block: add a report_zones method
Dispatching a report zones command through the request queue is a major
pain due to the command reply payload rewriting necessary. Given that
blkdev_report_zones() is executing everything synchronously, implement
report zones as a block device file operation instead, allowing major
simplification of the code in many places.
sd, null-blk, dm-linear and dm-flakey being the only block device
drivers supporting exposing zoned block devices, these drivers are
modified to provide the device side implementation of the
report_zones() block device file operation.
For device mappers, a new report_zones() target type operation is
defined so that the upper block layer calls blkdev_report_zones() can
be propagated down to the underlying devices of the dm targets.
Implementation for this new operation is added to the dm-linear and
dm-flakey targets.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[Damien]
* Changed method block_device argument to gendisk
* Various bug fixes and improvements
* Added support for null_blk, dm-linear and dm-flakey.
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 5d967fd..90cf503 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -93,13 +93,10 @@ unsigned int blkdev_nr_zones(struct block_device *bdev)
EXPORT_SYMBOL_GPL(blkdev_nr_zones);
/*
- * Check that a zone report belongs to the partition.
- * If yes, fix its start sector and write pointer, copy it in the
- * zone information array and return true. Return false otherwise.
+ * Check that a zone report belongs to this partition, and if yes, fix its start
+ * sector and write pointer and return true. Return false otherwise.
*/
-static bool blkdev_report_zone(struct block_device *bdev,
- struct blk_zone *rep,
- struct blk_zone *zone)
+static bool blkdev_report_zone(struct block_device *bdev, struct blk_zone *rep)
{
sector_t offset = get_start_sect(bdev);
@@ -114,11 +111,36 @@ static bool blkdev_report_zone(struct block_device *bdev,
rep->wp = rep->start + rep->len;
else
rep->wp -= offset;
- memcpy(zone, rep, sizeof(struct blk_zone));
-
return true;
}
+static int blk_report_zones(struct gendisk *disk, sector_t sector,
+ struct blk_zone *zones, unsigned int *nr_zones,
+ gfp_t gfp_mask)
+{
+ struct request_queue *q = disk->queue;
+ unsigned int z = 0, n, nrz = *nr_zones;
+ sector_t capacity = get_capacity(disk);
+ int ret;
+
+ while (z < nrz && sector < capacity) {
+ n = nrz - z;
+ ret = disk->fops->report_zones(disk, sector, &zones[z], &n,
+ gfp_mask);
+ if (ret)
+ return ret;
+ if (!n)
+ break;
+ sector += blk_queue_zone_sectors(q) * n;
+ z += n;
+ }
+
+ WARN_ON(z > *nr_zones);
+ *nr_zones = z;
+
+ return 0;
+}
+
/**
* blkdev_report_zones - Get zones information
* @bdev: Target block device
@@ -133,130 +155,46 @@ static bool blkdev_report_zone(struct block_device *bdev,
* requested by @nr_zones. The number of zones actually reported is
* returned in @nr_zones.
*/
-int blkdev_report_zones(struct block_device *bdev,
- sector_t sector,
- struct blk_zone *zones,
- unsigned int *nr_zones,
+int blkdev_report_zones(struct block_device *bdev, sector_t sector,
+ struct blk_zone *zones, unsigned int *nr_zones,
gfp_t gfp_mask)
{
struct request_queue *q = bdev_get_queue(bdev);
- struct blk_zone_report_hdr *hdr;
- unsigned int nrz = *nr_zones;
- struct page *page;
- unsigned int nr_rep;
- size_t rep_bytes;
- unsigned int nr_pages;
- struct bio *bio;
- struct bio_vec *bv;
- unsigned int i, n, nz;
- unsigned int ofst;
- void *addr;
+ unsigned int i, nrz;
int ret;
- if (!q)
- return -ENXIO;
-
if (!blk_queue_is_zoned(q))
return -EOPNOTSUPP;
- if (!nrz)
- return 0;
+ /*
+ * A block device that advertized itself as zoned must have a
+ * report_zones method. If it does not have one defined, the device
+ * driver has a bug. So warn about that.
+ */
+ if (WARN_ON_ONCE(!bdev->bd_disk->fops->report_zones))
+ return -EOPNOTSUPP;
- if (sector > bdev->bd_part->nr_sects) {
+ if (!*nr_zones || sector >= bdev->bd_part->nr_sects) {
*nr_zones = 0;
return 0;
}
- /*
- * The zone report has a header. So make room for it in the
- * payload. Also make sure that the report fits in a single BIO
- * that will not be split down the stack.
- */
- rep_bytes = sizeof(struct blk_zone_report_hdr) +
- sizeof(struct blk_zone) * nrz;
- rep_bytes = (rep_bytes + PAGE_SIZE - 1) & PAGE_MASK;
- if (rep_bytes > (queue_max_sectors(q) << 9))
- rep_bytes = queue_max_sectors(q) << 9;
-
- nr_pages = min_t(unsigned int, BIO_MAX_PAGES,
- rep_bytes >> PAGE_SHIFT);
- nr_pages = min_t(unsigned int, nr_pages,
- queue_max_segments(q));
-
- bio = bio_alloc(gfp_mask, nr_pages);
- if (!bio)
- return -ENOMEM;
-
- bio_set_dev(bio, bdev);
- bio->bi_iter.bi_sector = blk_zone_start(q, sector);
- bio_set_op_attrs(bio, REQ_OP_ZONE_REPORT, 0);
-
- for (i = 0; i < nr_pages; i++) {
- page = alloc_page(gfp_mask);
- if (!page) {
- ret = -ENOMEM;
- goto out;
- }
- if (!bio_add_page(bio, page, PAGE_SIZE, 0)) {
- __free_page(page);
- break;
- }
- }
-
- if (i == 0)
- ret = -ENOMEM;
- else
- ret = submit_bio_wait(bio);
+ nrz = min(*nr_zones,
+ __blkdev_nr_zones(q, bdev->bd_part->nr_sects - sector));
+ ret = blk_report_zones(bdev->bd_disk, get_start_sect(bdev) + sector,
+ zones, &nrz, gfp_mask);
if (ret)
- goto out;
+ return ret;
- /*
- * Process the report result: skip the header and go through the
- * reported zones to fixup and fixup the zone information for
- * partitions. At the same time, return the zone information into
- * the zone array.
- */
- n = 0;
- nz = 0;
- nr_rep = 0;
- bio_for_each_segment_all(bv, bio, i) {
-
- if (!bv->bv_page)
+ for (i = 0; i < nrz; i++) {
+ if (!blkdev_report_zone(bdev, zones))
break;
-
- addr = kmap_atomic(bv->bv_page);
-
- /* Get header in the first page */
- ofst = 0;
- if (!nr_rep) {
- hdr = addr;
- nr_rep = hdr->nr_zones;
- ofst = sizeof(struct blk_zone_report_hdr);
- }
-
- /* Fixup and report zones */
- while (ofst < bv->bv_len &&
- n < nr_rep && nz < nrz) {
- if (blkdev_report_zone(bdev, addr + ofst, &zones[nz]))
- nz++;
- ofst += sizeof(struct blk_zone);
- n++;
- }
-
- kunmap_atomic(addr);
-
- if (n >= nr_rep || nz >= nrz)
- break;
-
+ zones++;
}
- *nr_zones = nz;
-out:
- bio_for_each_segment_all(bv, bio, i)
- __free_page(bv->bv_page);
- bio_put(bio);
+ *nr_zones = i;
- return ret;
+ return 0;
}
EXPORT_SYMBOL_GPL(blkdev_report_zones);