1 /* 2 * Copyright(c) 2009 Intel Corporation. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program; if not, write to the Free Software Foundation, Inc., 15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 16 * 17 * Maintained at www.Open-FCoE.org 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/types.h> 22 #include <linux/scatterlist.h> 23 #include <linux/crc32.h> 24 25 #include <scsi/libfc.h> 26 27 #include "fc_libfc.h" 28 29 MODULE_AUTHOR("Open-FCoE.org"); 30 MODULE_DESCRIPTION("libfc"); 31 MODULE_LICENSE("GPL v2"); 32 33 unsigned int fc_debug_logging; 34 module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR); 35 MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels"); 36 37 /** 38 * libfc_init() - Initialize libfc.ko 39 */ 40 static int __init libfc_init(void) 41 { 42 int rc = 0; 43 44 rc = fc_setup_fcp(); 45 if (rc) 46 return rc; 47 48 rc = fc_setup_exch_mgr(); 49 if (rc) 50 goto destroy_pkt_cache; 51 52 rc = fc_setup_rport(); 53 if (rc) 54 goto destroy_em; 55 56 return rc; 57 destroy_em: 58 fc_destroy_exch_mgr(); 59 destroy_pkt_cache: 60 fc_destroy_fcp(); 61 return rc; 62 } 63 module_init(libfc_init); 64 65 /** 66 * libfc_exit() - Tear down libfc.ko 67 */ 68 static void __exit libfc_exit(void) 69 { 70 fc_destroy_fcp(); 71 fc_destroy_exch_mgr(); 72 fc_destroy_rport(); 73 } 74 module_exit(libfc_exit); 75 76 /** 77 * fc_copy_buffer_to_sglist() - This routine copies the data of a buffer 78 * into a scatter-gather list (SG list). 79 * 80 * @buf: pointer to the data buffer. 81 * @len: the byte-length of the data buffer. 82 * @sg: pointer to the pointer of the SG list. 83 * @nents: pointer to the remaining number of entries in the SG list. 84 * @offset: pointer to the current offset in the SG list. 85 * @km_type: dedicated page table slot type for kmap_atomic. 86 * @crc: pointer to the 32-bit crc value. 87 * If crc is NULL, CRC is not calculated. 88 */ 89 u32 fc_copy_buffer_to_sglist(void *buf, size_t len, 90 struct scatterlist *sg, 91 u32 *nents, size_t *offset, 92 enum km_type km_type, u32 *crc) 93 { 94 size_t remaining = len; 95 u32 copy_len = 0; 96 97 while (remaining > 0 && sg) { 98 size_t off, sg_bytes; 99 void *page_addr; 100 101 if (*offset >= sg->length) { 102 /* 103 * Check for end and drop resources 104 * from the last iteration. 105 */ 106 if (!(*nents)) 107 break; 108 --(*nents); 109 *offset -= sg->length; 110 sg = sg_next(sg); 111 continue; 112 } 113 sg_bytes = min(remaining, sg->length - *offset); 114 115 /* 116 * The scatterlist item may be bigger than PAGE_SIZE, 117 * but we are limited to mapping PAGE_SIZE at a time. 118 */ 119 off = *offset + sg->offset; 120 sg_bytes = min(sg_bytes, 121 (size_t)(PAGE_SIZE - (off & ~PAGE_MASK))); 122 page_addr = kmap_atomic(sg_page(sg) + (off >> PAGE_SHIFT), 123 km_type); 124 if (crc) 125 *crc = crc32(*crc, buf, sg_bytes); 126 memcpy((char *)page_addr + (off & ~PAGE_MASK), buf, sg_bytes); 127 kunmap_atomic(page_addr, km_type); 128 buf += sg_bytes; 129 *offset += sg_bytes; 130 remaining -= sg_bytes; 131 copy_len += sg_bytes; 132 } 133 return copy_len; 134 } 135