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-rw-r--r--block/blk-lib.c317
1 files changed, 317 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
new file mode 100644
index 000000000..7688ee3f5
--- /dev/null
+++ b/block/blk-lib.c
@@ -0,0 +1,317 @@
+/*
+ * Functions related to generic helpers functions
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/scatterlist.h>
+
+#include "blk.h"
+
+struct bio_batch {
+ atomic_t done;
+ unsigned long flags;
+ struct completion *wait;
+};
+
+static void bio_batch_end_io(struct bio *bio, int err)
+{
+ struct bio_batch *bb = bio->bi_private;
+
+ if (err && (err != -EOPNOTSUPP))
+ clear_bit(BIO_UPTODATE, &bb->flags);
+ if (atomic_dec_and_test(&bb->done))
+ complete(bb->wait);
+ bio_put(bio);
+}
+
+/**
+ * blkdev_issue_discard - queue a discard
+ * @bdev: blockdev to issue discard for
+ * @sector: start sector
+ * @nr_sects: number of sectors to discard
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @flags: BLKDEV_IFL_* flags to control behaviour
+ *
+ * Description:
+ * Issue a discard request for the sectors in question.
+ */
+int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q = bdev_get_queue(bdev);
+ int type = REQ_WRITE | REQ_DISCARD;
+ unsigned int max_discard_sectors, granularity;
+ int alignment;
+ struct bio_batch bb;
+ struct bio *bio;
+ int ret = 0;
+ struct blk_plug plug;
+
+ if (!q)
+ return -ENXIO;
+
+ if (!blk_queue_discard(q))
+ return -EOPNOTSUPP;
+
+ /* Zero-sector (unknown) and one-sector granularities are the same. */
+ granularity = max(q->limits.discard_granularity >> 9, 1U);
+ alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
+
+ /*
+ * Ensure that max_discard_sectors is of the proper
+ * granularity, so that requests stay aligned after a split.
+ */
+ max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+ max_discard_sectors -= max_discard_sectors % granularity;
+ if (unlikely(!max_discard_sectors)) {
+ /* Avoid infinite loop below. Being cautious never hurts. */
+ return -EOPNOTSUPP;
+ }
+
+ if (flags & BLKDEV_DISCARD_SECURE) {
+ if (!blk_queue_secdiscard(q))
+ return -EOPNOTSUPP;
+ type |= REQ_SECURE;
+ }
+
+ atomic_set(&bb.done, 1);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+
+ blk_start_plug(&plug);
+ while (nr_sects) {
+ unsigned int req_sects;
+ sector_t end_sect, tmp;
+
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
+
+ /*
+ * If splitting a request, and the next starting sector would be
+ * misaligned, stop the discard at the previous aligned sector.
+ */
+ end_sect = sector + req_sects;
+ tmp = end_sect;
+ if (req_sects < nr_sects &&
+ sector_div(tmp, granularity) != alignment) {
+ end_sect = end_sect - alignment;
+ sector_div(end_sect, granularity);
+ end_sect = end_sect * granularity + alignment;
+ req_sects = end_sect - sector;
+ }
+
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_bdev = bdev;
+ bio->bi_private = &bb;
+
+ bio->bi_iter.bi_size = req_sects << 9;
+ nr_sects -= req_sects;
+ sector = end_sect;
+
+ atomic_inc(&bb.done);
+ submit_bio(type, bio);
+
+ /*
+ * We can loop for a long time in here, if someone does
+ * full device discards (like mkfs). Be nice and allow
+ * us to schedule out to avoid softlocking if preempt
+ * is disabled.
+ */
+ cond_resched();
+ }
+ blk_finish_plug(&plug);
+
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
+ wait_for_completion_io(&wait);
+
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ ret = -EIO;
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_discard);
+
+/**
+ * blkdev_issue_write_same - queue a write same operation
+ * @bdev: target blockdev
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @page: page containing data to write
+ *
+ * Description:
+ * Issue a write same request for the sectors in question.
+ */
+int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask,
+ struct page *page)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q = bdev_get_queue(bdev);
+ unsigned int max_write_same_sectors;
+ struct bio_batch bb;
+ struct bio *bio;
+ int ret = 0;
+
+ if (!q)
+ return -ENXIO;
+
+ max_write_same_sectors = q->limits.max_write_same_sectors;
+
+ if (max_write_same_sectors == 0)
+ return -EOPNOTSUPP;
+
+ atomic_set(&bb.done, 1);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+
+ while (nr_sects) {
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_bdev = bdev;
+ bio->bi_private = &bb;
+ bio->bi_vcnt = 1;
+ bio->bi_io_vec->bv_page = page;
+ bio->bi_io_vec->bv_offset = 0;
+ bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
+
+ if (nr_sects > max_write_same_sectors) {
+ bio->bi_iter.bi_size = max_write_same_sectors << 9;
+ nr_sects -= max_write_same_sectors;
+ sector += max_write_same_sectors;
+ } else {
+ bio->bi_iter.bi_size = nr_sects << 9;
+ nr_sects = 0;
+ }
+
+ atomic_inc(&bb.done);
+ submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
+ }
+
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
+ wait_for_completion_io(&wait);
+
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ ret = -ENOTSUPP;
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_write_same);
+
+/**
+ * blkdev_issue_zeroout - generate number of zero filed write bios
+ * @bdev: blockdev to issue
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ * Generate and issue number of bios with zerofiled pages.
+ */
+
+static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask)
+{
+ int ret;
+ struct bio *bio;
+ struct bio_batch bb;
+ unsigned int sz;
+ DECLARE_COMPLETION_ONSTACK(wait);
+
+ atomic_set(&bb.done, 1);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+
+ ret = 0;
+ while (nr_sects != 0) {
+ bio = bio_alloc(gfp_mask,
+ min(nr_sects, (sector_t)BIO_MAX_PAGES));
+ if (!bio) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_bdev = bdev;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_private = &bb;
+
+ while (nr_sects != 0) {
+ sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
+ ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
+ nr_sects -= ret >> 9;
+ sector += ret >> 9;
+ if (ret < (sz << 9))
+ break;
+ }
+ ret = 0;
+ atomic_inc(&bb.done);
+ submit_bio(WRITE, bio);
+ }
+
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
+ wait_for_completion_io(&wait);
+
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ /* One of bios in the batch was completed with error.*/
+ ret = -EIO;
+
+ return ret;
+}
+
+/**
+ * blkdev_issue_zeroout - zero-fill a block range
+ * @bdev: blockdev to write
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @discard: whether to discard the block range
+ *
+ * Description:
+ * Zero-fill a block range. If the discard flag is set and the block
+ * device guarantees that subsequent READ operations to the block range
+ * in question will return zeroes, the blocks will be discarded. Should
+ * the discard request fail, if the discard flag is not set, or if
+ * discard_zeroes_data is not supported, this function will resort to
+ * zeroing the blocks manually, thus provisioning (allocating,
+ * anchoring) them. If the block device supports the WRITE SAME command
+ * blkdev_issue_zeroout() will use it to optimize the process of
+ * clearing the block range. Otherwise the zeroing will be performed
+ * using regular WRITE calls.
+ */
+
+int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, bool discard)
+{
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
+ blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
+ return 0;
+
+ if (bdev_write_same(bdev) &&
+ blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+ ZERO_PAGE(0)) == 0)
+ return 0;
+
+ return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
+}
+EXPORT_SYMBOL(blkdev_issue_zeroout);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-11 15:54:52 +0000