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authorMikulas Patocka <mpatocka@redhat.com>2019-10-02 06:14:17 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-06 12:42:51 +0100
commitcd83f10afd9d7c0e37b46b8d0c261a31499db210 (patch)
tree405502840439bf936e9abe1979dcb9677612ed52 /drivers/md
parentf62931ec9ded76f0f16359d7b58dbb271326b4ac (diff)
dm snapshot: introduce account_start_copy() and account_end_copy()
[ Upstream commit a2f83e8b0c82c9500421a26c49eb198b25fcdea3 ] This simple refactoring moves code for modifying the semaphore cow_count into separate functions to prepare for changes that will extend these methods to provide for a more sophisticated mechanism for COW throttling. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Nikos Tsironis <ntsironis@arrikto.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-snap.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 8b1556e77a0a..a9575122a0c6 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1399,6 +1399,16 @@ static void snapshot_dtr(struct dm_target *ti)
kfree(s);
}
+static void account_start_copy(struct dm_snapshot *s)
+{
+ down(&s->cow_count);
+}
+
+static void account_end_copy(struct dm_snapshot *s)
+{
+ up(&s->cow_count);
+}
+
/*
* Flush a list of buffers.
*/
@@ -1581,7 +1591,7 @@ static void copy_callback(int read_err, unsigned long write_err, void *context)
}
list_add(&pe->out_of_order_entry, lh);
}
- up(&s->cow_count);
+ account_end_copy(s);
}
/*
@@ -1605,7 +1615,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
dest.count = src.count;
/* Hand over to kcopyd */
- down(&s->cow_count);
+ account_start_copy(s);
dm_kcopyd_copy(s->kcopyd_client, &src, 1, &dest, 0, copy_callback, pe);
}
@@ -1625,7 +1635,7 @@ static void start_full_bio(struct dm_snap_pending_exception *pe,
pe->full_bio = bio;
pe->full_bio_end_io = bio->bi_end_io;
- down(&s->cow_count);
+ account_start_copy(s);
callback_data = dm_kcopyd_prepare_callback(s->kcopyd_client,
copy_callback, pe);