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: 419dbbc3b9SZhen Lei * Allows to know how many entries are in sg, taking into account 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 629dbbc3b9SZhen Lei * the supplied length, taking into account 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 1853e302dbcSMaor Gottlieb * @num_ents: Number of entries in the table 1860db9299fSJens Axboe * 1870db9299fSJens Axboe * Description: 1887cedb1f1SJames Bottomley * Free an sg table previously allocated and setup with 1897cedb1f1SJames Bottomley * __sg_alloc_table(). The @max_ents value must be identical to 1907cedb1f1SJames Bottomley * that previously used with __sg_alloc_table(). 1910db9299fSJens Axboe * 1920db9299fSJens Axboe **/ 1937cedb1f1SJames Bottomley void __sg_free_table(struct sg_table *table, unsigned int max_ents, 1943e302dbcSMaor Gottlieb unsigned int nents_first_chunk, sg_free_fn *free_fn, 1953e302dbcSMaor Gottlieb unsigned int num_ents) 1960db9299fSJens Axboe { 1970db9299fSJens Axboe struct scatterlist *sgl, *next; 1984635873cSMing Lei unsigned curr_max_ents = nents_first_chunk ?: max_ents; 1990db9299fSJens Axboe 2000db9299fSJens Axboe if (unlikely(!table->sgl)) 2010db9299fSJens Axboe return; 2020db9299fSJens Axboe 2030db9299fSJens Axboe sgl = table->sgl; 2043e302dbcSMaor Gottlieb while (num_ents) { 2053e302dbcSMaor Gottlieb unsigned int alloc_size = num_ents; 2060db9299fSJens Axboe unsigned int sg_size; 2070db9299fSJens Axboe 2080db9299fSJens Axboe /* 2097cedb1f1SJames Bottomley * If we have more than max_ents segments left, 2100db9299fSJens Axboe * then assign 'next' to the sg table after the current one. 2110db9299fSJens Axboe * sg_size is then one less than alloc size, since the last 2120db9299fSJens Axboe * element is the chain pointer. 2130db9299fSJens Axboe */ 2144635873cSMing Lei if (alloc_size > curr_max_ents) { 2154635873cSMing Lei next = sg_chain_ptr(&sgl[curr_max_ents - 1]); 2164635873cSMing Lei alloc_size = curr_max_ents; 2170db9299fSJens Axboe sg_size = alloc_size - 1; 2180db9299fSJens Axboe } else { 2190db9299fSJens Axboe sg_size = alloc_size; 2200db9299fSJens Axboe next = NULL; 2210db9299fSJens Axboe } 2220db9299fSJens Axboe 2233e302dbcSMaor Gottlieb num_ents -= sg_size; 2244635873cSMing Lei if (nents_first_chunk) 2254635873cSMing Lei nents_first_chunk = 0; 226c21e59d8STony Battersby else 227c21e59d8STony Battersby free_fn(sgl, alloc_size); 2280db9299fSJens Axboe sgl = next; 2294635873cSMing Lei curr_max_ents = max_ents; 2300db9299fSJens Axboe } 2310db9299fSJens Axboe 2320db9299fSJens Axboe table->sgl = NULL; 2330db9299fSJens Axboe } 2340db9299fSJens Axboe EXPORT_SYMBOL(__sg_free_table); 2350db9299fSJens Axboe 2360db9299fSJens Axboe /** 2373e302dbcSMaor Gottlieb * sg_free_append_table - Free a previously allocated append sg table. 2383e302dbcSMaor Gottlieb * @table: The mapped sg append table header 2393e302dbcSMaor Gottlieb * 2403e302dbcSMaor Gottlieb **/ 2413e302dbcSMaor Gottlieb void sg_free_append_table(struct sg_append_table *table) 2423e302dbcSMaor Gottlieb { 2433e302dbcSMaor Gottlieb __sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, false, sg_kfree, 2443e302dbcSMaor Gottlieb table->total_nents); 2453e302dbcSMaor Gottlieb } 2463e302dbcSMaor Gottlieb EXPORT_SYMBOL(sg_free_append_table); 2473e302dbcSMaor Gottlieb 2483e302dbcSMaor Gottlieb 2493e302dbcSMaor Gottlieb /** 2500db9299fSJens Axboe * sg_free_table - Free a previously allocated sg table 2510db9299fSJens Axboe * @table: The mapped sg table header 2520db9299fSJens Axboe * 2530db9299fSJens Axboe **/ 2540db9299fSJens Axboe void sg_free_table(struct sg_table *table) 2550db9299fSJens Axboe { 2563e302dbcSMaor Gottlieb __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree, 2573e302dbcSMaor Gottlieb table->orig_nents); 2580db9299fSJens Axboe } 2590db9299fSJens Axboe EXPORT_SYMBOL(sg_free_table); 2600db9299fSJens Axboe 2610db9299fSJens Axboe /** 2620db9299fSJens Axboe * __sg_alloc_table - Allocate and initialize an sg table with given allocator 2630db9299fSJens Axboe * @table: The sg table header to use 2640db9299fSJens Axboe * @nents: Number of entries in sg list 2657cedb1f1SJames Bottomley * @max_ents: The maximum number of entries the allocator returns per call 2664635873cSMing Lei * @nents_first_chunk: Number of entries int the (preallocated) first 2674635873cSMing Lei * scatterlist chunk, 0 means no such preallocated chunk provided by user 2680db9299fSJens Axboe * @gfp_mask: GFP allocation mask 2690db9299fSJens Axboe * @alloc_fn: Allocator to use 2700db9299fSJens Axboe * 2717cedb1f1SJames Bottomley * Description: 2727cedb1f1SJames Bottomley * This function returns a @table @nents long. The allocator is 2737cedb1f1SJames Bottomley * defined to return scatterlist chunks of maximum size @max_ents. 2747cedb1f1SJames Bottomley * Thus if @nents is bigger than @max_ents, the scatterlists will be 2757cedb1f1SJames Bottomley * chained in units of @max_ents. 2767cedb1f1SJames Bottomley * 2770db9299fSJens Axboe * Notes: 2780db9299fSJens Axboe * If this function returns non-0 (eg failure), the caller must call 2790db9299fSJens Axboe * __sg_free_table() to cleanup any leftover allocations. 2800db9299fSJens Axboe * 2810db9299fSJens Axboe **/ 2827cedb1f1SJames Bottomley int __sg_alloc_table(struct sg_table *table, unsigned int nents, 283c53c6d6aSChristoph Hellwig unsigned int max_ents, struct scatterlist *first_chunk, 2844635873cSMing Lei unsigned int nents_first_chunk, gfp_t gfp_mask, 2854635873cSMing Lei sg_alloc_fn *alloc_fn) 2860db9299fSJens Axboe { 2870db9299fSJens Axboe struct scatterlist *sg, *prv; 2880db9299fSJens Axboe unsigned int left; 2894635873cSMing Lei unsigned curr_max_ents = nents_first_chunk ?: max_ents; 2904635873cSMing Lei unsigned prv_max_ents; 2910db9299fSJens Axboe 29227daabd9SDan Carpenter memset(table, 0, sizeof(*table)); 29327daabd9SDan Carpenter 29427daabd9SDan Carpenter if (nents == 0) 29527daabd9SDan Carpenter return -EINVAL; 2967c703e54SChristoph Hellwig #ifdef CONFIG_ARCH_NO_SG_CHAIN 2976fd59a83SNick Bowler if (WARN_ON_ONCE(nents > max_ents)) 2986fd59a83SNick Bowler return -EINVAL; 2990db9299fSJens Axboe #endif 3000db9299fSJens Axboe 3010db9299fSJens Axboe left = nents; 3020db9299fSJens Axboe prv = NULL; 3030db9299fSJens Axboe do { 3040db9299fSJens Axboe unsigned int sg_size, alloc_size = left; 3050db9299fSJens Axboe 3064635873cSMing Lei if (alloc_size > curr_max_ents) { 3074635873cSMing Lei alloc_size = curr_max_ents; 3080db9299fSJens Axboe sg_size = alloc_size - 1; 3090db9299fSJens Axboe } else 3100db9299fSJens Axboe sg_size = alloc_size; 3110db9299fSJens Axboe 3120db9299fSJens Axboe left -= sg_size; 3130db9299fSJens Axboe 314c53c6d6aSChristoph Hellwig if (first_chunk) { 315c53c6d6aSChristoph Hellwig sg = first_chunk; 316c53c6d6aSChristoph Hellwig first_chunk = NULL; 317c53c6d6aSChristoph Hellwig } else { 3180db9299fSJens Axboe sg = alloc_fn(alloc_size, gfp_mask); 319c53c6d6aSChristoph Hellwig } 320edce6820SJeffrey Carlyle if (unlikely(!sg)) { 321edce6820SJeffrey Carlyle /* 322edce6820SJeffrey Carlyle * Adjust entry count to reflect that the last 323edce6820SJeffrey Carlyle * entry of the previous table won't be used for 324edce6820SJeffrey Carlyle * linkage. Without this, sg_kfree() may get 325edce6820SJeffrey Carlyle * confused. 326edce6820SJeffrey Carlyle */ 327edce6820SJeffrey Carlyle if (prv) 328edce6820SJeffrey Carlyle table->nents = ++table->orig_nents; 329edce6820SJeffrey Carlyle 3300db9299fSJens Axboe return -ENOMEM; 331edce6820SJeffrey Carlyle } 3320db9299fSJens Axboe 3330db9299fSJens Axboe sg_init_table(sg, alloc_size); 3340db9299fSJens Axboe table->nents = table->orig_nents += sg_size; 3350db9299fSJens Axboe 3360db9299fSJens Axboe /* 3370db9299fSJens Axboe * If this is the first mapping, assign the sg table header. 3380db9299fSJens Axboe * If this is not the first mapping, chain previous part. 3390db9299fSJens Axboe */ 3400db9299fSJens Axboe if (prv) 3414635873cSMing Lei sg_chain(prv, prv_max_ents, sg); 3420db9299fSJens Axboe else 3430db9299fSJens Axboe table->sgl = sg; 3440db9299fSJens Axboe 3450db9299fSJens Axboe /* 3460db9299fSJens Axboe * If no more entries after this one, mark the end 3470db9299fSJens Axboe */ 3480db9299fSJens Axboe if (!left) 3490db9299fSJens Axboe sg_mark_end(&sg[sg_size - 1]); 3500db9299fSJens Axboe 3510db9299fSJens Axboe prv = sg; 3524635873cSMing Lei prv_max_ents = curr_max_ents; 3534635873cSMing Lei curr_max_ents = max_ents; 3540db9299fSJens Axboe } while (left); 3550db9299fSJens Axboe 3560db9299fSJens Axboe return 0; 3570db9299fSJens Axboe } 3580db9299fSJens Axboe EXPORT_SYMBOL(__sg_alloc_table); 3590db9299fSJens Axboe 3600db9299fSJens Axboe /** 3610db9299fSJens Axboe * sg_alloc_table - Allocate and initialize an sg table 3620db9299fSJens Axboe * @table: The sg table header to use 3630db9299fSJens Axboe * @nents: Number of entries in sg list 3640db9299fSJens Axboe * @gfp_mask: GFP allocation mask 3650db9299fSJens Axboe * 3660db9299fSJens Axboe * Description: 3670db9299fSJens Axboe * Allocate and initialize an sg table. If @nents@ is larger than 3680db9299fSJens Axboe * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. 3690db9299fSJens Axboe * 3700db9299fSJens Axboe **/ 3710db9299fSJens Axboe int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) 3720db9299fSJens Axboe { 3730db9299fSJens Axboe int ret; 3740db9299fSJens Axboe 3757cedb1f1SJames Bottomley ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, 3764635873cSMing Lei NULL, 0, gfp_mask, sg_kmalloc); 3770db9299fSJens Axboe if (unlikely(ret)) 3783e302dbcSMaor Gottlieb sg_free_table(table); 3790db9299fSJens Axboe return ret; 3800db9299fSJens Axboe } 3810db9299fSJens Axboe EXPORT_SYMBOL(sg_alloc_table); 382b1adaf65SFUJITA Tomonori 3833e302dbcSMaor Gottlieb static struct scatterlist *get_next_sg(struct sg_append_table *table, 38407da1223SMaor Gottlieb struct scatterlist *cur, 38507da1223SMaor Gottlieb unsigned long needed_sges, 38607da1223SMaor Gottlieb gfp_t gfp_mask) 38707da1223SMaor Gottlieb { 38807da1223SMaor Gottlieb struct scatterlist *new_sg, *next_sg; 38907da1223SMaor Gottlieb unsigned int alloc_size; 39007da1223SMaor Gottlieb 39107da1223SMaor Gottlieb if (cur) { 39207da1223SMaor Gottlieb next_sg = sg_next(cur); 39307da1223SMaor Gottlieb /* Check if last entry should be keeped for chainning */ 39407da1223SMaor Gottlieb if (!sg_is_last(next_sg) || needed_sges == 1) 39507da1223SMaor Gottlieb return next_sg; 39607da1223SMaor Gottlieb } 39707da1223SMaor Gottlieb 39807da1223SMaor Gottlieb alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); 39907da1223SMaor Gottlieb new_sg = sg_kmalloc(alloc_size, gfp_mask); 40007da1223SMaor Gottlieb if (!new_sg) 40107da1223SMaor Gottlieb return ERR_PTR(-ENOMEM); 40207da1223SMaor Gottlieb sg_init_table(new_sg, alloc_size); 40307da1223SMaor Gottlieb if (cur) { 4043e302dbcSMaor Gottlieb table->total_nents += alloc_size - 1; 40507da1223SMaor Gottlieb __sg_chain(next_sg, new_sg); 40607da1223SMaor Gottlieb } else { 4073e302dbcSMaor Gottlieb table->sgt.sgl = new_sg; 4083e302dbcSMaor Gottlieb table->total_nents = alloc_size; 40907da1223SMaor Gottlieb } 41007da1223SMaor Gottlieb return new_sg; 41107da1223SMaor Gottlieb } 41207da1223SMaor Gottlieb 413b1adaf65SFUJITA Tomonori /** 4143e302dbcSMaor Gottlieb * sg_alloc_append_table_from_pages - Allocate and initialize an append sg 4153e302dbcSMaor Gottlieb * table from an array of pages 4163e302dbcSMaor Gottlieb * @sgt_append: The sg append table to use 417efc42bc9STomasz Stanislawski * @pages: Pointer to an array of page pointers 418efc42bc9STomasz Stanislawski * @n_pages: Number of pages in the pages array 419efc42bc9STomasz Stanislawski * @offset: Offset from start of the first page to the start of a buffer 420efc42bc9STomasz Stanislawski * @size: Number of valid bytes in the buffer (after offset) 4219a40401cSJason Gunthorpe * @max_segment: Maximum size of a scatterlist element in bytes 42207da1223SMaor Gottlieb * @left_pages: Left pages caller have to set after this call 423efc42bc9STomasz Stanislawski * @gfp_mask: GFP allocation mask 424efc42bc9STomasz Stanislawski * 425efc42bc9STomasz Stanislawski * Description: 4263e302dbcSMaor Gottlieb * In the first call it allocate and initialize an sg table from a list of 4273e302dbcSMaor Gottlieb * pages, else reuse the scatterlist from sgt_append. Contiguous ranges of 4283e302dbcSMaor Gottlieb * the pages are squashed into a single scatterlist entry up to the maximum 4293e302dbcSMaor Gottlieb * size specified in @max_segment. A user may provide an offset at a start 4303e302dbcSMaor Gottlieb * and a size of valid data in a buffer specified by the page array. The 4313e302dbcSMaor Gottlieb * returned sg table is released by sg_free_append_table 432efc42bc9STomasz Stanislawski * 433efc42bc9STomasz Stanislawski * Returns: 4343e302dbcSMaor Gottlieb * 0 on success, negative error on failure 43507da1223SMaor Gottlieb * 43607da1223SMaor Gottlieb * Notes: 43707da1223SMaor Gottlieb * If this function returns non-0 (eg failure), the caller must call 4383e302dbcSMaor Gottlieb * sg_free_append_table() to cleanup any leftover allocations. 4393e302dbcSMaor Gottlieb * 4403e302dbcSMaor Gottlieb * In the fist call, sgt_append must by initialized. 441efc42bc9STomasz Stanislawski */ 4423e302dbcSMaor Gottlieb int sg_alloc_append_table_from_pages(struct sg_append_table *sgt_append, 44307da1223SMaor Gottlieb struct page **pages, unsigned int n_pages, unsigned int offset, 44489d8589cSTvrtko Ursulin unsigned long size, unsigned int max_segment, 4453e302dbcSMaor Gottlieb unsigned int left_pages, gfp_t gfp_mask) 446efc42bc9STomasz Stanislawski { 44707da1223SMaor Gottlieb unsigned int chunks, cur_page, seg_len, i, prv_len = 0; 44807da1223SMaor Gottlieb unsigned int added_nents = 0; 4493e302dbcSMaor Gottlieb struct scatterlist *s = sgt_append->prv; 450efc42bc9STomasz Stanislawski 4519a40401cSJason Gunthorpe /* 4529a40401cSJason Gunthorpe * The algorithm below requires max_segment to be aligned to PAGE_SIZE 4539a40401cSJason Gunthorpe * otherwise it can overshoot. 4549a40401cSJason Gunthorpe */ 4559a40401cSJason Gunthorpe max_segment = ALIGN_DOWN(max_segment, PAGE_SIZE); 4569a40401cSJason Gunthorpe if (WARN_ON(max_segment < PAGE_SIZE)) 4573e302dbcSMaor Gottlieb return -EINVAL; 45807da1223SMaor Gottlieb 4593e302dbcSMaor Gottlieb if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && sgt_append->prv) 4603e302dbcSMaor Gottlieb return -EOPNOTSUPP; 46107da1223SMaor Gottlieb 4623e302dbcSMaor Gottlieb if (sgt_append->prv) { 4633e302dbcSMaor Gottlieb unsigned long paddr = 4643e302dbcSMaor Gottlieb (page_to_pfn(sg_page(sgt_append->prv)) * PAGE_SIZE + 4653e302dbcSMaor Gottlieb sgt_append->prv->offset + sgt_append->prv->length) / 46607da1223SMaor Gottlieb PAGE_SIZE; 46707da1223SMaor Gottlieb 46807da1223SMaor Gottlieb if (WARN_ON(offset)) 4693e302dbcSMaor Gottlieb return -EINVAL; 47007da1223SMaor Gottlieb 47107da1223SMaor Gottlieb /* Merge contiguous pages into the last SG */ 4723e302dbcSMaor Gottlieb prv_len = sgt_append->prv->length; 47307da1223SMaor Gottlieb while (n_pages && page_to_pfn(pages[0]) == paddr) { 4743e302dbcSMaor Gottlieb if (sgt_append->prv->length + PAGE_SIZE > max_segment) 47507da1223SMaor Gottlieb break; 4763e302dbcSMaor Gottlieb sgt_append->prv->length += PAGE_SIZE; 47707da1223SMaor Gottlieb paddr++; 47807da1223SMaor Gottlieb pages++; 47907da1223SMaor Gottlieb n_pages--; 48007da1223SMaor Gottlieb } 48107da1223SMaor Gottlieb if (!n_pages) 48207da1223SMaor Gottlieb goto out; 48307da1223SMaor Gottlieb } 48489d8589cSTvrtko Ursulin 485efc42bc9STomasz Stanislawski /* compute number of contiguous chunks */ 486efc42bc9STomasz Stanislawski chunks = 1; 487c125906bSTvrtko Ursulin seg_len = 0; 488c125906bSTvrtko Ursulin for (i = 1; i < n_pages; i++) { 489c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 490c125906bSTvrtko Ursulin if (seg_len >= max_segment || 491c125906bSTvrtko Ursulin page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { 492c125906bSTvrtko Ursulin chunks++; 493c125906bSTvrtko Ursulin seg_len = 0; 494c125906bSTvrtko Ursulin } 495c125906bSTvrtko Ursulin } 496efc42bc9STomasz Stanislawski 497efc42bc9STomasz Stanislawski /* merging chunks and putting them into the scatterlist */ 498efc42bc9STomasz Stanislawski cur_page = 0; 49907da1223SMaor Gottlieb for (i = 0; i < chunks; i++) { 500c125906bSTvrtko Ursulin unsigned int j, chunk_size; 501efc42bc9STomasz Stanislawski 502efc42bc9STomasz Stanislawski /* look for the end of the current chunk */ 503c125906bSTvrtko Ursulin seg_len = 0; 504c125906bSTvrtko Ursulin for (j = cur_page + 1; j < n_pages; j++) { 505c125906bSTvrtko Ursulin seg_len += PAGE_SIZE; 506c125906bSTvrtko Ursulin if (seg_len >= max_segment || 507c125906bSTvrtko Ursulin page_to_pfn(pages[j]) != 508efc42bc9STomasz Stanislawski page_to_pfn(pages[j - 1]) + 1) 509efc42bc9STomasz Stanislawski break; 510c125906bSTvrtko Ursulin } 511efc42bc9STomasz Stanislawski 51207da1223SMaor Gottlieb /* Pass how many chunks might be left */ 5133e302dbcSMaor Gottlieb s = get_next_sg(sgt_append, s, chunks - i + left_pages, 5143e302dbcSMaor Gottlieb gfp_mask); 51507da1223SMaor Gottlieb if (IS_ERR(s)) { 51607da1223SMaor Gottlieb /* 51707da1223SMaor Gottlieb * Adjust entry length to be as before function was 51807da1223SMaor Gottlieb * called. 51907da1223SMaor Gottlieb */ 5203e302dbcSMaor Gottlieb if (sgt_append->prv) 5213e302dbcSMaor Gottlieb sgt_append->prv->length = prv_len; 5223e302dbcSMaor Gottlieb return PTR_ERR(s); 52307da1223SMaor Gottlieb } 524efc42bc9STomasz Stanislawski chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; 525c125906bSTvrtko Ursulin sg_set_page(s, pages[cur_page], 526c125906bSTvrtko Ursulin min_t(unsigned long, size, chunk_size), offset); 52707da1223SMaor Gottlieb added_nents++; 528efc42bc9STomasz Stanislawski size -= chunk_size; 529efc42bc9STomasz Stanislawski offset = 0; 530efc42bc9STomasz Stanislawski cur_page = j; 531efc42bc9STomasz Stanislawski } 5323e302dbcSMaor Gottlieb sgt_append->sgt.nents += added_nents; 5333e302dbcSMaor Gottlieb sgt_append->sgt.orig_nents = sgt_append->sgt.nents; 5343e302dbcSMaor Gottlieb sgt_append->prv = s; 53507da1223SMaor Gottlieb out: 53607da1223SMaor Gottlieb if (!left_pages) 53707da1223SMaor Gottlieb sg_mark_end(s); 5383e302dbcSMaor Gottlieb return 0; 539efc42bc9STomasz Stanislawski } 54090e7a6deSMaor Gottlieb EXPORT_SYMBOL(sg_alloc_append_table_from_pages); 54189d8589cSTvrtko Ursulin 54289d8589cSTvrtko Ursulin /** 54390e7a6deSMaor Gottlieb * sg_alloc_table_from_pages_segment - Allocate and initialize an sg table from 54490e7a6deSMaor Gottlieb * an array of pages and given maximum 54590e7a6deSMaor Gottlieb * segment. 54689d8589cSTvrtko Ursulin * @sgt: The sg table header to use 54789d8589cSTvrtko Ursulin * @pages: Pointer to an array of page pointers 54889d8589cSTvrtko Ursulin * @n_pages: Number of pages in the pages array 54989d8589cSTvrtko Ursulin * @offset: Offset from start of the first page to the start of a buffer 55089d8589cSTvrtko Ursulin * @size: Number of valid bytes in the buffer (after offset) 55190e7a6deSMaor Gottlieb * @max_segment: Maximum size of a scatterlist element in bytes 55289d8589cSTvrtko Ursulin * @gfp_mask: GFP allocation mask 55389d8589cSTvrtko Ursulin * 55489d8589cSTvrtko Ursulin * Description: 55589d8589cSTvrtko Ursulin * Allocate and initialize an sg table from a list of pages. Contiguous 55690e7a6deSMaor Gottlieb * ranges of the pages are squashed into a single scatterlist node up to the 55790e7a6deSMaor Gottlieb * maximum size specified in @max_segment. A user may provide an offset at a 55890e7a6deSMaor Gottlieb * start and a size of valid data in a buffer specified by the page array. 55990e7a6deSMaor Gottlieb * 56090e7a6deSMaor Gottlieb * The returned sg table is released by sg_free_table. 56189d8589cSTvrtko Ursulin * 56289d8589cSTvrtko Ursulin * Returns: 56389d8589cSTvrtko Ursulin * 0 on success, negative error on failure 56489d8589cSTvrtko Ursulin */ 56590e7a6deSMaor Gottlieb int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages, 56689d8589cSTvrtko Ursulin unsigned int n_pages, unsigned int offset, 56790e7a6deSMaor Gottlieb unsigned long size, unsigned int max_segment, 56890e7a6deSMaor Gottlieb gfp_t gfp_mask) 56989d8589cSTvrtko Ursulin { 5703e302dbcSMaor Gottlieb struct sg_append_table append = {}; 5713e302dbcSMaor Gottlieb int err; 5723e302dbcSMaor Gottlieb 5733e302dbcSMaor Gottlieb err = sg_alloc_append_table_from_pages(&append, pages, n_pages, offset, 5743e302dbcSMaor Gottlieb size, max_segment, 0, gfp_mask); 5753e302dbcSMaor Gottlieb if (err) { 5763e302dbcSMaor Gottlieb sg_free_append_table(&append); 5773e302dbcSMaor Gottlieb return err; 5783e302dbcSMaor Gottlieb } 5793e302dbcSMaor Gottlieb memcpy(sgt, &append.sgt, sizeof(*sgt)); 5803e302dbcSMaor Gottlieb WARN_ON(append.total_nents != sgt->orig_nents); 5813e302dbcSMaor Gottlieb return 0; 58289d8589cSTvrtko Ursulin } 58390e7a6deSMaor Gottlieb EXPORT_SYMBOL(sg_alloc_table_from_pages_segment); 584efc42bc9STomasz Stanislawski 585e80a0af4SBart Van Assche #ifdef CONFIG_SGL_ALLOC 586e80a0af4SBart Van Assche 587e80a0af4SBart Van Assche /** 588e80a0af4SBart Van Assche * sgl_alloc_order - allocate a scatterlist and its pages 589e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist. Must be at least one 590e80a0af4SBart Van Assche * @order: Second argument for alloc_pages() 591e80a0af4SBart Van Assche * @chainable: Whether or not to allocate an extra element in the scatterlist 592e80a0af4SBart Van Assche * for scatterlist chaining purposes 593e80a0af4SBart Van Assche * @gfp: Memory allocation flags 594e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist that have pages 595e80a0af4SBart Van Assche * 596e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 597e80a0af4SBart Van Assche */ 598e80a0af4SBart Van Assche struct scatterlist *sgl_alloc_order(unsigned long long length, 599e80a0af4SBart Van Assche unsigned int order, bool chainable, 600e80a0af4SBart Van Assche gfp_t gfp, unsigned int *nent_p) 601e80a0af4SBart Van Assche { 602e80a0af4SBart Van Assche struct scatterlist *sgl, *sg; 603e80a0af4SBart Van Assche struct page *page; 604e80a0af4SBart Van Assche unsigned int nent, nalloc; 605e80a0af4SBart Van Assche u32 elem_len; 606e80a0af4SBart Van Assche 607e80a0af4SBart Van Assche nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); 608e80a0af4SBart Van Assche /* Check for integer overflow */ 609e80a0af4SBart Van Assche if (length > (nent << (PAGE_SHIFT + order))) 610e80a0af4SBart Van Assche return NULL; 611e80a0af4SBart Van Assche nalloc = nent; 612e80a0af4SBart Van Assche if (chainable) { 613e80a0af4SBart Van Assche /* Check for integer overflow */ 614e80a0af4SBart Van Assche if (nalloc + 1 < nalloc) 615e80a0af4SBart Van Assche return NULL; 616e80a0af4SBart Van Assche nalloc++; 617e80a0af4SBart Van Assche } 618e80a0af4SBart Van Assche sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), 6196ed9b92eSChristophe JAILLET gfp & ~GFP_DMA); 620e80a0af4SBart Van Assche if (!sgl) 621e80a0af4SBart Van Assche return NULL; 622e80a0af4SBart Van Assche 6238c7a8d1cSBart Van Assche sg_init_table(sgl, nalloc); 624e80a0af4SBart Van Assche sg = sgl; 625e80a0af4SBart Van Assche while (length) { 626e80a0af4SBart Van Assche elem_len = min_t(u64, length, PAGE_SIZE << order); 627e80a0af4SBart Van Assche page = alloc_pages(gfp, order); 628e80a0af4SBart Van Assche if (!page) { 629b2a182a4SDouglas Gilbert sgl_free_order(sgl, order); 630e80a0af4SBart Van Assche return NULL; 631e80a0af4SBart Van Assche } 632e80a0af4SBart Van Assche 633e80a0af4SBart Van Assche sg_set_page(sg, page, elem_len, 0); 634e80a0af4SBart Van Assche length -= elem_len; 635e80a0af4SBart Van Assche sg = sg_next(sg); 636e80a0af4SBart Van Assche } 6378c7a8d1cSBart Van Assche WARN_ONCE(length, "length = %lld\n", length); 638e80a0af4SBart Van Assche if (nent_p) 639e80a0af4SBart Van Assche *nent_p = nent; 640e80a0af4SBart Van Assche return sgl; 641e80a0af4SBart Van Assche } 642e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc_order); 643e80a0af4SBart Van Assche 644e80a0af4SBart Van Assche /** 645e80a0af4SBart Van Assche * sgl_alloc - allocate a scatterlist and its pages 646e80a0af4SBart Van Assche * @length: Length in bytes of the scatterlist 647e80a0af4SBart Van Assche * @gfp: Memory allocation flags 648e80a0af4SBart Van Assche * @nent_p: [out] Number of entries in the scatterlist 649e80a0af4SBart Van Assche * 650e80a0af4SBart Van Assche * Returns: A pointer to an initialized scatterlist or %NULL upon failure. 651e80a0af4SBart Van Assche */ 652e80a0af4SBart Van Assche struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, 653e80a0af4SBart Van Assche unsigned int *nent_p) 654e80a0af4SBart Van Assche { 655e80a0af4SBart Van Assche return sgl_alloc_order(length, 0, false, gfp, nent_p); 656e80a0af4SBart Van Assche } 657e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_alloc); 658e80a0af4SBart Van Assche 659e80a0af4SBart Van Assche /** 6608c7a8d1cSBart Van Assche * sgl_free_n_order - free a scatterlist and its pages 6618c7a8d1cSBart Van Assche * @sgl: Scatterlist with one or more elements 6628c7a8d1cSBart Van Assche * @nents: Maximum number of elements to free 6638c7a8d1cSBart Van Assche * @order: Second argument for __free_pages() 6648c7a8d1cSBart Van Assche * 6658c7a8d1cSBart Van Assche * Notes: 6668c7a8d1cSBart Van Assche * - If several scatterlists have been chained and each chain element is 6678c7a8d1cSBart Van Assche * freed separately then it's essential to set nents correctly to avoid that a 6688c7a8d1cSBart Van Assche * page would get freed twice. 6698c7a8d1cSBart Van Assche * - All pages in a chained scatterlist can be freed at once by setting @nents 6708c7a8d1cSBart Van Assche * to a high number. 6718c7a8d1cSBart Van Assche */ 6728c7a8d1cSBart Van Assche void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) 6738c7a8d1cSBart Van Assche { 6748c7a8d1cSBart Van Assche struct scatterlist *sg; 6758c7a8d1cSBart Van Assche struct page *page; 6768c7a8d1cSBart Van Assche int i; 6778c7a8d1cSBart Van Assche 6788c7a8d1cSBart Van Assche for_each_sg(sgl, sg, nents, i) { 6798c7a8d1cSBart Van Assche if (!sg) 6808c7a8d1cSBart Van Assche break; 6818c7a8d1cSBart Van Assche page = sg_page(sg); 6828c7a8d1cSBart Van Assche if (page) 6838c7a8d1cSBart Van Assche __free_pages(page, order); 6848c7a8d1cSBart Van Assche } 6858c7a8d1cSBart Van Assche kfree(sgl); 6868c7a8d1cSBart Van Assche } 6878c7a8d1cSBart Van Assche EXPORT_SYMBOL(sgl_free_n_order); 6888c7a8d1cSBart Van Assche 6898c7a8d1cSBart Van Assche /** 690e80a0af4SBart Van Assche * sgl_free_order - free a scatterlist and its pages 691e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 692e80a0af4SBart Van Assche * @order: Second argument for __free_pages() 693e80a0af4SBart Van Assche */ 694e80a0af4SBart Van Assche void sgl_free_order(struct scatterlist *sgl, int order) 695e80a0af4SBart Van Assche { 6968c7a8d1cSBart Van Assche sgl_free_n_order(sgl, INT_MAX, order); 697e80a0af4SBart Van Assche } 698e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free_order); 699e80a0af4SBart Van Assche 700e80a0af4SBart Van Assche /** 701e80a0af4SBart Van Assche * sgl_free - free a scatterlist and its pages 702e80a0af4SBart Van Assche * @sgl: Scatterlist with one or more elements 703e80a0af4SBart Van Assche */ 704e80a0af4SBart Van Assche void sgl_free(struct scatterlist *sgl) 705e80a0af4SBart Van Assche { 706e80a0af4SBart Van Assche sgl_free_order(sgl, 0); 707e80a0af4SBart Van Assche } 708e80a0af4SBart Van Assche EXPORT_SYMBOL(sgl_free); 709e80a0af4SBart Van Assche 710e80a0af4SBart Van Assche #endif /* CONFIG_SGL_ALLOC */ 711e80a0af4SBart Van Assche 712a321e91bSImre Deak void __sg_page_iter_start(struct sg_page_iter *piter, 713a321e91bSImre Deak struct scatterlist *sglist, unsigned int nents, 714a321e91bSImre Deak unsigned long pgoffset) 715a321e91bSImre Deak { 716a321e91bSImre Deak piter->__pg_advance = 0; 717a321e91bSImre Deak piter->__nents = nents; 718a321e91bSImre Deak 719a321e91bSImre Deak piter->sg = sglist; 720a321e91bSImre Deak piter->sg_pgoffset = pgoffset; 721a321e91bSImre Deak } 722a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_start); 723a321e91bSImre Deak 724a321e91bSImre Deak static int sg_page_count(struct scatterlist *sg) 725a321e91bSImre Deak { 726a321e91bSImre Deak return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; 727a321e91bSImre Deak } 728a321e91bSImre Deak 729a321e91bSImre Deak bool __sg_page_iter_next(struct sg_page_iter *piter) 730a321e91bSImre Deak { 731a321e91bSImre Deak if (!piter->__nents || !piter->sg) 732a321e91bSImre Deak return false; 733a321e91bSImre Deak 734a321e91bSImre Deak piter->sg_pgoffset += piter->__pg_advance; 735a321e91bSImre Deak piter->__pg_advance = 1; 736a321e91bSImre Deak 737a321e91bSImre Deak while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { 738a321e91bSImre Deak piter->sg_pgoffset -= sg_page_count(piter->sg); 739a321e91bSImre Deak piter->sg = sg_next(piter->sg); 740a321e91bSImre Deak if (!--piter->__nents || !piter->sg) 741a321e91bSImre Deak return false; 742a321e91bSImre Deak } 743a321e91bSImre Deak 744a321e91bSImre Deak return true; 745a321e91bSImre Deak } 746a321e91bSImre Deak EXPORT_SYMBOL(__sg_page_iter_next); 747a321e91bSImre Deak 748d901b276SJason Gunthorpe static int sg_dma_page_count(struct scatterlist *sg) 749d901b276SJason Gunthorpe { 750d901b276SJason Gunthorpe return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; 751d901b276SJason Gunthorpe } 752d901b276SJason Gunthorpe 753d901b276SJason Gunthorpe bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) 754d901b276SJason Gunthorpe { 755d901b276SJason Gunthorpe struct sg_page_iter *piter = &dma_iter->base; 756d901b276SJason Gunthorpe 757d901b276SJason Gunthorpe if (!piter->__nents || !piter->sg) 758d901b276SJason Gunthorpe return false; 759d901b276SJason Gunthorpe 760d901b276SJason Gunthorpe piter->sg_pgoffset += piter->__pg_advance; 761d901b276SJason Gunthorpe piter->__pg_advance = 1; 762d901b276SJason Gunthorpe 763d901b276SJason Gunthorpe while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { 764d901b276SJason Gunthorpe piter->sg_pgoffset -= sg_dma_page_count(piter->sg); 765d901b276SJason Gunthorpe piter->sg = sg_next(piter->sg); 766d901b276SJason Gunthorpe if (!--piter->__nents || !piter->sg) 767d901b276SJason Gunthorpe return false; 768d901b276SJason Gunthorpe } 769d901b276SJason Gunthorpe 770d901b276SJason Gunthorpe return true; 771d901b276SJason Gunthorpe } 772d901b276SJason Gunthorpe EXPORT_SYMBOL(__sg_page_iter_dma_next); 773d901b276SJason Gunthorpe 774efc42bc9STomasz Stanislawski /** 775137d3edbSTejun Heo * sg_miter_start - start mapping iteration over a sg list 776137d3edbSTejun Heo * @miter: sg mapping iter to be started 777137d3edbSTejun Heo * @sgl: sg list to iterate over 778137d3edbSTejun Heo * @nents: number of sg entries 779137d3edbSTejun Heo * 780137d3edbSTejun Heo * Description: 781137d3edbSTejun Heo * Starts mapping iterator @miter. 782137d3edbSTejun Heo * 783137d3edbSTejun Heo * Context: 784137d3edbSTejun Heo * Don't care. 785137d3edbSTejun Heo */ 786137d3edbSTejun Heo void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, 787137d3edbSTejun Heo unsigned int nents, unsigned int flags) 788137d3edbSTejun Heo { 789137d3edbSTejun Heo memset(miter, 0, sizeof(struct sg_mapping_iter)); 790137d3edbSTejun Heo 7914225fc85SImre Deak __sg_page_iter_start(&miter->piter, sgl, nents, 0); 7926de7e356SSebastian Andrzej Siewior WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); 793137d3edbSTejun Heo miter->__flags = flags; 794137d3edbSTejun Heo } 795137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_start); 796137d3edbSTejun Heo 79711052004SAkinobu Mita static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) 79811052004SAkinobu Mita { 79911052004SAkinobu Mita if (!miter->__remaining) { 80011052004SAkinobu Mita struct scatterlist *sg; 80111052004SAkinobu Mita 80211052004SAkinobu Mita if (!__sg_page_iter_next(&miter->piter)) 80311052004SAkinobu Mita return false; 80411052004SAkinobu Mita 80511052004SAkinobu Mita sg = miter->piter.sg; 80611052004SAkinobu Mita 807aeb87246SChristophe Leroy miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset; 808aeb87246SChristophe Leroy miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT; 809aeb87246SChristophe Leroy miter->__offset &= PAGE_SIZE - 1; 81011052004SAkinobu Mita miter->__remaining = sg->offset + sg->length - 811aeb87246SChristophe Leroy (miter->piter.sg_pgoffset << PAGE_SHIFT) - 812aeb87246SChristophe Leroy miter->__offset; 81311052004SAkinobu Mita miter->__remaining = min_t(unsigned long, miter->__remaining, 81411052004SAkinobu Mita PAGE_SIZE - miter->__offset); 81511052004SAkinobu Mita } 81611052004SAkinobu Mita 81711052004SAkinobu Mita return true; 81811052004SAkinobu Mita } 81911052004SAkinobu Mita 820137d3edbSTejun Heo /** 821df642ceaSAkinobu Mita * sg_miter_skip - reposition mapping iterator 822df642ceaSAkinobu Mita * @miter: sg mapping iter to be skipped 823df642ceaSAkinobu Mita * @offset: number of bytes to plus the current location 824df642ceaSAkinobu Mita * 825df642ceaSAkinobu Mita * Description: 826df642ceaSAkinobu Mita * Sets the offset of @miter to its current location plus @offset bytes. 827df642ceaSAkinobu Mita * If mapping iterator @miter has been proceeded by sg_miter_next(), this 828df642ceaSAkinobu Mita * stops @miter. 829df642ceaSAkinobu Mita * 830df642ceaSAkinobu Mita * Context: 831*723aca20SThomas Gleixner * Don't care. 832df642ceaSAkinobu Mita * 833df642ceaSAkinobu Mita * Returns: 834df642ceaSAkinobu Mita * true if @miter contains the valid mapping. false if end of sg 835df642ceaSAkinobu Mita * list is reached. 836df642ceaSAkinobu Mita */ 8370d6077f8SMing Lei bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) 838df642ceaSAkinobu Mita { 839df642ceaSAkinobu Mita sg_miter_stop(miter); 840df642ceaSAkinobu Mita 841df642ceaSAkinobu Mita while (offset) { 842df642ceaSAkinobu Mita off_t consumed; 843df642ceaSAkinobu Mita 844df642ceaSAkinobu Mita if (!sg_miter_get_next_page(miter)) 845df642ceaSAkinobu Mita return false; 846df642ceaSAkinobu Mita 847df642ceaSAkinobu Mita consumed = min_t(off_t, offset, miter->__remaining); 848df642ceaSAkinobu Mita miter->__offset += consumed; 849df642ceaSAkinobu Mita miter->__remaining -= consumed; 850df642ceaSAkinobu Mita offset -= consumed; 851df642ceaSAkinobu Mita } 852df642ceaSAkinobu Mita 853df642ceaSAkinobu Mita return true; 854df642ceaSAkinobu Mita } 8550d6077f8SMing Lei EXPORT_SYMBOL(sg_miter_skip); 856df642ceaSAkinobu Mita 857df642ceaSAkinobu Mita /** 858137d3edbSTejun Heo * sg_miter_next - proceed mapping iterator to the next mapping 859137d3edbSTejun Heo * @miter: sg mapping iter to proceed 860137d3edbSTejun Heo * 861137d3edbSTejun Heo * Description: 8628290e2d2STejun Heo * Proceeds @miter to the next mapping. @miter should have been started 8638290e2d2STejun Heo * using sg_miter_start(). On successful return, @miter->page, 8648290e2d2STejun Heo * @miter->addr and @miter->length point to the current mapping. 865137d3edbSTejun Heo * 866137d3edbSTejun Heo * Context: 867*723aca20SThomas Gleixner * May sleep if !SG_MITER_ATOMIC. 868137d3edbSTejun Heo * 869137d3edbSTejun Heo * Returns: 870137d3edbSTejun Heo * true if @miter contains the next mapping. false if end of sg 871137d3edbSTejun Heo * list is reached. 872137d3edbSTejun Heo */ 873137d3edbSTejun Heo bool sg_miter_next(struct sg_mapping_iter *miter) 874137d3edbSTejun Heo { 875137d3edbSTejun Heo sg_miter_stop(miter); 876137d3edbSTejun Heo 8774225fc85SImre Deak /* 8784225fc85SImre Deak * Get to the next page if necessary. 8794225fc85SImre Deak * __remaining, __offset is adjusted by sg_miter_stop 8804225fc85SImre Deak */ 88111052004SAkinobu Mita if (!sg_miter_get_next_page(miter)) 88223c560a9STejun Heo return false; 8834225fc85SImre Deak 8842db76d7cSImre Deak miter->page = sg_page_iter_page(&miter->piter); 8854225fc85SImre Deak miter->consumed = miter->length = miter->__remaining; 886137d3edbSTejun Heo 887137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) 8884225fc85SImre Deak miter->addr = kmap_atomic(miter->page) + miter->__offset; 889137d3edbSTejun Heo else 8904225fc85SImre Deak miter->addr = kmap(miter->page) + miter->__offset; 891137d3edbSTejun Heo 892137d3edbSTejun Heo return true; 893137d3edbSTejun Heo } 894137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_next); 895137d3edbSTejun Heo 896137d3edbSTejun Heo /** 897137d3edbSTejun Heo * sg_miter_stop - stop mapping iteration 898137d3edbSTejun Heo * @miter: sg mapping iter to be stopped 899137d3edbSTejun Heo * 900137d3edbSTejun Heo * Description: 901137d3edbSTejun Heo * Stops mapping iterator @miter. @miter should have been started 9024ba6a2b2SMasahiro Yamada * using sg_miter_start(). A stopped iteration can be resumed by 9034ba6a2b2SMasahiro Yamada * calling sg_miter_next() on it. This is useful when resources (kmap) 9044ba6a2b2SMasahiro Yamada * need to be released during iteration. 905137d3edbSTejun Heo * 906137d3edbSTejun Heo * Context: 907*723aca20SThomas Gleixner * Don't care otherwise. 908137d3edbSTejun Heo */ 909137d3edbSTejun Heo void sg_miter_stop(struct sg_mapping_iter *miter) 910137d3edbSTejun Heo { 911137d3edbSTejun Heo WARN_ON(miter->consumed > miter->length); 912137d3edbSTejun Heo 913137d3edbSTejun Heo /* drop resources from the last iteration */ 914137d3edbSTejun Heo if (miter->addr) { 915137d3edbSTejun Heo miter->__offset += miter->consumed; 9164225fc85SImre Deak miter->__remaining -= miter->consumed; 917137d3edbSTejun Heo 9180e84f5dbSChristoph Hellwig if (miter->__flags & SG_MITER_TO_SG) 9190e84f5dbSChristoph Hellwig flush_dcache_page(miter->page); 9206de7e356SSebastian Andrzej Siewior 921137d3edbSTejun Heo if (miter->__flags & SG_MITER_ATOMIC) { 922*723aca20SThomas Gleixner WARN_ON_ONCE(!pagefault_disabled()); 923c3eede8eSCong Wang kunmap_atomic(miter->addr); 924137d3edbSTejun Heo } else 925f652c521SArjan van de Ven kunmap(miter->page); 926137d3edbSTejun Heo 927137d3edbSTejun Heo miter->page = NULL; 928137d3edbSTejun Heo miter->addr = NULL; 929137d3edbSTejun Heo miter->length = 0; 930137d3edbSTejun Heo miter->consumed = 0; 931137d3edbSTejun Heo } 932137d3edbSTejun Heo } 933137d3edbSTejun Heo EXPORT_SYMBOL(sg_miter_stop); 934137d3edbSTejun Heo 935137d3edbSTejun Heo /** 936b1adaf65SFUJITA Tomonori * sg_copy_buffer - Copy data between a linear buffer and an SG list 937b1adaf65SFUJITA Tomonori * @sgl: The SG list 938b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 939b1adaf65SFUJITA Tomonori * @buf: Where to copy from 940b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 941df642ceaSAkinobu Mita * @skip: Number of bytes to skip before copying 942df642ceaSAkinobu Mita * @to_buffer: transfer direction (true == from an sg list to a 9436e853185SGeert Uytterhoeven * buffer, false == from a buffer to an sg list) 944b1adaf65SFUJITA Tomonori * 945b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 946b1adaf65SFUJITA Tomonori * 947b1adaf65SFUJITA Tomonori **/ 948386ecb12SDave Gordon size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, 949386ecb12SDave Gordon size_t buflen, off_t skip, bool to_buffer) 950b1adaf65SFUJITA Tomonori { 951137d3edbSTejun Heo unsigned int offset = 0; 952137d3edbSTejun Heo struct sg_mapping_iter miter; 9536de7e356SSebastian Andrzej Siewior unsigned int sg_flags = SG_MITER_ATOMIC; 954b1adaf65SFUJITA Tomonori 9556de7e356SSebastian Andrzej Siewior if (to_buffer) 9566de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_FROM_SG; 9576de7e356SSebastian Andrzej Siewior else 9586de7e356SSebastian Andrzej Siewior sg_flags |= SG_MITER_TO_SG; 9596de7e356SSebastian Andrzej Siewior 9606de7e356SSebastian Andrzej Siewior sg_miter_start(&miter, sgl, nents, sg_flags); 961b1adaf65SFUJITA Tomonori 962df642ceaSAkinobu Mita if (!sg_miter_skip(&miter, skip)) 9631f41be7dSDavid Disseldorp return 0; 964df642ceaSAkinobu Mita 9651d5210efSGilad Ben-Yossef while ((offset < buflen) && sg_miter_next(&miter)) { 966137d3edbSTejun Heo unsigned int len; 967b1adaf65SFUJITA Tomonori 968137d3edbSTejun Heo len = min(miter.length, buflen - offset); 969b1adaf65SFUJITA Tomonori 970b1adaf65SFUJITA Tomonori if (to_buffer) 971137d3edbSTejun Heo memcpy(buf + offset, miter.addr, len); 9726de7e356SSebastian Andrzej Siewior else 973137d3edbSTejun Heo memcpy(miter.addr, buf + offset, len); 974b1adaf65SFUJITA Tomonori 975137d3edbSTejun Heo offset += len; 976b1adaf65SFUJITA Tomonori } 977b1adaf65SFUJITA Tomonori 978137d3edbSTejun Heo sg_miter_stop(&miter); 979b1adaf65SFUJITA Tomonori 980137d3edbSTejun Heo return offset; 981b1adaf65SFUJITA Tomonori } 982386ecb12SDave Gordon EXPORT_SYMBOL(sg_copy_buffer); 983b1adaf65SFUJITA Tomonori 984b1adaf65SFUJITA Tomonori /** 985b1adaf65SFUJITA Tomonori * sg_copy_from_buffer - Copy from a linear buffer to an SG list 986b1adaf65SFUJITA Tomonori * @sgl: The SG list 987b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 988b1adaf65SFUJITA Tomonori * @buf: Where to copy from 989b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 990b1adaf65SFUJITA Tomonori * 991b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 992b1adaf65SFUJITA Tomonori * 993b1adaf65SFUJITA Tomonori **/ 994b1adaf65SFUJITA Tomonori size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, 9952a1bf8f9SDave Gordon const void *buf, size_t buflen) 996b1adaf65SFUJITA Tomonori { 9972a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); 998b1adaf65SFUJITA Tomonori } 999b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_from_buffer); 1000b1adaf65SFUJITA Tomonori 1001b1adaf65SFUJITA Tomonori /** 1002b1adaf65SFUJITA Tomonori * sg_copy_to_buffer - Copy from an SG list to a linear buffer 1003b1adaf65SFUJITA Tomonori * @sgl: The SG list 1004b1adaf65SFUJITA Tomonori * @nents: Number of SG entries 1005b1adaf65SFUJITA Tomonori * @buf: Where to copy to 1006b1adaf65SFUJITA Tomonori * @buflen: The number of bytes to copy 1007b1adaf65SFUJITA Tomonori * 1008b1adaf65SFUJITA Tomonori * Returns the number of copied bytes. 1009b1adaf65SFUJITA Tomonori * 1010b1adaf65SFUJITA Tomonori **/ 1011b1adaf65SFUJITA Tomonori size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, 1012b1adaf65SFUJITA Tomonori void *buf, size_t buflen) 1013b1adaf65SFUJITA Tomonori { 1014df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); 1015b1adaf65SFUJITA Tomonori } 1016b1adaf65SFUJITA Tomonori EXPORT_SYMBOL(sg_copy_to_buffer); 1017df642ceaSAkinobu Mita 1018df642ceaSAkinobu Mita /** 1019df642ceaSAkinobu Mita * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list 1020df642ceaSAkinobu Mita * @sgl: The SG list 1021df642ceaSAkinobu Mita * @nents: Number of SG entries 1022df642ceaSAkinobu Mita * @buf: Where to copy from 1023df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 10244dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 1025df642ceaSAkinobu Mita * 1026df642ceaSAkinobu Mita * Returns the number of copied bytes. 1027df642ceaSAkinobu Mita * 1028df642ceaSAkinobu Mita **/ 1029df642ceaSAkinobu Mita size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, 10302a1bf8f9SDave Gordon const void *buf, size_t buflen, off_t skip) 1031df642ceaSAkinobu Mita { 10322a1bf8f9SDave Gordon return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); 1033df642ceaSAkinobu Mita } 1034df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_from_buffer); 1035df642ceaSAkinobu Mita 1036df642ceaSAkinobu Mita /** 1037df642ceaSAkinobu Mita * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer 1038df642ceaSAkinobu Mita * @sgl: The SG list 1039df642ceaSAkinobu Mita * @nents: Number of SG entries 1040df642ceaSAkinobu Mita * @buf: Where to copy to 1041df642ceaSAkinobu Mita * @buflen: The number of bytes to copy 10424dc7daf8SDave Gordon * @skip: Number of bytes to skip before copying 1043df642ceaSAkinobu Mita * 1044df642ceaSAkinobu Mita * Returns the number of copied bytes. 1045df642ceaSAkinobu Mita * 1046df642ceaSAkinobu Mita **/ 1047df642ceaSAkinobu Mita size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, 1048df642ceaSAkinobu Mita void *buf, size_t buflen, off_t skip) 1049df642ceaSAkinobu Mita { 1050df642ceaSAkinobu Mita return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); 1051df642ceaSAkinobu Mita } 1052df642ceaSAkinobu Mita EXPORT_SYMBOL(sg_pcopy_to_buffer); 10530945e569SJohannes Thumshirn 10540945e569SJohannes Thumshirn /** 10550945e569SJohannes Thumshirn * sg_zero_buffer - Zero-out a part of a SG list 10560945e569SJohannes Thumshirn * @sgl: The SG list 10570945e569SJohannes Thumshirn * @nents: Number of SG entries 10580945e569SJohannes Thumshirn * @buflen: The number of bytes to zero out 10590945e569SJohannes Thumshirn * @skip: Number of bytes to skip before zeroing 10600945e569SJohannes Thumshirn * 10610945e569SJohannes Thumshirn * Returns the number of bytes zeroed. 10620945e569SJohannes Thumshirn **/ 10630945e569SJohannes Thumshirn size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, 10640945e569SJohannes Thumshirn size_t buflen, off_t skip) 10650945e569SJohannes Thumshirn { 10660945e569SJohannes Thumshirn unsigned int offset = 0; 10670945e569SJohannes Thumshirn struct sg_mapping_iter miter; 10680945e569SJohannes Thumshirn unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; 10690945e569SJohannes Thumshirn 10700945e569SJohannes Thumshirn sg_miter_start(&miter, sgl, nents, sg_flags); 10710945e569SJohannes Thumshirn 10720945e569SJohannes Thumshirn if (!sg_miter_skip(&miter, skip)) 10730945e569SJohannes Thumshirn return false; 10740945e569SJohannes Thumshirn 10750945e569SJohannes Thumshirn while (offset < buflen && sg_miter_next(&miter)) { 10760945e569SJohannes Thumshirn unsigned int len; 10770945e569SJohannes Thumshirn 10780945e569SJohannes Thumshirn len = min(miter.length, buflen - offset); 10790945e569SJohannes Thumshirn memset(miter.addr, 0, len); 10800945e569SJohannes Thumshirn 10810945e569SJohannes Thumshirn offset += len; 10820945e569SJohannes Thumshirn } 10830945e569SJohannes Thumshirn 10840945e569SJohannes Thumshirn sg_miter_stop(&miter); 10850945e569SJohannes Thumshirn return offset; 10860945e569SJohannes Thumshirn } 10870945e569SJohannes Thumshirn EXPORT_SYMBOL(sg_zero_buffer); 1088