bcache: drop discard sysfs interface

Since discard code is removed, now the sysfs interface to enable discard
is useless. This patch removes the corresponding sysfs entry, and remove
bool variable 'discard' from struct cache as well.

Signed-off-by: Coly Li <colyli@fnnas.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 1d33e40..b8bd6d4 100644 (file)
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -447,8 +447,7 @@ struct cache {
         * free_inc: Incoming buckets - these are buckets that currently have
         * cached data in them, and we can't reuse them until after we write
         * their new gen to disk. After prio_write() finishes writing the new
-        * gens/prios, they'll be moved to the free list (and possibly discarded
-        * in the process)
+        * gens/prios, they'll be moved to the free list.
         */
        DECLARE_FIFO(long, free)[RESERVE_NR];
        DECLARE_FIFO(long, free_inc);
@@ -467,8 +466,6 @@ struct cache {
         */
        unsigned int            invalidate_needs_gc;
 
-       bool                    discard; /* Get rid of? */
-
        struct journal_device   journal;
 
        /* The rest of this all shows up in sysfs */

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 6d250e3..91a98eb 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2382,9 +2382,6 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
        ca->bdev = file_bdev(bdev_file);
        ca->sb_disk = sb_disk;
 
-       if (bdev_max_discard_sectors(file_bdev(bdev_file)))
-               ca->discard = CACHE_DISCARD(&ca->sb);
-
        ret = cache_alloc(ca);
        if (ret != 0) {
                if (ret == -ENOMEM)

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 826b14c..72f38e5 100644 (file)
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -134,7 +134,6 @@ read_attribute(partial_stripes_expensive);
 rw_attribute(synchronous);
 rw_attribute(journal_delay_ms);
 rw_attribute(io_disable);
-rw_attribute(discard);
 rw_attribute(running);
 rw_attribute(label);
 rw_attribute(errors);
@@ -1036,7 +1035,6 @@ SHOW(__bch_cache)
        sysfs_hprint(bucket_size,       bucket_bytes(ca));
        sysfs_hprint(block_size,        block_bytes(ca));
        sysfs_print(nbuckets,           ca->sb.nbuckets);
-       sysfs_print(discard,            ca->discard);
        sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
        sysfs_hprint(btree_written,
                     atomic_long_read(&ca->btree_sectors_written) << 9);
@@ -1142,18 +1140,6 @@ STORE(__bch_cache)
        if (bcache_is_reboot)
                return -EBUSY;
 
-       if (attr == &sysfs_discard) {
-               bool v = strtoul_or_return(buf);
-
-               if (bdev_max_discard_sectors(ca->bdev))
-                       ca->discard = v;
-
-               if (v != CACHE_DISCARD(&ca->sb)) {
-                       SET_CACHE_DISCARD(&ca->sb, v);
-                       bcache_write_super(ca->set);
-               }
-       }
-
        if (attr == &sysfs_cache_replacement_policy) {
                v = __sysfs_match_string(cache_replacement_policies, -1, buf);
                if (v < 0)
@@ -1185,7 +1171,6 @@ static struct attribute *bch_cache_attrs[] = {
        &sysfs_block_size,
        &sysfs_nbuckets,
        &sysfs_priority_stats,
-       &sysfs_discard,
        &sysfs_written,
        &sysfs_btree_written,
        &sysfs_metadata_written,

diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 6ba73dc..cffef33 100644 (file)
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -805,8 +805,7 @@ static int bch_writeback_thread(void *arg)
                         * may set BCH_ENABLE_AUTO_GC via sysfs, then when
                         * BCH_DO_AUTO_GC is set, garbage collection thread
                         * will be wake up here. After moving gc, the shrunk
-                        * btree and discarded free buckets SSD space may be
-                        * helpful for following write requests.
+                        * btree may be helpful for following write requests.
                         */
                        if (c->gc_after_writeback ==
                            (BCH_ENABLE_AUTO_GC|BCH_DO_AUTO_GC)) {