blk-integrity.c

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    1 /*
    2  * blk-integrity.c - Block layer data integrity extensions
    3  *
    4  * Copyright (C) 2007, 2008 Oracle Corporation
    5  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
    6  *
    7  * This program is free software; you can redistribute it and/or
    8  * modify it under the terms of the GNU General Public License version
    9  * 2 as published by the Free Software Foundation.
   10  *
   11  * This program is distributed in the hope that it will be useful, but
   12  * WITHOUT ANY WARRANTY; without even the implied warranty of
   13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   14  * General Public License for more details.
   15  *
   16  * You should have received a copy of the GNU General Public License
   17  * along with this program; see the file COPYING.  If not, write to
   18  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
   19  * USA.
   20  *
   21  */
   22 
   23 #include <linux/blkdev.h>
   24 #include <linux/mempool.h>
   25 #include <linux/bio.h>
   26 #include <linux/scatterlist.h>
   27 #include <linux/export.h>
   28 #include <linux/slab.h>
   29 
   30 #include "blk.h"
   31 
   32 static struct kmem_cache *integrity_cachep;
   33 
   34 static const char *bi_unsupported_name = "unsupported";
   35 
   36 /**
   37  * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements
   38  * @q:          request queue
   39  * @bio:        bio with integrity metadata attached
   40  *
   41  * Description: Returns the number of elements required in a
   42  * scatterlist corresponding to the integrity metadata in a bio.
   43  */
   44 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)
   45 {
   46         struct bio_vec *iv, *ivprv = NULL;
   47         unsigned int segments = 0;
   48         unsigned int seg_size = 0;
   49         unsigned int i = 0;
   50 
   51         bio_for_each_integrity_vec(iv, bio, i) {
   52 
   53                 if (ivprv) {
   54                         if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
   55                                 goto new_segment;
   56 
   57                         if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
   58                                 goto new_segment;
   59 
   60                         if (seg_size + iv->bv_len > queue_max_segment_size(q))
   61                                 goto new_segment;
   62 
   63                         seg_size += iv->bv_len;
   64                 } else {
   65 new_segment:
   66                         segments++;
   67                         seg_size = iv->bv_len;
   68                 }
   69 
   70                 ivprv = iv;
   71         }
   72 
   73         return segments;
   74 }
   75 EXPORT_SYMBOL(blk_rq_count_integrity_sg);
   76 
   77 /**
   78  * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist
   79  * @q:          request queue
   80  * @bio:        bio with integrity metadata attached
   81  * @sglist:     target scatterlist
   82  *
   83  * Description: Map the integrity vectors in request into a
   84  * scatterlist.  The scatterlist must be big enough to hold all
   85  * elements.  I.e. sized using blk_rq_count_integrity_sg().
   86  */
   87 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,
   88                             struct scatterlist *sglist)
   89 {
   90         struct bio_vec *iv, *ivprv = NULL;
   91         struct scatterlist *sg = NULL;
   92         unsigned int segments = 0;
   93         unsigned int i = 0;
   94 
   95         bio_for_each_integrity_vec(iv, bio, i) {
   96 
   97                 if (ivprv) {
   98                         if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv))
   99                                 goto new_segment;
  100 
  101                         if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv))
  102                                 goto new_segment;
  103 
  104                         if (sg->length + iv->bv_len > queue_max_segment_size(q))
  105                                 goto new_segment;
  106 
  107                         sg->length += iv->bv_len;
  108                 } else {
  109 new_segment:
  110                         if (!sg)
  111                                 sg = sglist;
  112                         else {
  113                                 sg->page_link &= ~0x02;
  114                                 sg = sg_next(sg);
  115                         }
  116 
  117                         sg_set_page(sg, iv->bv_page, iv->bv_len, iv->bv_offset);
  118                         segments++;
  119                 }
  120 
  121                 ivprv = iv;
  122         }
  123 
  124         if (sg)
  125                 sg_mark_end(sg);
  126 
  127         return segments;
  128 }
  129 EXPORT_SYMBOL(blk_rq_map_integrity_sg);
  130 
  131 /**
  132  * blk_integrity_compare - Compare integrity profile of two disks
  133  * @gd1:        Disk to compare
  134  * @gd2:        Disk to compare
  135  *
  136  * Description: Meta-devices like DM and MD need to verify that all
  137  * sub-devices use the same integrity format before advertising to
  138  * upper layers that they can send/receive integrity metadata.  This
  139  * function can be used to check whether two gendisk devices have
  140  * compatible integrity formats.
  141  */
  142 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2)
  143 {
  144         struct blk_integrity *b1 = gd1->integrity;
  145         struct blk_integrity *b2 = gd2->integrity;
  146 
  147         if (!b1 && !b2)
  148                 return 0;
  149 
  150         if (!b1 || !b2)
  151                 return -1;
  152 
  153         if (b1->sector_size != b2->sector_size) {
  154                 printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__,
  155                        gd1->disk_name, gd2->disk_name,
  156                        b1->sector_size, b2->sector_size);
  157                 return -1;
  158         }
  159 
  160         if (b1->tuple_size != b2->tuple_size) {
  161                 printk(KERN_ERR "%s: %s/%s tuple sz %u != %u\n", __func__,
  162                        gd1->disk_name, gd2->disk_name,
  163                        b1->tuple_size, b2->tuple_size);
  164                 return -1;
  165         }
  166 
  167         if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) {
  168                 printk(KERN_ERR "%s: %s/%s tag sz %u != %u\n", __func__,
  169                        gd1->disk_name, gd2->disk_name,
  170                        b1->tag_size, b2->tag_size);
  171                 return -1;
  172         }
  173 
  174         if (strcmp(b1->name, b2->name)) {
  175                 printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__,
  176                        gd1->disk_name, gd2->disk_name,
  177                        b1->name, b2->name);
  178                 return -1;
  179         }
  180 
  181         return 0;
  182 }
  183 EXPORT_SYMBOL(blk_integrity_compare);
  184 
  185 int blk_integrity_merge_rq(struct request_queue *q, struct request *req,
  186                            struct request *next)
  187 {
  188         if (blk_integrity_rq(req) != blk_integrity_rq(next))
  189                 return -1;
  190 
  191         if (req->nr_integrity_segments + next->nr_integrity_segments >
  192             q->limits.max_integrity_segments)
  193                 return -1;
  194 
  195         return 0;
  196 }
  197 EXPORT_SYMBOL(blk_integrity_merge_rq);
  198 
  199 int blk_integrity_merge_bio(struct request_queue *q, struct request *req,
  200                             struct bio *bio)
  201 {
  202         int nr_integrity_segs;
  203         struct bio *next = bio->bi_next;
  204 
  205         bio->bi_next = NULL;
  206         nr_integrity_segs = blk_rq_count_integrity_sg(q, bio);
  207         bio->bi_next = next;
  208 
  209         if (req->nr_integrity_segments + nr_integrity_segs >
  210             q->limits.max_integrity_segments)
  211                 return -1;
  212 
  213         req->nr_integrity_segments += nr_integrity_segs;
  214 
  215         return 0;
  216 }
  217 EXPORT_SYMBOL(blk_integrity_merge_bio);
  218 
  219 struct integrity_sysfs_entry {
  220         struct attribute attr;
  221         ssize_t (*show)(struct blk_integrity *, char *);
  222         ssize_t (*store)(struct blk_integrity *, const char *, size_t);
  223 };
  224 
  225 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr,
  226                                    char *page)
  227 {
  228         struct blk_integrity *bi =
  229                 container_of(kobj, struct blk_integrity, kobj);
  230         struct integrity_sysfs_entry *entry =
  231                 container_of(attr, struct integrity_sysfs_entry, attr);
  232 
  233         return entry->show(bi, page);
  234 }
  235 
  236 static ssize_t integrity_attr_store(struct kobject *kobj,
  237                                     struct attribute *attr, const char *page,
  238                                     size_t count)
  239 {
  240         struct blk_integrity *bi =
  241                 container_of(kobj, struct blk_integrity, kobj);
  242         struct integrity_sysfs_entry *entry =
  243                 container_of(attr, struct integrity_sysfs_entry, attr);
  244         ssize_t ret = 0;
  245 
  246         if (entry->store)
  247                 ret = entry->store(bi, page, count);
  248 
  249         return ret;
  250 }
  251 
  252 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page)
  253 {
  254         if (bi != NULL && bi->name != NULL)
  255                 return sprintf(page, "%s\n", bi->name);
  256         else
  257                 return sprintf(page, "none\n");
  258 }
  259 
  260 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page)
  261 {
  262         if (bi != NULL)
  263                 return sprintf(page, "%u\n", bi->tag_size);
  264         else
  265                 return sprintf(page, "\n");
  266 }
  267 
  268 static ssize_t integrity_read_store(struct blk_integrity *bi,
  269                                     const char *page, size_t count)
  270 {
  271         char *p = (char *) page;
  272         unsigned long val = simple_strtoul(p, &p, 10);
  273 
  274         if (val)
  275                 bi->flags |= INTEGRITY_FLAG_READ;
  276         else
  277                 bi->flags &= ~INTEGRITY_FLAG_READ;
  278 
  279         return count;
  280 }
  281 
  282 static ssize_t integrity_read_show(struct blk_integrity *bi, char *page)
  283 {
  284         return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_READ) != 0);
  285 }
  286 
  287 static ssize_t integrity_write_store(struct blk_integrity *bi,
  288                                      const char *page, size_t count)
  289 {
  290         char *p = (char *) page;
  291         unsigned long val = simple_strtoul(p, &p, 10);
  292 
  293         if (val)
  294                 bi->flags |= INTEGRITY_FLAG_WRITE;
  295         else
  296                 bi->flags &= ~INTEGRITY_FLAG_WRITE;
  297 
  298         return count;
  299 }
  300 
  301 static ssize_t integrity_write_show(struct blk_integrity *bi, char *page)
  302 {
  303         return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_WRITE) != 0);
  304 }
  305 
  306 static struct integrity_sysfs_entry integrity_format_entry = {
  307         .attr = { .name = "format", .mode = S_IRUGO },
  308         .show = integrity_format_show,
  309 };
  310 
  311 static struct integrity_sysfs_entry integrity_tag_size_entry = {
  312         .attr = { .name = "tag_size", .mode = S_IRUGO },
  313         .show = integrity_tag_size_show,
  314 };
  315 
  316 static struct integrity_sysfs_entry integrity_read_entry = {
  317         .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR },
  318         .show = integrity_read_show,
  319         .store = integrity_read_store,
  320 };
  321 
  322 static struct integrity_sysfs_entry integrity_write_entry = {
  323         .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR },
  324         .show = integrity_write_show,
  325         .store = integrity_write_store,
  326 };
  327 
  328 static struct attribute *integrity_attrs[] = {
  329         &integrity_format_entry.attr,
  330         &integrity_tag_size_entry.attr,
  331         &integrity_read_entry.attr,
  332         &integrity_write_entry.attr,
  333         NULL,
  334 };
  335 
  336 static const struct sysfs_ops integrity_ops = {
  337         .show   = &integrity_attr_show,
  338         .store  = &integrity_attr_store,
  339 };
  340 
  341 static int __init blk_dev_integrity_init(void)
  342 {
  343         integrity_cachep = kmem_cache_create("blkdev_integrity",
  344                                              sizeof(struct blk_integrity),
  345                                              0, SLAB_PANIC, NULL);
  346         return 0;
  347 }
  348 subsys_initcall(blk_dev_integrity_init);
  349 
  350 static void blk_integrity_release(struct kobject *kobj)
  351 {
  352         struct blk_integrity *bi =
  353                 container_of(kobj, struct blk_integrity, kobj);
  354 
  355         kmem_cache_free(integrity_cachep, bi);
  356 }
  357 
  358 static struct kobj_type integrity_ktype = {
  359         .default_attrs  = integrity_attrs,
  360         .sysfs_ops      = &integrity_ops,
  361         .release        = blk_integrity_release,
  362 };
  363 
  364 bool blk_integrity_is_initialized(struct gendisk *disk)
  365 {
  366         struct blk_integrity *bi = blk_get_integrity(disk);
  367 
  368         return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0);
  369 }
  370 EXPORT_SYMBOL(blk_integrity_is_initialized);
  371 
  372 /**
  373  * blk_integrity_register - Register a gendisk as being integrity-capable
  374  * @disk:       struct gendisk pointer to make integrity-aware
  375  * @template:   optional integrity profile to register
  376  *
  377  * Description: When a device needs to advertise itself as being able
  378  * to send/receive integrity metadata it must use this function to
  379  * register the capability with the block layer.  The template is a
  380  * blk_integrity struct with values appropriate for the underlying
  381  * hardware.  If template is NULL the new profile is allocated but
  382  * not filled out. See Documentation/block/data-integrity.txt.
  383  */
  384 int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
  385 {
  386         struct blk_integrity *bi;
  387 
  388         BUG_ON(disk == NULL);
  389 
  390         if (disk->integrity == NULL) {
  391                 bi = kmem_cache_alloc(integrity_cachep,
  392                                       GFP_KERNEL | __GFP_ZERO);
  393                 if (!bi)
  394                         return -1;
  395 
  396                 if (kobject_init_and_add(&bi->kobj, &integrity_ktype,
  397                                          &disk_to_dev(disk)->kobj,
  398                                          "%s", "integrity")) {
  399                         kmem_cache_free(integrity_cachep, bi);
  400                         return -1;
  401                 }
  402 
  403                 kobject_uevent(&bi->kobj, KOBJ_ADD);
  404 
  405                 bi->flags |= INTEGRITY_FLAG_READ | INTEGRITY_FLAG_WRITE;
  406                 bi->sector_size = queue_logical_block_size(disk->queue);
  407                 disk->integrity = bi;
  408         } else
  409                 bi = disk->integrity;
  410 
  411         /* Use the provided profile as template */
  412         if (template != NULL) {
  413                 bi->name = template->name;
  414                 bi->generate_fn = template->generate_fn;
  415                 bi->verify_fn = template->verify_fn;
  416                 bi->tuple_size = template->tuple_size;
  417                 bi->set_tag_fn = template->set_tag_fn;
  418                 bi->get_tag_fn = template->get_tag_fn;
  419                 bi->tag_size = template->tag_size;
  420         } else
  421                 bi->name = bi_unsupported_name;
  422 
  423         return 0;
  424 }
  425 EXPORT_SYMBOL(blk_integrity_register);
  426 
  427 /**
  428  * blk_integrity_unregister - Remove block integrity profile
  429  * @disk:       disk whose integrity profile to deallocate
  430  *
  431  * Description: This function frees all memory used by the block
  432  * integrity profile.  To be called at device teardown.
  433  */
  434 void blk_integrity_unregister(struct gendisk *disk)
  435 {
  436         struct blk_integrity *bi;
  437 
  438         if (!disk || !disk->integrity)
  439                 return;
  440 
  441         bi = disk->integrity;
  442 
  443         kobject_uevent(&bi->kobj, KOBJ_REMOVE);
  444         kobject_del(&bi->kobj);
  445         kobject_put(&bi->kobj);
  446         disk->integrity = NULL;
  447 }
  448 EXPORT_SYMBOL(blk_integrity_unregister);
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FreeBSD/Linux Kernel Cross Reference sys/block/blk-integrity.c

FreeBSD/Linux Kernel Cross Reference
sys/block/blk-integrity.c
