45089d8589cSTvrtko Ursulin * @offset: Offset from start of the first page to the start of a buffer 45189d8589cSTvrtko Ursulin * @size: Number of valid bytes in the buffer (after offset) 45289d8589cSTvrtko Ursulin * @gfp_mask: GFP allocation mask 45389d8589cSTvrtko Ursulin * 45489d8589cSTvrtko Ursulin * Description: 45589d8589cSTvrtko Ursulin * Allocate and initialize an sg table from a list of pages. Contiguous 45689d8589cSTvrtko Ursulin * ranges of the pages are squashed into a single scatterlist node. A user 45789d8589cSTvrtko Ursulin * may provide an offset at a start and a size of valid data in a buffer 45889d8589cSTvrtko Ursulin * specified by the page array. The returned sg table is released by 45989d8589cSTvrtko Ursulin * sg_free_table. 46089d8589cSTvrtko Ursulin * 46189d8589cSTvrtko Ursulin * Returns: 46289d8589cSTvrtko Ursulin * 0 on success, negative error on failure 46389d8589cSTvrtko Ursulin */ 46489d8589cSTvrtko Ursulin int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, 46589d8589cSTvrtko Ursulin unsigned int n_pages, unsigned int offset, 46689d8589cSTvrtko Ursulin unsigned long size, gfp_t gfp_mask) 46789d8589cSTvrtko Ursulin { 46889d8589cSTvrtko Ursulin return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, 46989d8589cSTvrtko Ursulin SCATTERLIST_MAX_SEGMENT, gfp_mask); 47089d8589cSTvrtko Ursulin } 471efc42bc9STomasz Stanislawski EXPORT_SYMBOL(sg_alloc_table_from_pages); 472efc42bc9STomasz Stanislawski 473e80a0af4SBart Van Assche #ifdef CONFIG_SGL_ALLOC 474e80a0af4SBart Van Assche 475e80a0af4SBart Van Assche /** 476e80a0af4SBart Van Assche * sgl_alloc_order - allocate a scatterlist and its pages 477e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist. Must be at least one 478e80a0af4SBart Van Assche * @order: Second argument for alloc_pages() 479e80a0af4SBart Van Assche * @chainable: Whether or not to allocate an extra element in the scatterlist 480e80a0af4SBart Van Assche * for scatterlist chaining purposes 481e80a0af4SBart Van Assche * @gfp: Memory allocation flags 482e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist that have pages 483e80a0af4SBart Van Assche * 484e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 485e80a0af4SBart Van Assche */ 486e80a0af4SBart Van Assche struct scatterlist *sgl_alloc_order(unsigned long long length, 487e80a0af4SBart Van Assche unsigned int order, bool chainable, 488e80a0af4SBart Van Assche gfp_t gfp, unsigned int *nent_p) 489e80a0af4SBart Van Assche { 490e80a0af4SBart Van Assche struct scatterlist *sgl, *sg; 491e80a0af4SBart Van Assche struct page *page; 492e80a0af4SBart Van Assche unsigned int nent, nalloc; 493e80a0af4SBart Van Assche u32 elem_len; 494e80a0af4SBart Van Assche 495e80a0af4SBart Van Assche nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); 496e80a0af4SBart Van Assche /* Check for integer overflow */ 497e80a0af4SBart Van Assche if (length > (nent << (PAGE_SHIFT + order))) 498e80a0af4SBart Van Assche return NULL; 499e80a0af4SBart Van Assche nalloc = nent; 500e80a0af4SBart Van Assche if (chainable) { 501e80a0af4SBart Van Assche /* Check for integer overflow */ 502e80a0af4SBart Van Assche if (nalloc + 1 < nalloc) 503e80a0af4SBart Van Assche return NULL; 504e80a0af4SBart Van Assche nalloc++; 505e80a0af4SBart Van Assche } 506e80a0af4SBart Van Assche sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), 507e80a0af4SBart Van Assche (gfp & ~GFP_DMA) | __GFP_ZERO); 508e80a0af4SBart Van Assche if (!sgl) 509e80a0af4SBart Van Assche return NULL; 510e80a0af4SBart Van Assche 5118c7a8d1cSBart Van Assche sg_init_table(sgl, nalloc); 512e80a0af4SBart Van Assche sg = sgl; 513e80a0af4SBart Van Assche while (length) { 514e80a0af4SBart Van Assche elem_len = min_t(u64, length, PAGE_SIZE << order); 515e80a0af4SBart Van Assche page = alloc_pages(gfp, order); 516e80a0af4SBart Van Assche if (!page) { 517e80a0af4SBart Van Assche sgl_free(sgl); 518e80a0af4SBart Van Assche return NULL; 519e80a0af4SBart Van Assche } 520e80a0af4SBart Van Assche 521e80a0af4SBart Van Assche sg_set_page(sg, page, elem_len, 0); 522e80a0af4SBart Van Assche length -= elem_len; 523e80a0af4SBart Van Assche sg = sg_next(sg); 524e80a0af4SBart Van Assche } 5258c7a8d1cSBart Van Assche WARN_ONCE(length, "length = %lld\n", length); 526e80a0af4SBart Van Assche if (nent_p) 527e80a0af4SBart Van Assche *nent_p = nent; 528e80a0af4SBart Van Assche return sgl; 529e80a0af4SBart Van Assche } 530e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc_order); 531e80a0af4SBart Van Assche 532e80a0af4SBart Van Assche /** 533e80a0af4SBart Van Assche * sgl_alloc - allocate a scatterlist and its pages 534e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist 535e80a0af4SBart Van Assche * @gfp: Memory allocation flags 536e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist 537e80a0af4SBart Van Assche * 538e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 539e80a0af4SBart Van Assche */ 540e80a0af4SBart Van Assche struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, 541e80a0af4SBart Van Assche unsigned int *nent_p) 542e80a0af4SBart Van Assche { 543e80a0af4SBart Van Assche return sgl_alloc_order(length, 0, false, gfp, nent_p); 544e80a0af4SBart Van Assche } 545e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc); 546e80a0af4SBart Van Assche 547e80a0af4SBart Van Assche /** 5488c7a8d1cSBart Van Assche * sgl_free_n_order - free a scatterlist and its pages 5498c7a8d1cSBart Van Assche * @sgl: Scatterlist with one or more elements 5508c7a8d1cSBart Van Assche * @nents: Maximum number of elements to free 5518c7a8d1cSBart Van Assche * @order: Second argument for __free_pages() 5528c7a8d1cSBart Van Assche * 5538c7a8d1cSBart Van Assche * Notes: 5548c7a8d1cSBart Van Assche * - If several scatterlists have been chained and each chain element is 5558c7a8d1cSBart Van Assche * freed separately then it's essential to set nents correctly to avoid that a 5568c7a8d1cSBart Van Assche * page would get freed twice. 5578c7a8d1cSBart Van Assche * - All pages in a chained scatterlist can be freed at once by setting @nents 5588c7a8d1cSBart Van Assche * to a high number. 5598c7a8d1cSBart Van Assche */ 5608c7a8d1cSBart Van Assche void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) 5618c7a8d1cSBart Van Assche { 5628c7a8d1cSBart Van Assche struct scatterlist *sg; 5638c7a8d1cSBart Van Assche struct page *page; 5648c7a8d1cSBart Van Assche int i; 5658c7a8d1cSBart Van Assche 5668c7a8d1cSBart Van Assche for_each_sg(sgl, sg, nents, i) { 5678c7a8d1cSBart Van Assche if (!sg) 5688c7a8d1cSBart Van Assche break; 5698c7a8d1cSBart Van Assche page = sg_page(sg); 5708c7a8d1cSBart Van Assche if (page) 5718c7a8d1cSBart Van Assche __free_pages(page, order); 5728c7a8d1cSBart Van Assche } 5738c7a8d1cSBart Van Assche kfree(sgl); 5748c7a8d1cSBart Van Assche } 5758c7a8d1cSBart Van Assche EXPORT_SYMBOL(sgl_free_n_order); 5768c7a8d1cSBart Van Assche 5778c7a8d1cSBart Van Assche /** 578e80a0af4SBart Van Assche * sgl_free_order - free a scatterlist and its pages 579e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 580e80a0af4SBart Van Assche * @order: Second argument for __free_pages() 581e80a0af4SBart Van Assche */ 582e80a0af4SBart Van Assche void sgl_free_order(struct scatterlist *sgl, int order) 583e80a0af4SBart Van Assche { 5848c7a8d1cSBart Van Assche sgl_free_n_order(sgl, INT_MAX, order); 585e80a0af4SBart Van Assche } 586e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free_order); 587e80a0af4SBart Van Assche 588e80a0af4SBart Van Assche /** 589e80a0af4SBart Van Assche * sgl_free - free a scatterlist and its pages 590e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 591e80a0af4SBart Van Assche */ 592e80a0af4SBart Van Assche void sgl_free(struct scatterlist *sgl) 593e80a0af4SBart Van Assche { 594e80a0af4SBart Van Assche sgl_free_order(sgl, 0); 595e80a0af4SBart Van Assche } 596e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free); 597e80a0af4SBart Van Assche 598e80a0af4SBart Van Assche #endif /* CONFIG_SGL_ALLOC */ 599e80a0af4SBart Van Assche 600a321e91bSImre Deak void __sg_page_iter_start(struct sg_page_iter *piter, 601a321e91bSImre Deak struct scatterlist *sglist, unsigned int nents, 602a321e91bSImre Deak unsigned long pgoffset) 603a321e91bSImre Deak { 604a321e91bSImre Deak piter->__pg_advance = 0; 605a321e91bSImre Deak piter->__nents = nents; 606a321e91bSImre Deak 607a321e91bSImre Deak piter->sg = sglist; 608a321e91bSImre Deak piter->sg_pgoffset = pgoffset; 609a321e91bSImre Deak } 610a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_start); 611a321e91bSImre Deak 612a321e91bSImre Deak static int sg_page_count(struct scatterlist *sg) 613a321e91bSImre Deak { 614a321e91bSImre Deak return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; 615a321e91bSImre Deak } 616a321e91bSImre Deak 617a321e91bSImre Deak bool __sg_page_iter_next(struct sg_page_iter *piter) 618a321e91bSImre Deak { 619a321e91bSImre Deak if (!piter->__nents || !piter->sg) 620a321e91bSImre Deak return false; 621a321e91bSImre Deak 622a321e91bSImre Deak piter->sg_pgoffset += piter->__pg_advance; 623a321e91bSImre Deak piter->__pg_advance = 1; 624a321e91bSImre Deak 625a321e91bSImre Deak while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { 626a321e91bSImre Deak piter->sg_pgoffset -= sg_page_count(piter->sg); 627a321e91bSImre Deak piter->sg = sg_next(piter->sg); 628a321e91bSImre Deak if (!--piter->__nents || !piter->sg) 629a321e91bSImre Deak return false; 630a321e91bSImre Deak } 631a321e91bSImre Deak 632a321e91bSImre Deak return true; 633a321e91bSImre Deak } 634a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_next); 635a321e91bSImre Deak 636d901b276SJason Gunthorpe static int sg_dma_page_count(struct scatterlist *sg) 637d901b276SJason Gunthorpe { 638d901b276SJason Gunthorpe return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; 639d901b276SJason Gunthorpe } 640d901b276SJason Gunthorpe 641d901b276SJason Gunthorpe bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) 642d901b276SJason Gunthorpe { 643d901b276SJason Gunthorpe struct sg_page_iter *piter = &dma_iter->base; 644d901b276SJason Gunthorpe 645d901b276SJason Gunthorpe if (!piter->__nents || !piter->sg) 646d901b276SJason Gunthorpe return false; 647d901b276SJason Gunthorpe 648d901b276SJason Gunthorpe piter->sg_pgoffset += piter->__pg_advance; 649d901b276SJason Gunthorpe piter->__pg_advance = 1; 650d901b276SJason Gunthorpe 651d901b276SJason Gunthorpe while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { 652d901b276SJason Gunthorpe piter->sg_pgoffset -= sg_dma_page_count(piter->sg); 653d901b276SJason Gunthorpe piter->sg = sg_next(piter->sg); 654d901b276SJason Gunthorpe if (!--piter->__nents || !piter->sg) 655d901b276SJason Gunthorpe return false; 656d901b276SJason Gunthorpe } 657d901b276SJason Gunthorpe 658d901b276SJason Gunthorpe return true; 659d901b276SJason Gunthorpe } 660d901b276SJason Gunthorpe EXPORT_SYMBOL(__sg_page_iter_dma_next); 661d901b276SJason Gunthorpe 662efc42bc9STomasz Stanislawski /** 663137d3edbSTejun Heo * sg_miter_start - start mapping iteration over a sg list 664137d3edbSTejun Heo * @miter: sg mapping iter to be started 665137d3edbSTejun Heo * @sgl: sg list to iterate over 666137d3edbSTejun Heo * @nents: number of sg entries 667137d3edbSTejun Heo * 668137d3edbSTejun Heo * Description: 669137d3edbSTejun Heo * Starts mapping iterator @miter. 670137d3edbSTejun Heo * 671137d3edbSTejun Heo * Context: 672137d3edbSTejun Heo * Don't care. 673137d3edbSTejun Heo */ 674137d3edbSTejun Heo void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, 675137d3edbSTejun Heo unsigned int nents, unsigned int flags) 676137d3edbSTejun Heo { 677137d3edbSTejun Heo memset(miter, 0, sizeof(struct sg_mapping_iter)); 678137d3edbSTejun Heo 6794225fc85SImre Deak __sg_page_iter_start(&miter->piter, sgl, nents, 0); 6806de7e356SSebastian Andrzej Siewior WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); 681137d3edbSTejun Heo miter->__flags = flags; 682137d3edbSTejun Heo } 683137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_start); 684137d3edbSTejun Heo 68511052004SAkinobu Mita static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) 68611052004SAkinobu Mita { 68711052004SAkinobu Mita if (!miter->__remaining) { 68811052004SAkinobu Mita struct scatterlist *sg; 68911052004SAkinobu Mita 69011052004SAkinobu Mita if (!__sg_page_iter_next(&miter->piter)) 69111052004SAkinobu Mita return false; 69211052004SAkinobu Mita 69311052004SAkinobu Mita sg = miter->piter.sg; 69411052004SAkinobu Mita 695aeb87246SChristophe Leroy miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset; 696aeb87246SChristophe Leroy miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT; 697aeb87246SChristophe Leroy miter->__offset &= PAGE_SIZE - 1; 69811052004SAkinobu Mita miter->__remaining = sg->offset + sg->length - 699aeb87246SChristophe Leroy (miter->piter.sg_pgoffset << PAGE_SHIFT) - 700aeb87246SChristophe Leroy miter->__offset; 70111052004SAkinobu Mita miter->__remaining = min_t(unsigned long, miter->__remaining, 70211052004SAkinobu Mita PAGE_SIZE - miter->__offset); 70311052004SAkinobu Mita } 70411052004SAkinobu Mita 70511052004SAkinobu Mita return true; 70611052004SAkinobu Mita } 70711052004SAkinobu Mita 708137d3edbSTejun Heo /** 709df642ceaSAkinobu Mita * sg_miter_skip - reposition mapping iterator 710df642ceaSAkinobu Mita * @miter: sg mapping iter to be skipped 711df642ceaSAkinobu Mita * @offset: number of bytes to plus the current location 712df642ceaSAkinobu Mita * 713df642ceaSAkinobu Mita * Description: 714df642ceaSAkinobu Mita * Sets the offset of @miter to its current location plus @offset bytes. 715df642ceaSAkinobu Mita * If mapping iterator @miter has been proceeded by sg_miter_next(), this 716df642ceaSAkinobu Mita * stops @miter. 717df642ceaSAkinobu Mita * 718df642ceaSAkinobu Mita * Context: 719df642ceaSAkinobu Mita * Don't care if @miter is stopped, or not proceeded yet. 720df642ceaSAkinobu Mita * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set. 721df642ceaSAkinobu Mita * 722df642ceaSAkinobu Mita * Returns: 723df642ceaSAkinobu Mita * true if @miter contains the valid mapping. false if end of sg 724df642ceaSAkinobu Mita * list is reached. 725df642ceaSAkinobu Mita */ 7260d6077f8SMing Lei bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) 727df642ceaSAkinobu Mita { 728df642ceaSAkinobu Mita sg_miter_stop(miter); 729df642ceaSAkinobu Mita 730df642ceaSAkinobu Mita while (offset) { 731df642ceaSAkinobu Mita off_t consumed; 732df642ceaSAkinobu Mita 733df642ceaSAkinobu Mita if (!sg_miter_get_next_page(miter)) 734df642ceaSAkinobu Mita return false; 735df642ceaSAkinobu Mita 736df642ceaSAkinobu Mita consumed = min_t(off_t, offset, miter->__remaining); 737df642ceaSAkinobu Mita miter->__offset += consumed; 738df642ceaSAkinobu Mita miter->__remaining -= consumed; 739df642ceaSAkinobu Mita offset -= consumed; 740df642ceaSAkinobu Mita } 741df642ceaSAkinobu Mita 742df642ceaSAkinobu Mita return true; 743df642ceaSAkinobu Mita } 7440d6077f8SMing Lei EXPORT_SYMBOL(sg_miter_skip); 745df642ceaSAkinobu Mita 746df642ceaSAkinobu Mita /** 747137d3edbSTejun Heo * sg_miter_next - proceed mapping iterator to the next mapping 748137d3edbSTejun Heo * @miter: sg mapping iter to proceed 749137d3edbSTejun Heo * 750137d3edbSTejun Heo * Description: 7518290e2d2STejun Heo * Proceeds @miter to the next mapping. @miter should have been started 7528290e2d2STejun Heo * using sg_miter_start(). On successful return, @miter->page, 7538290e2d2STejun Heo * @miter->addr and @miter->length point to the current mapping. 754137d3edbSTejun Heo * 755137d3edbSTejun Heo * Context: 7568290e2d2STejun Heo * Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled 7578290e2d2STejun Heo * till @miter is stopped. May sleep if !SG_MITER_ATOMIC. 758137d3edbSTejun Heo * 759137d3edbSTejun Heo * Returns: 760137d3edbSTejun Heo * true if @miter contains the next mapping. false if end of sg 761137d3edbSTejun Heo * list is reached. 762137d3edbSTejun Heo */ 763137d3edbSTejun Heo bool sg_miter_next(struct sg_mapping_iter *miter) 764137d3edbSTejun Heo { 765137d3edbSTejun Heo sg_miter_stop(miter); 766137d3edbSTejun Heo 7674225fc85SImre Deak /* 7684225fc85SImre Deak * Get to the next page if necessary. 7694225fc85SImre Deak * __remaining, __offset is adjusted by sg_miter_stop 7704225fc85SImre Deak */ 77111052004SAkinobu Mita if (!sg_miter_get_next_page(miter)) 77223c560a9STejun Heo return false; 7734225fc85SImre Deak 7742db76d7cSImre Deak miter->page = sg_page_iter_page(&miter->piter); 7754225fc85SImre Deak miter->consumed = miter->length = miter->__remaining; 776137d3edbSTejun Heo 777137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) 7784225fc85SImre Deak miter->addr = kmap_atomic(miter->page) + miter->__offset; 779137d3edbSTejun Heo else 7804225fc85SImre Deak miter->addr = kmap(miter->page) + miter->__offset; 781137d3edbSTejun Heo 782137d3edbSTejun Heo return true; 783137d3edbSTejun Heo } 784137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_next); 785137d3edbSTejun Heo 786137d3edbSTejun Heo /** 787137d3edbSTejun Heo * sg_miter_stop - stop mapping iteration 788137d3edbSTejun Heo * @miter: sg mapping iter to be stopped 789137d3edbSTejun Heo * 790137d3edbSTejun Heo * Description: 791137d3edbSTejun Heo * Stops mapping iterator @miter. @miter should have been started 7924ba6a2b2SMasahiro Yamada * using sg_miter_start(). A stopped iteration can be resumed by 7934ba6a2b2SMasahiro Yamada * calling sg_miter_next() on it. This is useful when resources (kmap) 7944ba6a2b2SMasahiro Yamada * need to be released during iteration. 795137d3edbSTejun Heo * 796137d3edbSTejun Heo * Context: 7978290e2d2STejun Heo * Preemption disabled if the SG_MITER_ATOMIC is set. Don't care 7988290e2d2STejun Heo * otherwise. 799137d3edbSTejun Heo */ 800137d3edbSTejun Heo void sg_miter_stop(struct sg_mapping_iter *miter) 801137d3edbSTejun Heo { 802137d3edbSTejun Heo WARN_ON(miter->consumed > miter->length); 803137d3edbSTejun Heo 804137d3edbSTejun Heo /* drop resources from the last iteration */ 805137d3edbSTejun Heo if (miter->addr) { 806137d3edbSTejun Heo miter->__offset += miter->consumed; 8074225fc85SImre Deak miter->__remaining -= miter->consumed; 808137d3edbSTejun Heo 8093d77b50cSMing Lei if ((miter->__flags & SG_MITER_TO_SG) && 8103d77b50cSMing Lei !PageSlab(miter->page)) 8116de7e356SSebastian Andrzej Siewior flush_kernel_dcache_page(miter->page); 8126de7e356SSebastian Andrzej Siewior 813137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) { 8148290e2d2STejun Heo WARN_ON_ONCE(preemptible()); 815c3eede8eSCong Wang kunmap_atomic(miter->addr); 816137d3edbSTejun Heo } else 817f652c521SArjan van de Ven kunmap(miter->page); 818137d3edbSTejun Heo 819137d3edbSTejun Heo miter->page = NULL; 820137d3edbSTejun Heo miter->addr = NULL; 821137d3edbSTejun Heo miter->length = 0; 822137d3edbSTejun Heo miter->consumed = 0; 823137d3edbSTejun Heo } 824137d3edbSTejun Heo } 825137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_stop); 826137d3edbSTejun Heo 827137d3edbSTejun Heo /** 828b1adaf65SFUJITA Tomonori * sg_copy_buffer - Copy data between a linear buffer and an SG list 829b1adaf65SFUJITA Tomonori * @sgl: The SG list 830b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 831b1adaf65SFUJITA Tomonori * @buf: Where to copy from 832b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 833df642ceaSAkinobu Mita * @skip: Number of bytes to skip before copying 834df642ceaSAkinobu Mita * @to_buffer: transfer direction (true == from an sg list to a 8356e853185SGeert Uytterhoeven * buffer, false == from a buffer to an sg list) 836b1adaf65SFUJITA Tomonori * 837b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 838b1adaf65SFUJITA Tomonori * 839b1adaf65SFUJITA Tomonori **/ 840386ecb12SDave Gordon size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, 841386ecb12SDave Gordon size_t buflen, off_t skip, bool to_buffer) 842b1adaf65SFUJITA Tomonori { 843137d3edbSTejun Heo unsigned int offset = 0; 844137d3edbSTejun Heo struct sg_mapping_iter miter; 8456de7e356SSebastian Andrzej Siewior unsigned int sg_flags = SG_MITER_ATOMIC; 846b1adaf65SFUJITA Tomonori 8476de7e356SSebastian Andrzej Siewior if (to_buffer) 8486de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_FROM_SG; 8496de7e356SSebastian Andrzej Siewior else 8506de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_TO_SG; 8516de7e356SSebastian Andrzej Siewior 8526de7e356SSebastian Andrzej Siewior sg_miter_start(&miter, sgl, nents, sg_flags); 853b1adaf65SFUJITA Tomonori 854df642ceaSAkinobu Mita if (!sg_miter_skip(&miter, skip)) 855df642ceaSAkinobu Mita return false; 856df642ceaSAkinobu Mita 8571d5210efSGilad Ben-Yossef while ((offset < buflen) && sg_miter_next(&miter)) { 858137d3edbSTejun Heo unsigned int len; 859b1adaf65SFUJITA Tomonori 860137d3edbSTejun Heo len = min(miter.length, buflen - offset); 861b1adaf65SFUJITA Tomonori 862b1adaf65SFUJITA Tomonori if (to_buffer) 863137d3edbSTejun Heo memcpy(buf + offset, miter.addr, len); 8646de7e356SSebastian Andrzej Siewior else 865137d3edbSTejun Heo memcpy(miter.addr, buf + offset, len); 866b1adaf65SFUJITA Tomonori 867137d3edbSTejun Heo offset += len; 868b1adaf65SFUJITA Tomonori } 869b1adaf65SFUJITA Tomonori 870137d3edbSTejun Heo sg_miter_stop(&miter); 871b1adaf65SFUJITA Tomonori 872137d3edbSTejun Heo return offset; 873b1adaf65SFUJITA Tomonori } 874386ecb12SDave Gordon EXPORT_SYMBOL(sg_copy_buffer); 875b1adaf65SFUJITA Tomonori 876b1adaf65SFUJITA Tomonori /** 877b1adaf65SFUJITA Tomonori * sg_copy_from_buffer - Copy from a linear buffer to an SG list 878b1adaf65SFUJITA Tomonori * @sgl: The SG list 879b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 880b1adaf65SFUJITA Tomonori * @buf: Where to copy from 881b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 882b1adaf65SFUJITA Tomonori * 883b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 884b1adaf65SFUJITA Tomonori * 885b1adaf65SFUJITA Tomonori **/ 886b1adaf65SFUJITA Tomonori size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, 8872a1bf8f9SDave Gordon const void *buf, size_t buflen) 888b1adaf65SFUJITA Tomonori { 8892a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); 890b1adaf65SFUJITA Tomonori } 891b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_from_buffer); 892b1adaf65SFUJITA Tomonori 893b1adaf65SFUJITA Tomonori /** 894b1adaf65SFUJITA Tomonori * sg_copy_to_buffer - Copy from an SG list to a linear buffer 895b1adaf65SFUJITA Tomonori * @sgl: The SG list 896b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 897b1adaf65SFUJITA Tomonori * @buf: Where to copy to 898b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 899b1adaf65SFUJITA Tomonori * 900b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 901b1adaf65SFUJITA Tomonori * 902b1adaf65SFUJITA Tomonori **/ 903b1adaf65SFUJITA Tomonori size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, 904b1adaf65SFUJITA Tomonori void *buf, size_t buflen) 905b1adaf65SFUJITA Tomonori { 906df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); 907b1adaf65SFUJITA Tomonori } 908b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_to_buffer); 909df642ceaSAkinobu Mita 910df642ceaSAkinobu Mita /** 911df642ceaSAkinobu Mita * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list 912df642ceaSAkinobu Mita * @sgl: The SG list 913df642ceaSAkinobu Mita * @nents: Number of SG entries 914df642ceaSAkinobu Mita * @buf: Where to copy from 915df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 9164dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 917df642ceaSAkinobu Mita * 918df642ceaSAkinobu Mita * Returns the number of copied bytes. 919df642ceaSAkinobu Mita * 920df642ceaSAkinobu Mita **/ 921df642ceaSAkinobu Mita size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, 9222a1bf8f9SDave Gordon const void *buf, size_t buflen, off_t skip) 923df642ceaSAkinobu Mita { 9242a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); 925df642ceaSAkinobu Mita } 926df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_from_buffer); 927df642ceaSAkinobu Mita 928df642ceaSAkinobu Mita /** 929df642ceaSAkinobu Mita * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer 930df642ceaSAkinobu Mita * @sgl: The SG list 931df642ceaSAkinobu Mita * @nents: Number of SG entries 932df642ceaSAkinobu Mita * @buf: Where to copy to 933df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 9344dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 935df642ceaSAkinobu Mita * 936df642ceaSAkinobu Mita * Returns the number of copied bytes. 937df642ceaSAkinobu Mita * 938df642ceaSAkinobu Mita **/ 939df642ceaSAkinobu Mita size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, 940df642ceaSAkinobu Mita void *buf, size_t buflen, off_t skip) 941df642ceaSAkinobu Mita { 942df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); 943df642ceaSAkinobu Mita } 944df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_to_buffer); 9450945e569SJohannes Thumshirn 9460945e569SJohannes Thumshirn /** 9470945e569SJohannes Thumshirn * sg_zero_buffer - Zero-out a part of a SG list 9480945e569SJohannes Thumshirn * @sgl: The SG list 9490945e569SJohannes Thumshirn * @nents: Number of SG entries 9500945e569SJohannes Thumshirn * @buflen: The number of bytes to zero out 9510945e569SJohannes Thumshirn * @skip: Number of bytes to skip before zeroing 9520945e569SJohannes Thumshirn * 9530945e569SJohannes Thumshirn * Returns the number of bytes zeroed. 9540945e569SJohannes Thumshirn **/ 9550945e569SJohannes Thumshirn size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, 9560945e569SJohannes Thumshirn size_t buflen, off_t skip) 9570945e569SJohannes Thumshirn { 9580945e569SJohannes Thumshirn unsigned int offset = 0; 9590945e569SJohannes Thumshirn struct sg_mapping_iter miter; 9600945e569SJohannes Thumshirn unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; 9610945e569SJohannes Thumshirn 9620945e569SJohannes Thumshirn sg_miter_start(&miter, sgl, nents, sg_flags); 9630945e569SJohannes Thumshirn 9640945e569SJohannes Thumshirn if (!sg_miter_skip(&miter, skip)) 9650945e569SJohannes Thumshirn return false; 9660945e569SJohannes Thumshirn 9670945e569SJohannes Thumshirn while (offset < buflen && sg_miter_next(&miter)) { 9680945e569SJohannes Thumshirn unsigned int len; 9690945e569SJohannes Thumshirn 9700945e569SJohannes Thumshirn len = min(miter.length, buflen - offset); 9710945e569SJohannes Thumshirn memset(miter.addr, 0, len); 9720945e569SJohannes Thumshirn 9730945e569SJohannes Thumshirn offset += len; 9740945e569SJohannes Thumshirn } 9750945e569SJohannes Thumshirn 9760945e569SJohannes Thumshirn sg_miter_stop(&miter); 9770945e569SJohannes Thumshirn return offset; 9780945e569SJohannes Thumshirn } 9790945e569SJohannes Thumshirn EXPORT_SYMBOL(sg_zero_buffer); 980