bcache: Kill unaligned bvec hack

Bcache has a hack to avoid cloning the biovec if it's all full pages -
but with immutable biovecs coming this won't be necessary anymore.

For now, we remove the special case and always clone the bvec array so
that the immutable biovec patches are simpler.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

3 files changed, 7 insertions, 35 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 4beb55a0ff30..6b6fe935be73 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -279,7 +279,6 @@ struct bcache_device {
         unsigned long           sectors_dirty_last;
         long                    sectors_dirty_derivative;
 
-        mempool_t               *unaligned_bvec;
         struct bio_set          *bio_split;
 
         unsigned                data_csum:1;
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index fbcc851ed5a5..78bab4154e97 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -606,7 +606,6 @@ struct search {
         unsigned                insert_bio_sectors;
 
         unsigned                recoverable:1;
-        unsigned                unaligned_bvec:1;
         unsigned                write:1;
         unsigned                read_dirty_data:1;
 
@@ -614,6 +613,7 @@ struct search {
 
         struct btree_op         op;
         struct data_insert_op   iop;
+        struct bio_vec          bv[BIO_MAX_PAGES];
 };
 
 static void bch_cache_read_endio(struct bio *bio, int error)
@@ -759,10 +759,14 @@ static void bio_complete(struct search *s)
 static void do_bio_hook(struct search *s)
 {
         struct bio *bio = &s->bio.bio;
-        memcpy(bio, s->orig_bio, sizeof(struct bio));
 
+        bio_init(bio);
+        bio->bi_io_vec          = s->bv;
+        bio->bi_max_vecs        = BIO_MAX_PAGES;
+        __bio_clone(bio, s->orig_bio);
         bio->bi_end_io          = request_endio;
         bio->bi_private         = &s->cl;
+
         atomic_set(&bio->bi_cnt, 3);
 }
 
@@ -774,9 +778,6 @@ static void search_free(struct closure *cl)
         if (s->iop.bio)
                 bio_put(s->iop.bio);
 
-        if (s->unaligned_bvec)
-                mempool_free(s->bio.bio.bi_io_vec, s->d->unaligned_bvec);
-
         closure_debug_destroy(cl);
         mempool_free(s, s->d->c->search);
 }
@@ -784,7 +785,6 @@ static void search_free(struct closure *cl)
 static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
 {
         struct search *s;
-        struct bio_vec *bv;
 
         s = mempool_alloc(d->c->search, GFP_NOIO);
         memset(s, 0, offsetof(struct search, iop.insert_keys));
@@ -803,15 +803,6 @@ static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
         s->start_time           = jiffies;
         do_bio_hook(s);
 
-        if (bio->bi_size != bio_segments(bio) * PAGE_SIZE) {
-                bv = mempool_alloc(d->unaligned_bvec, GFP_NOIO);
-                memcpy(bv, bio_iovec(bio),
-                       sizeof(struct bio_vec) * bio_segments(bio));
-
-                s->bio.bio.bi_io_vec    = bv;
-                s->unaligned_bvec       = 1;
-        }
-
         return s;
 }
 
@@ -850,26 +841,13 @@ static void cached_dev_read_error(struct closure *cl)
 {
         struct search *s = container_of(cl, struct search, cl);
         struct bio *bio = &s->bio.bio;
-        struct bio_vec *bv;
-        int i;
 
         if (s->recoverable) {
                 /* Retry from the backing device: */
                 trace_bcache_read_retry(s->orig_bio);
 
                 s->iop.error = 0;
-                bv = s->bio.bio.bi_io_vec;
                 do_bio_hook(s);
-                s->bio.bio.bi_io_vec = bv;
-
-                if (!s->unaligned_bvec)
-                        bio_for_each_segment(bv, s->orig_bio, i)
-                                bv->bv_offset = 0, bv->bv_len = PAGE_SIZE;
-                else
-                        memcpy(s->bio.bio.bi_io_vec,
-                               bio_iovec(s->orig_bio),
-                               sizeof(struct bio_vec) *
-                               bio_segments(s->orig_bio));
 
                 /* XXX: invalidate cache */
 
@@ -905,8 +883,7 @@ static void cached_dev_read_done(struct closure *cl)
                 s->cache_miss = NULL;
         }
 
-        if (verify(dc, &s->bio.bio) && s->recoverable &&
-            !s->unaligned_bvec && !s->read_dirty_data)
+        if (verify(dc, &s->bio.bio) && s->recoverable && !s->read_dirty_data)
                 bch_data_verify(dc, s->orig_bio);
 
         bio_complete(s);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index dec15cd2d797..1d9ee67d14ec 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -739,8 +739,6 @@ static void bcache_device_free(struct bcache_device *d)
         }
 
         bio_split_pool_free(&d->bio_split_hook);
-        if (d->unaligned_bvec)
-                mempool_destroy(d->unaligned_bvec);
         if (d->bio_split)
                 bioset_free(d->bio_split);
         if (is_vmalloc_addr(d->full_dirty_stripes))
@@ -793,8 +791,6 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
                 return minor;
 
         if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
-            !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
-                                sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
             bio_split_pool_init(&d->bio_split_hook) ||
             !(d->disk = alloc_disk(1))) {
                 ida_simple_remove(&bcache_minor, minor);