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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-12 22:33:29 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-12 22:33:29 +0200
commit0e04c641b199435f3779454055f6a7de258ecdfc (patch)
tree9b79da0c52240bf4b96270ac12356ad75da6f739 /drivers/md/dm.c
parentMerge tag 'pci-v3.16-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/... (diff)
parentdm thin: update discard_granularity to reflect the thin-pool blocksize (diff)
downloadlinux-0e04c641b199435f3779454055f6a7de258ecdfc.tar.xz
linux-0e04c641b199435f3779454055f6a7de258ecdfc.zip
Merge tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer: "This pull request is later than I'd have liked because I was waiting for some performance data to help finally justify sending the long-standing dm-crypt cpu scalability improvements upstream. Unfortunately we came up short, so those dm-crypt changes will continue to wait, but it seems we're not far off. . Add dm_accept_partial_bio interface to DM core to allow DM targets to only process a portion of a bio, the remainder being sent in the next bio. This enables the old dm snapshot-origin target to only split write bios on chunk boundaries, read bios are now sent to the origin device unchanged. . Add DM core support for disabling WRITE SAME if the underlying SCSI layer disables it due to command failure. . Reduce lock contention in DM's bio-prison. . A few small cleanups and fixes to dm-thin and dm-era" * tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm thin: update discard_granularity to reflect the thin-pool blocksize dm bio prison: implement per bucket locking in the dm_bio_prison hash table dm: remove symbol export for dm_set_device_limits dm: disable WRITE SAME if it fails dm era: check for a non-NULL metadata object before closing it dm thin: return ENOSPC instead of EIO when error_if_no_space enabled dm thin: cleanup noflush_work to use a proper completion dm snapshot: do not split read bios sent to snapshot-origin target dm snapshot: allocate a per-target structure for snapshot-origin target dm: introduce dm_accept_partial_bio dm: change sector_count member in clone_info from sector_t to unsigned
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c86
1 files changed, 72 insertions, 14 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index aa9e093343d4..437d99045ef2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -755,6 +755,14 @@ static void dec_pending(struct dm_io *io, int error)
}
}
+static void disable_write_same(struct mapped_device *md)
+{
+ struct queue_limits *limits = dm_get_queue_limits(md);
+
+ /* device doesn't really support WRITE SAME, disable it */
+ limits->max_write_same_sectors = 0;
+}
+
static void clone_endio(struct bio *bio, int error)
{
int r = 0;
@@ -783,6 +791,10 @@ static void clone_endio(struct bio *bio, int error)
}
}
+ if (unlikely(r == -EREMOTEIO && (bio->bi_rw & REQ_WRITE_SAME) &&
+ !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors))
+ disable_write_same(md);
+
free_tio(md, tio);
dec_pending(io, error);
}
@@ -977,6 +989,10 @@ static void dm_done(struct request *clone, int error, bool mapped)
r = rq_end_io(tio->ti, clone, error, &tio->info);
}
+ if (unlikely(r == -EREMOTEIO && (clone->cmd_flags & REQ_WRITE_SAME) &&
+ !clone->q->limits.max_write_same_sectors))
+ disable_write_same(tio->md);
+
if (r <= 0)
/* The target wants to complete the I/O */
dm_end_request(clone, r);
@@ -1110,6 +1126,46 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
+/*
+ * A target may call dm_accept_partial_bio only from the map routine. It is
+ * allowed for all bio types except REQ_FLUSH.
+ *
+ * dm_accept_partial_bio informs the dm that the target only wants to process
+ * additional n_sectors sectors of the bio and the rest of the data should be
+ * sent in a next bio.
+ *
+ * A diagram that explains the arithmetics:
+ * +--------------------+---------------+-------+
+ * | 1 | 2 | 3 |
+ * +--------------------+---------------+-------+
+ *
+ * <-------------- *tio->len_ptr --------------->
+ * <------- bi_size ------->
+ * <-- n_sectors -->
+ *
+ * Region 1 was already iterated over with bio_advance or similar function.
+ * (it may be empty if the target doesn't use bio_advance)
+ * Region 2 is the remaining bio size that the target wants to process.
+ * (it may be empty if region 1 is non-empty, although there is no reason
+ * to make it empty)
+ * The target requires that region 3 is to be sent in the next bio.
+ *
+ * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
+ * the partially processed part (the sum of regions 1+2) must be the same for all
+ * copies of the bio.
+ */
+void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
+{
+ struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
+ unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
+ BUG_ON(bio->bi_rw & REQ_FLUSH);
+ BUG_ON(bi_size > *tio->len_ptr);
+ BUG_ON(n_sectors > bi_size);
+ *tio->len_ptr -= bi_size - n_sectors;
+ bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
+}
+EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
+
static void __map_bio(struct dm_target_io *tio)
{
int r;
@@ -1152,10 +1208,10 @@ struct clone_info {
struct bio *bio;
struct dm_io *io;
sector_t sector;
- sector_t sector_count;
+ unsigned sector_count;
};
-static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
+static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
{
bio->bi_iter.bi_sector = sector;
bio->bi_iter.bi_size = to_bytes(len);
@@ -1200,11 +1256,13 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
static void __clone_and_map_simple_bio(struct clone_info *ci,
struct dm_target *ti,
- unsigned target_bio_nr, sector_t len)
+ unsigned target_bio_nr, unsigned *len)
{
struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
struct bio *clone = &tio->clone;
+ tio->len_ptr = len;
+
/*
* Discard requests require the bio's inline iovecs be initialized.
* ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
@@ -1212,13 +1270,13 @@ static void __clone_and_map_simple_bio(struct clone_info *ci,
*/
__bio_clone_fast(clone, ci->bio);
if (len)
- bio_setup_sector(clone, ci->sector, len);
+ bio_setup_sector(clone, ci->sector, *len);
__map_bio(tio);
}
static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
- unsigned num_bios, sector_t len)
+ unsigned num_bios, unsigned *len)
{
unsigned target_bio_nr;
@@ -1233,13 +1291,13 @@ static int __send_empty_flush(struct clone_info *ci)
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
- __send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
+ __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
return 0;
}
static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
- sector_t sector, unsigned len)
+ sector_t sector, unsigned *len)
{
struct bio *bio = ci->bio;
struct dm_target_io *tio;
@@ -1254,7 +1312,8 @@ static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti
for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
tio = alloc_tio(ci, ti, 0, target_bio_nr);
- clone_bio(tio, bio, sector, len);
+ tio->len_ptr = len;
+ clone_bio(tio, bio, sector, *len);
__map_bio(tio);
}
}
@@ -1283,7 +1342,7 @@ static int __send_changing_extent_only(struct clone_info *ci,
is_split_required_fn is_split_required)
{
struct dm_target *ti;
- sector_t len;
+ unsigned len;
unsigned num_bios;
do {
@@ -1302,11 +1361,11 @@ static int __send_changing_extent_only(struct clone_info *ci,
return -EOPNOTSUPP;
if (is_split_required && !is_split_required(ti))
- len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+ len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
else
- len = min(ci->sector_count, max_io_len(ci->sector, ti));
+ len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti));
- __send_duplicate_bios(ci, ti, num_bios, len);
+ __send_duplicate_bios(ci, ti, num_bios, &len);
ci->sector += len;
} while (ci->sector_count -= len);
@@ -1345,7 +1404,7 @@ static int __split_and_process_non_flush(struct clone_info *ci)
len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
- __clone_and_map_data_bio(ci, ti, ci->sector, len);
+ __clone_and_map_data_bio(ci, ti, ci->sector, &len);
ci->sector += len;
ci->sector_count -= len;
@@ -1439,7 +1498,6 @@ static int dm_merge_bvec(struct request_queue *q,
* just one page.
*/
else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
-
max_size = 0;
out: