scatterlist.h revision 289644
1219820Sjeff/*- 2219820Sjeff * Copyright (c) 2010 Isilon Systems, Inc. 3219820Sjeff * Copyright (c) 2010 iX Systems, Inc. 4219820Sjeff * Copyright (c) 2010 Panasas, Inc. 5270710Shselasky * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd. 6289567Shselasky * Copyright (c) 2015 Matthew Dillon <dillon@backplane.com> 7219820Sjeff * All rights reserved. 8219820Sjeff * 9219820Sjeff * Redistribution and use in source and binary forms, with or without 10219820Sjeff * modification, are permitted provided that the following conditions 11219820Sjeff * are met: 12219820Sjeff * 1. Redistributions of source code must retain the above copyright 13219820Sjeff * notice unmodified, this list of conditions, and the following 14219820Sjeff * disclaimer. 15219820Sjeff * 2. Redistributions in binary form must reproduce the above copyright 16219820Sjeff * notice, this list of conditions and the following disclaimer in the 17219820Sjeff * documentation and/or other materials provided with the distribution. 18219820Sjeff * 19219820Sjeff * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20219820Sjeff * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21219820Sjeff * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22219820Sjeff * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23219820Sjeff * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24219820Sjeff * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25219820Sjeff * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26219820Sjeff * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27219820Sjeff * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28219820Sjeff * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29289644Shselasky * 30289644Shselasky * $FreeBSD: head/sys/ofed/include/linux/scatterlist.h 289644 2015-10-20 19:08:26Z hselasky $ 31219820Sjeff */ 32219820Sjeff#ifndef _LINUX_SCATTERLIST_H_ 33219820Sjeff#define _LINUX_SCATTERLIST_H_ 34219820Sjeff 35219820Sjeff#include <linux/page.h> 36273135Shselasky#include <linux/slab.h> 37219820Sjeff 38273135Shselasky/* 39273135Shselasky * SG table design. 40273135Shselasky * 41273135Shselasky * If flags bit 0 is set, then the sg field contains a pointer to the next sg 42273135Shselasky * table list. Otherwise the next entry is at sg + 1, can be determined using 43273135Shselasky * the sg_is_chain() function. 44273135Shselasky * 45273135Shselasky * If flags bit 1 is set, then this sg entry is the last element in a list, 46273135Shselasky * can be determined using the sg_is_last() function. 47273135Shselasky * 48273135Shselasky * See sg_next(). 49273135Shselasky * 50273135Shselasky */ 51273135Shselasky 52219820Sjeffstruct scatterlist { 53219820Sjeff union { 54219820Sjeff struct page *page; 55219820Sjeff struct scatterlist *sg; 56219820Sjeff } sl_un; 57219846Skib dma_addr_t address; 58219820Sjeff unsigned long offset; 59219820Sjeff uint32_t length; 60219820Sjeff uint32_t flags; 61219820Sjeff}; 62219820Sjeff 63270710Shselaskystruct sg_table { 64270710Shselasky struct scatterlist *sgl; /* the list */ 65270710Shselasky unsigned int nents; /* number of mapped entries */ 66270710Shselasky unsigned int orig_nents; /* original size of list */ 67270710Shselasky}; 68270710Shselasky 69289567Shselaskystruct sg_page_iter { 70289567Shselasky struct scatterlist *sg; 71289567Shselasky unsigned int sg_pgoffset; /* page index */ 72289567Shselasky unsigned int maxents; 73289567Shselasky}; 74289567Shselasky 75273135Shselasky/* 76273135Shselasky * Maximum number of entries that will be allocated in one piece, if 77273135Shselasky * a list larger than this is required then chaining will be utilized. 78273135Shselasky */ 79273135Shselasky#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) 80273135Shselasky 81219820Sjeff#define sg_dma_address(sg) (sg)->address 82219820Sjeff#define sg_dma_len(sg) (sg)->length 83219820Sjeff#define sg_page(sg) (sg)->sl_un.page 84219820Sjeff#define sg_scatternext(sg) (sg)->sl_un.sg 85219820Sjeff 86219820Sjeff#define SG_END 0x01 87219820Sjeff#define SG_CHAIN 0x02 88219820Sjeff 89219820Sjeffstatic inline void 90219820Sjeffsg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, 91219820Sjeff unsigned int offset) 92219820Sjeff{ 93219820Sjeff sg_page(sg) = page; 94219820Sjeff sg_dma_len(sg) = len; 95219820Sjeff sg->offset = offset; 96219820Sjeff if (offset > PAGE_SIZE) 97219820Sjeff panic("sg_set_page: Invalid offset %d\n", offset); 98219820Sjeff} 99219820Sjeff 100219820Sjeffstatic inline void 101219820Sjeffsg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen) 102219820Sjeff{ 103219820Sjeff sg_set_page(sg, virt_to_page(buf), buflen, 104289567Shselasky ((uintptr_t)buf) & (PAGE_SIZE - 1)); 105219820Sjeff} 106219820Sjeff 107219820Sjeffstatic inline void 108219820Sjeffsg_init_table(struct scatterlist *sg, unsigned int nents) 109219820Sjeff{ 110219820Sjeff bzero(sg, sizeof(*sg) * nents); 111219820Sjeff sg[nents - 1].flags = SG_END; 112219820Sjeff} 113219820Sjeff 114219820Sjeffstatic inline struct scatterlist * 115219820Sjeffsg_next(struct scatterlist *sg) 116219820Sjeff{ 117219820Sjeff if (sg->flags & SG_END) 118219820Sjeff return (NULL); 119219820Sjeff sg++; 120219820Sjeff if (sg->flags & SG_CHAIN) 121219820Sjeff sg = sg_scatternext(sg); 122219820Sjeff return (sg); 123219820Sjeff} 124219820Sjeff 125219820Sjeffstatic inline vm_paddr_t 126219820Sjeffsg_phys(struct scatterlist *sg) 127219820Sjeff{ 128219820Sjeff return sg_page(sg)->phys_addr + sg->offset; 129219820Sjeff} 130219820Sjeff 131273135Shselasky/** 132273135Shselasky * sg_chain - Chain two sglists together 133273135Shselasky * @prv: First scatterlist 134273135Shselasky * @prv_nents: Number of entries in prv 135273135Shselasky * @sgl: Second scatterlist 136273135Shselasky * 137273135Shselasky * Description: 138273135Shselasky * Links @prv@ and @sgl@ together, to form a longer scatterlist. 139273135Shselasky * 140273135Shselasky **/ 141273135Shselaskystatic inline void 142273135Shselaskysg_chain(struct scatterlist *prv, unsigned int prv_nents, 143273135Shselasky struct scatterlist *sgl) 144273135Shselasky{ 145273135Shselasky/* 146273135Shselasky * offset and length are unused for chain entry. Clear them. 147273135Shselasky */ 148273135Shselasky struct scatterlist *sg = &prv[prv_nents - 1]; 149273135Shselasky 150273135Shselasky sg->offset = 0; 151273135Shselasky sg->length = 0; 152273135Shselasky 153273135Shselasky /* 154273135Shselasky * Indicate a link pointer, and set the link to the second list. 155273135Shselasky */ 156273135Shselasky sg->flags = SG_CHAIN; 157273135Shselasky sg->sl_un.sg = sgl; 158273135Shselasky} 159273135Shselasky 160273135Shselasky/** 161273135Shselasky * sg_mark_end - Mark the end of the scatterlist 162273135Shselasky * @sg: SG entryScatterlist 163273135Shselasky * 164273135Shselasky * Description: 165273135Shselasky * Marks the passed in sg entry as the termination point for the sg 166273135Shselasky * table. A call to sg_next() on this entry will return NULL. 167273135Shselasky * 168273135Shselasky **/ 169273135Shselaskystatic inline void sg_mark_end(struct scatterlist *sg) 170273135Shselasky{ 171273135Shselasky sg->flags = SG_END; 172273135Shselasky} 173273135Shselasky 174273135Shselasky/** 175273135Shselasky * __sg_free_table - Free a previously mapped sg table 176273135Shselasky * @table: The sg table header to use 177273135Shselasky * @max_ents: The maximum number of entries per single scatterlist 178273135Shselasky * 179273135Shselasky * Description: 180273135Shselasky * Free an sg table previously allocated and setup with 181273135Shselasky * __sg_alloc_table(). The @max_ents value must be identical to 182273135Shselasky * that previously used with __sg_alloc_table(). 183273135Shselasky * 184273135Shselasky **/ 185273135Shselaskystatic inline void 186273135Shselasky__sg_free_table(struct sg_table *table, unsigned int max_ents) 187273135Shselasky{ 188273135Shselasky struct scatterlist *sgl, *next; 189273135Shselasky 190273135Shselasky if (unlikely(!table->sgl)) 191273135Shselasky return; 192273135Shselasky 193273135Shselasky sgl = table->sgl; 194273135Shselasky while (table->orig_nents) { 195273135Shselasky unsigned int alloc_size = table->orig_nents; 196273135Shselasky unsigned int sg_size; 197273135Shselasky 198273135Shselasky /* 199273135Shselasky * If we have more than max_ents segments left, 200273135Shselasky * then assign 'next' to the sg table after the current one. 201273135Shselasky * sg_size is then one less than alloc size, since the last 202273135Shselasky * element is the chain pointer. 203273135Shselasky */ 204273135Shselasky if (alloc_size > max_ents) { 205273135Shselasky next = sgl[max_ents - 1].sl_un.sg; 206273135Shselasky alloc_size = max_ents; 207273135Shselasky sg_size = alloc_size - 1; 208273135Shselasky } else { 209273135Shselasky sg_size = alloc_size; 210273135Shselasky next = NULL; 211273135Shselasky } 212273135Shselasky 213273135Shselasky table->orig_nents -= sg_size; 214273135Shselasky kfree(sgl); 215273135Shselasky sgl = next; 216273135Shselasky } 217273135Shselasky 218273135Shselasky table->sgl = NULL; 219273135Shselasky} 220273135Shselasky 221273135Shselasky/** 222273135Shselasky * sg_free_table - Free a previously allocated sg table 223273135Shselasky * @table: The mapped sg table header 224273135Shselasky * 225273135Shselasky **/ 226273135Shselaskystatic inline void 227273135Shselaskysg_free_table(struct sg_table *table) 228273135Shselasky{ 229273135Shselasky __sg_free_table(table, SG_MAX_SINGLE_ALLOC); 230273135Shselasky} 231273135Shselasky 232273135Shselasky/** 233273135Shselasky * __sg_alloc_table - Allocate and initialize an sg table with given allocator 234273135Shselasky * @table: The sg table header to use 235273135Shselasky * @nents: Number of entries in sg list 236273135Shselasky * @max_ents: The maximum number of entries the allocator returns per call 237273135Shselasky * @gfp_mask: GFP allocation mask 238273135Shselasky * 239273135Shselasky * Description: 240273135Shselasky * This function returns a @table @nents long. The allocator is 241273135Shselasky * defined to return scatterlist chunks of maximum size @max_ents. 242273135Shselasky * Thus if @nents is bigger than @max_ents, the scatterlists will be 243273135Shselasky * chained in units of @max_ents. 244273135Shselasky * 245273135Shselasky * Notes: 246273135Shselasky * If this function returns non-0 (eg failure), the caller must call 247273135Shselasky * __sg_free_table() to cleanup any leftover allocations. 248273135Shselasky * 249273135Shselasky **/ 250273135Shselaskystatic inline int 251273135Shselasky__sg_alloc_table(struct sg_table *table, unsigned int nents, 252273135Shselasky unsigned int max_ents, gfp_t gfp_mask) 253273135Shselasky{ 254273135Shselasky struct scatterlist *sg, *prv; 255273135Shselasky unsigned int left; 256273135Shselasky 257273135Shselasky memset(table, 0, sizeof(*table)); 258273135Shselasky 259273135Shselasky if (nents == 0) 260273135Shselasky return -EINVAL; 261273135Shselasky left = nents; 262273135Shselasky prv = NULL; 263273135Shselasky do { 264273135Shselasky unsigned int sg_size, alloc_size = left; 265273135Shselasky 266273135Shselasky if (alloc_size > max_ents) { 267273135Shselasky alloc_size = max_ents; 268273135Shselasky sg_size = alloc_size - 1; 269273135Shselasky } else 270273135Shselasky sg_size = alloc_size; 271273135Shselasky 272273135Shselasky left -= sg_size; 273273135Shselasky 274273135Shselasky sg = kmalloc(alloc_size * sizeof(struct scatterlist), gfp_mask); 275273135Shselasky if (unlikely(!sg)) { 276273135Shselasky /* 277273135Shselasky * Adjust entry count to reflect that the last 278273135Shselasky * entry of the previous table won't be used for 279273135Shselasky * linkage. Without this, sg_kfree() may get 280273135Shselasky * confused. 281273135Shselasky */ 282273135Shselasky if (prv) 283273135Shselasky table->nents = ++table->orig_nents; 284273135Shselasky 285273135Shselasky return -ENOMEM; 286273135Shselasky } 287273135Shselasky 288273135Shselasky sg_init_table(sg, alloc_size); 289273135Shselasky table->nents = table->orig_nents += sg_size; 290273135Shselasky 291273135Shselasky /* 292273135Shselasky * If this is the first mapping, assign the sg table header. 293273135Shselasky * If this is not the first mapping, chain previous part. 294273135Shselasky */ 295273135Shselasky if (prv) 296273135Shselasky sg_chain(prv, max_ents, sg); 297273135Shselasky else 298273135Shselasky table->sgl = sg; 299273135Shselasky 300273135Shselasky /* 301273135Shselasky * If no more entries after this one, mark the end 302273135Shselasky */ 303273135Shselasky if (!left) 304273135Shselasky sg_mark_end(&sg[sg_size - 1]); 305273135Shselasky 306273135Shselasky prv = sg; 307273135Shselasky } while (left); 308273135Shselasky 309273135Shselasky return 0; 310273135Shselasky} 311273135Shselasky 312273135Shselasky/** 313273135Shselasky * sg_alloc_table - Allocate and initialize an sg table 314273135Shselasky * @table: The sg table header to use 315273135Shselasky * @nents: Number of entries in sg list 316273135Shselasky * @gfp_mask: GFP allocation mask 317273135Shselasky * 318273135Shselasky * Description: 319273135Shselasky * Allocate and initialize an sg table. If @nents@ is larger than 320273135Shselasky * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. 321273135Shselasky * 322273135Shselasky **/ 323273135Shselasky 324273135Shselaskystatic inline int 325273135Shselaskysg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) 326273135Shselasky{ 327273135Shselasky int ret; 328273135Shselasky 329273135Shselasky ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, 330273135Shselasky gfp_mask); 331273135Shselasky if (unlikely(ret)) 332273135Shselasky __sg_free_table(table, SG_MAX_SINGLE_ALLOC); 333273135Shselasky 334273135Shselasky return ret; 335273135Shselasky} 336273135Shselasky 337289567Shselasky/* 338289567Shselasky * Iterate pages in sg list. 339289567Shselasky */ 340289567Shselaskystatic inline void 341289567Shselasky_sg_iter_next(struct sg_page_iter *iter) 342289567Shselasky{ 343289567Shselasky struct scatterlist *sg; 344289567Shselasky unsigned int pgcount; 345289567Shselasky 346289567Shselasky sg = iter->sg; 347289567Shselasky pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT; 348289567Shselasky 349289567Shselasky ++iter->sg_pgoffset; 350289567Shselasky while (iter->sg_pgoffset >= pgcount) { 351289567Shselasky iter->sg_pgoffset -= pgcount; 352289567Shselasky sg = sg_next(sg); 353289567Shselasky --iter->maxents; 354289567Shselasky if (sg == NULL || iter->maxents == 0) 355289567Shselasky break; 356289567Shselasky pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT; 357289567Shselasky } 358289567Shselasky iter->sg = sg; 359289567Shselasky} 360289567Shselasky 361289567Shselasky/* 362289567Shselasky * NOTE: pgoffset is really a page index, not a byte offset. 363289567Shselasky */ 364289567Shselaskystatic inline void 365289567Shselasky_sg_iter_init(struct scatterlist *sgl, struct sg_page_iter *iter, 366289567Shselasky unsigned int nents, unsigned long pgoffset) 367289567Shselasky{ 368289567Shselasky if (nents) { 369289567Shselasky /* 370289567Shselasky * Nominal case. Note subtract 1 from starting page index 371289567Shselasky * for initial _sg_iter_next() call. 372289567Shselasky */ 373289567Shselasky iter->sg = sgl; 374289567Shselasky iter->sg_pgoffset = pgoffset - 1; 375289567Shselasky iter->maxents = nents; 376289567Shselasky _sg_iter_next(iter); 377289567Shselasky } else { 378289567Shselasky /* 379289567Shselasky * Degenerate case 380289567Shselasky */ 381289567Shselasky iter->sg = NULL; 382289567Shselasky iter->sg_pgoffset = 0; 383289567Shselasky iter->maxents = 0; 384289567Shselasky } 385289567Shselasky} 386289567Shselasky 387289567Shselaskystatic inline dma_addr_t 388289567Shselaskysg_page_iter_dma_address(struct sg_page_iter *spi) 389289567Shselasky{ 390289567Shselasky return spi->sg->address + (spi->sg_pgoffset << PAGE_SHIFT); 391289567Shselasky} 392289567Shselasky 393289567Shselasky#define for_each_sg_page(sgl, iter, nents, pgoffset) \ 394289567Shselasky for (_sg_iter_init(sgl, iter, nents, pgoffset); \ 395289567Shselasky (iter)->sg; _sg_iter_next(iter)) 396289567Shselasky 397219820Sjeff#define for_each_sg(sglist, sg, sgmax, _itr) \ 398219820Sjeff for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg)) 399219820Sjeff 400219820Sjeff#endif /* _LINUX_SCATTERLIST_H_ */ 401