block/blk-lib.c

   1 /*
   2  * Functions related to generic helpers functions
   3  */
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/bio.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/scatterlist.h>
   9
  10 #include "blk.h"
  11
  12 struct bio_batch {
  13         atomic_t                done;
  14         unsigned long           flags;
  15         struct completion       *wait;
  16 };
  17
  18 static void bio_batch_end_io(struct bio *bio, int err,
  19                              struct batch_complete *batch)
  20 {
  21         struct bio_batch *bb = bio->bi_private;
  22
  23         if (err && (err != -EOPNOTSUPP))
  24                 clear_bit(BIO_UPTODATE, &bb->flags);
  25         if (atomic_dec_and_test(&bb->done))
  26                 complete(bb->wait);
  27         bio_put(bio);
  28 }
  29
  30 /**
  31  * blkdev_issue_discard - queue a discard
  32  * @bdev:       blockdev to issue discard for
  33  * @sector:     start sector
  34  * @nr_sects:   number of sectors to discard
  35  * @gfp_mask:   memory allocation flags (for bio_alloc)
  36  * @flags:      BLKDEV_IFL_* flags to control behaviour
  37  *
  38  * Description:
  39  *    Issue a discard request for the sectors in question.
  40  */
  41 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  42                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
  43 {
  44         DECLARE_COMPLETION_ONSTACK(wait);
  45         struct request_queue *q = bdev_get_queue(bdev);
  46         int type = REQ_WRITE | REQ_DISCARD;
  47         sector_t max_discard_sectors;
  48         sector_t granularity, alignment;
  49         struct bio_batch bb;
  50         struct bio *bio;
  51         int ret = 0;
  52         struct blk_plug plug;
  53
  54         if (!q)
  55                 return -ENXIO;
  56
  57         if (!blk_queue_discard(q))
  58                 return -EOPNOTSUPP;
  59
  60         /* Zero-sector (unknown) and one-sector granularities are the same.  */
  61         granularity = max(q->limits.discard_granularity >> 9, 1U);
  62         alignment = bdev_discard_alignment(bdev) >> 9;
  63         alignment = sector_div(alignment, granularity);
  64
  65         /*
  66          * Ensure that max_discard_sectors is of the proper
  67          * granularity, so that requests stay aligned after a split.
  68          */
  69         max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
  70         sector_div(max_discard_sectors, granularity);
  71         max_discard_sectors *= granularity;
  72         if (unlikely(!max_discard_sectors)) {
  73                 /* Avoid infinite loop below. Being cautious never hurts. */
  74                 return -EOPNOTSUPP;
  75         }
  76
  77         if (flags & BLKDEV_DISCARD_SECURE) {
  78                 if (!blk_queue_secdiscard(q))
  79                         return -EOPNOTSUPP;
  80                 type |= REQ_SECURE;
  81         }
  82
  83         atomic_set(&bb.done, 1);
  84         bb.flags = 1 << BIO_UPTODATE;
  85         bb.wait = &wait;
  86
  87         blk_start_plug(&plug);
  88         while (nr_sects) {
  89                 unsigned int req_sects;
  90                 sector_t end_sect, tmp;
  91
  92                 bio = bio_alloc(gfp_mask, 1);
  93                 if (!bio) {
  94                         ret = -ENOMEM;
  95                         break;
  96                 }
  97
  98                 req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
  99
 100                 /*
 101                  * If splitting a request, and the next starting sector would be
 102                  * misaligned, stop the discard at the previous aligned sector.
 103                  */
 104                 end_sect = sector + req_sects;
 105                 tmp = end_sect;
 106                 if (req_sects < nr_sects &&
 107                     sector_div(tmp, granularity) != alignment) {
 108                         end_sect = end_sect - alignment;
 109                         sector_div(end_sect, granularity);
 110                         end_sect = end_sect * granularity + alignment;
 111                         req_sects = end_sect - sector;
 112                 }
 113
 114                 bio->bi_sector = sector;
 115                 bio->bi_end_io = bio_batch_end_io;
 116                 bio->bi_bdev = bdev;
 117                 bio->bi_private = &bb;
 118
 119                 bio->bi_size = req_sects << 9;
 120                 nr_sects -= req_sects;
 121                 sector = end_sect;
 122
 123                 atomic_inc(&bb.done);
 124                 submit_bio(type, bio);
 125         }
 126         blk_finish_plug(&plug);
 127
 128         /* Wait for bios in-flight */
 129         if (!atomic_dec_and_test(&bb.done))
 130                 wait_for_completion_io(&wait);
 131
 132         if (!test_bit(BIO_UPTODATE, &bb.flags))
 133                 ret = -EIO;
 134
 135         return ret;
 136 }
 137 EXPORT_SYMBOL(blkdev_issue_discard);
 138
 139 /**
 140  * blkdev_issue_write_same - queue a write same operation
 141  * @bdev:       target blockdev
 142  * @sector:     start sector
 143  * @nr_sects:   number of sectors to write
 144  * @gfp_mask:   memory allocation flags (for bio_alloc)
 145  * @page:       page containing data to write
 146  *
 147  * Description:
 148  *    Issue a write same request for the sectors in question.
 149  */
 150 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 151                             sector_t nr_sects, gfp_t gfp_mask,
 152                             struct page *page)
 153 {
 154         DECLARE_COMPLETION_ONSTACK(wait);
 155         struct request_queue *q = bdev_get_queue(bdev);
 156         unsigned int max_write_same_sectors;
 157         struct bio_batch bb;
 158         struct bio *bio;
 159         int ret = 0;
 160
 161         if (!q)
 162                 return -ENXIO;
 163
 164         max_write_same_sectors = q->limits.max_write_same_sectors;
 165
 166         if (max_write_same_sectors == 0)
 167                 return -EOPNOTSUPP;
 168
 169         atomic_set(&bb.done, 1);
 170         bb.flags = 1 << BIO_UPTODATE;
 171         bb.wait = &wait;
 172
 173         while (nr_sects) {
 174                 bio = bio_alloc(gfp_mask, 1);
 175                 if (!bio) {
 176                         ret = -ENOMEM;
 177                         break;
 178                 }
 179
 180                 bio->bi_sector = sector;
 181                 bio->bi_end_io = bio_batch_end_io;
 182                 bio->bi_bdev = bdev;
 183                 bio->bi_private = &bb;
 184                 bio->bi_vcnt = 1;
 185                 bio->bi_io_vec->bv_page = page;
 186                 bio->bi_io_vec->bv_offset = 0;
 187                 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
 188
 189                 if (nr_sects > max_write_same_sectors) {
 190                         bio->bi_size = max_write_same_sectors << 9;
 191                         nr_sects -= max_write_same_sectors;
 192                         sector += max_write_same_sectors;
 193                 } else {
 194                         bio->bi_size = nr_sects << 9;
 195                         nr_sects = 0;
 196                 }
 197
 198                 atomic_inc(&bb.done);
 199                 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
 200         }
 201
 202         /* Wait for bios in-flight */
 203         if (!atomic_dec_and_test(&bb.done))
 204                 wait_for_completion_io(&wait);
 205
 206         if (!test_bit(BIO_UPTODATE, &bb.flags))
 207                 ret = -ENOTSUPP;
 208
 209         return ret;
 210 }
 211 EXPORT_SYMBOL(blkdev_issue_write_same);
 212
 213 /**
 214  * blkdev_issue_zeroout - generate number of zero filed write bios
 215  * @bdev:       blockdev to issue
 216  * @sector:     start sector
 217  * @nr_sects:   number of sectors to write
 218  * @gfp_mask:   memory allocation flags (for bio_alloc)
 219  *
 220  * Description:
 221  *  Generate and issue number of bios with zerofiled pages.
 222  */
 223
 224 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 225                         sector_t nr_sects, gfp_t gfp_mask)
 226 {
 227         int ret;
 228         struct bio *bio;
 229         struct bio_batch bb;
 230         unsigned int sz;
 231         DECLARE_COMPLETION_ONSTACK(wait);
 232
 233         atomic_set(&bb.done, 1);
 234         bb.flags = 1 << BIO_UPTODATE;
 235         bb.wait = &wait;
 236
 237         ret = 0;
 238         while (nr_sects != 0) {
 239                 bio = bio_alloc(gfp_mask,
 240                                 min(nr_sects, (sector_t)BIO_MAX_PAGES));
 241                 if (!bio) {
 242                         ret = -ENOMEM;
 243                         break;
 244                 }
 245
 246                 bio->bi_sector = sector;
 247                 bio->bi_bdev   = bdev;
 248                 bio->bi_end_io = bio_batch_end_io;
 249                 bio->bi_private = &bb;
 250
 251                 while (nr_sects != 0) {
 252                         sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
 253                         ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
 254                         nr_sects -= ret >> 9;
 255                         sector += ret >> 9;
 256                         if (ret < (sz << 9))
 257                                 break;
 258                 }
 259                 ret = 0;
 260                 atomic_inc(&bb.done);
 261                 submit_bio(WRITE, bio);
 262         }
 263
 264         /* Wait for bios in-flight */
 265         if (!atomic_dec_and_test(&bb.done))
 266                 wait_for_completion_io(&wait);
 267
 268         if (!test_bit(BIO_UPTODATE, &bb.flags))
 269                 /* One of bios in the batch was completed with error.*/
 270                 ret = -EIO;
 271
 272         return ret;
 273 }
 274
 275 /**
 276  * blkdev_issue_zeroout - zero-fill a block range
 277  * @bdev:       blockdev to write
 278  * @sector:     start sector
 279  * @nr_sects:   number of sectors to write
 280  * @gfp_mask:   memory allocation flags (for bio_alloc)
 281  *
 282  * Description:
 283  *  Generate and issue number of bios with zerofiled pages.
 284  */
 285
 286 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 287                          sector_t nr_sects, gfp_t gfp_mask)
 288 {
 289         if (bdev_write_same(bdev)) {
 290                 unsigned char bdn[BDEVNAME_SIZE];
 291
 292                 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
 293                                              ZERO_PAGE(0)))
 294                         return 0;
 295
 296                 bdevname(bdev, bdn);
 297                 pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
 298         }
 299
 300         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
 301 }
 302 EXPORT_SYMBOL(blkdev_issue_zeroout);