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-rw-r--r--block/blk-lib.c345
1 files changed, 345 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
new file mode 100644
index 000000000..e59c3069e
--- /dev/null
+++ b/block/blk-lib.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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"
+
+static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
+{
+ unsigned int discard_granularity = bdev_discard_granularity(bdev);
+ sector_t granularity_aligned_sector;
+
+ if (bdev_is_partition(bdev))
+ sector += bdev->bd_start_sect;
+
+ granularity_aligned_sector =
+ round_up(sector, discard_granularity >> SECTOR_SHIFT);
+
+ /*
+ * Make sure subsequent bios start aligned to the discard granularity if
+ * it needs to be split.
+ */
+ if (granularity_aligned_sector != sector)
+ return granularity_aligned_sector - sector;
+
+ /*
+ * Align the bio size to the discard granularity to make splitting the bio
+ * at discard granularity boundaries easier in the driver if needed.
+ */
+ return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
+}
+
+int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
+{
+ struct bio *bio = *biop;
+ sector_t bs_mask;
+
+ if (bdev_read_only(bdev))
+ return -EPERM;
+ if (!bdev_max_discard_sectors(bdev))
+ return -EOPNOTSUPP;
+
+ /* In case the discard granularity isn't set by buggy device driver */
+ if (WARN_ON_ONCE(!bdev_discard_granularity(bdev))) {
+ pr_err_ratelimited("%pg: Error: discard_granularity is 0.\n",
+ bdev);
+ return -EOPNOTSUPP;
+ }
+
+ bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+ if ((sector | nr_sects) & bs_mask)
+ return -EINVAL;
+
+ if (!nr_sects)
+ return -EINVAL;
+
+ while (nr_sects) {
+ sector_t req_sects =
+ min(nr_sects, bio_discard_limit(bdev, sector));
+
+ bio = blk_next_bio(bio, bdev, 0, REQ_OP_DISCARD, gfp_mask);
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_iter.bi_size = req_sects << 9;
+ sector += req_sects;
+ nr_sects -= req_sects;
+
+ /*
+ * 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();
+ }
+
+ *biop = bio;
+ return 0;
+}
+EXPORT_SYMBOL(__blkdev_issue_discard);
+
+/**
+ * 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)
+ *
+ * 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)
+{
+ struct bio *bio = NULL;
+ struct blk_plug plug;
+ int ret;
+
+ blk_start_plug(&plug);
+ ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
+ if (!ret && bio) {
+ ret = submit_bio_wait(bio);
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ bio_put(bio);
+ }
+ blk_finish_plug(&plug);
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_discard);
+
+static int __blkdev_issue_write_zeroes(struct block_device *bdev,
+ sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
+ struct bio **biop, unsigned flags)
+{
+ struct bio *bio = *biop;
+ unsigned int max_write_zeroes_sectors;
+
+ if (bdev_read_only(bdev))
+ return -EPERM;
+
+ /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
+ max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
+
+ if (max_write_zeroes_sectors == 0)
+ return -EOPNOTSUPP;
+
+ while (nr_sects) {
+ bio = blk_next_bio(bio, bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
+ bio->bi_iter.bi_sector = sector;
+ if (flags & BLKDEV_ZERO_NOUNMAP)
+ bio->bi_opf |= REQ_NOUNMAP;
+
+ if (nr_sects > max_write_zeroes_sectors) {
+ bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
+ nr_sects -= max_write_zeroes_sectors;
+ sector += max_write_zeroes_sectors;
+ } else {
+ bio->bi_iter.bi_size = nr_sects << 9;
+ nr_sects = 0;
+ }
+ cond_resched();
+ }
+
+ *biop = bio;
+ return 0;
+}
+
+/*
+ * Convert a number of 512B sectors to a number of pages.
+ * The result is limited to a number of pages that can fit into a BIO.
+ * Also make sure that the result is always at least 1 (page) for the cases
+ * where nr_sects is lower than the number of sectors in a page.
+ */
+static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
+{
+ sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
+
+ return min(pages, (sector_t)BIO_MAX_VECS);
+}
+
+static int __blkdev_issue_zero_pages(struct block_device *bdev,
+ sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
+ struct bio **biop)
+{
+ struct bio *bio = *biop;
+ int bi_size = 0;
+ unsigned int sz;
+
+ if (bdev_read_only(bdev))
+ return -EPERM;
+
+ while (nr_sects != 0) {
+ bio = blk_next_bio(bio, bdev, __blkdev_sectors_to_bio_pages(nr_sects),
+ REQ_OP_WRITE, gfp_mask);
+ bio->bi_iter.bi_sector = sector;
+
+ while (nr_sects != 0) {
+ sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
+ bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
+ nr_sects -= bi_size >> 9;
+ sector += bi_size >> 9;
+ if (bi_size < sz)
+ break;
+ }
+ cond_resched();
+ }
+
+ *biop = bio;
+ return 0;
+}
+
+/**
+ * __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)
+ * @biop: pointer to anchor bio
+ * @flags: controls detailed behavior
+ *
+ * Description:
+ * Zero-fill a block range, either using hardware offload or by explicitly
+ * writing zeroes to the device.
+ *
+ * If a device is using logical block provisioning, the underlying space will
+ * not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
+ *
+ * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
+ * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
+ */
+int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
+ unsigned flags)
+{
+ int ret;
+ sector_t bs_mask;
+
+ bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+ if ((sector | nr_sects) & bs_mask)
+ return -EINVAL;
+
+ ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
+ biop, flags);
+ if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
+ return ret;
+
+ return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
+ biop);
+}
+EXPORT_SYMBOL(__blkdev_issue_zeroout);
+
+/**
+ * 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)
+ * @flags: controls detailed behavior
+ *
+ * Description:
+ * Zero-fill a block range, either using hardware offload or by explicitly
+ * writing zeroes to the device. See __blkdev_issue_zeroout() for the
+ * valid values for %flags.
+ */
+int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
+{
+ int ret = 0;
+ sector_t bs_mask;
+ struct bio *bio;
+ struct blk_plug plug;
+ bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
+
+ bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+ if ((sector | nr_sects) & bs_mask)
+ return -EINVAL;
+
+retry:
+ bio = NULL;
+ blk_start_plug(&plug);
+ if (try_write_zeroes) {
+ ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
+ gfp_mask, &bio, flags);
+ } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
+ ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
+ gfp_mask, &bio);
+ } else {
+ /* No zeroing offload support */
+ ret = -EOPNOTSUPP;
+ }
+ if (ret == 0 && bio) {
+ ret = submit_bio_wait(bio);
+ bio_put(bio);
+ }
+ blk_finish_plug(&plug);
+ if (ret && try_write_zeroes) {
+ if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
+ try_write_zeroes = false;
+ goto retry;
+ }
+ if (!bdev_write_zeroes_sectors(bdev)) {
+ /*
+ * Zeroing offload support was indicated, but the
+ * device reported ILLEGAL REQUEST (for some devices
+ * there is no non-destructive way to verify whether
+ * WRITE ZEROES is actually supported).
+ */
+ ret = -EOPNOTSUPP;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_zeroout);
+
+int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp)
+{
+ sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
+ unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
+ struct bio *bio = NULL;
+ struct blk_plug plug;
+ int ret = 0;
+
+ /* make sure that "len << SECTOR_SHIFT" doesn't overflow */
+ if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
+ max_sectors = UINT_MAX >> SECTOR_SHIFT;
+ max_sectors &= ~bs_mask;
+
+ if (max_sectors == 0)
+ return -EOPNOTSUPP;
+ if ((sector | nr_sects) & bs_mask)
+ return -EINVAL;
+ if (bdev_read_only(bdev))
+ return -EPERM;
+
+ blk_start_plug(&plug);
+ for (;;) {
+ unsigned int len = min_t(sector_t, nr_sects, max_sectors);
+
+ bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
+ bio->bi_iter.bi_sector = sector;
+ bio->bi_iter.bi_size = len << SECTOR_SHIFT;
+
+ sector += len;
+ nr_sects -= len;
+ if (!nr_sects) {
+ ret = submit_bio_wait(bio);
+ bio_put(bio);
+ break;
+ }
+ cond_resched();
+ }
+ blk_finish_plug(&plug);
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_secure_erase);