dm mpath: remove unnecessary casts in front of ti->private

[cascardo/linux.git] / drivers / md / dm-mpath.c

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index cfa29f5..cfe5591 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -23,6 +23,7 @@
 #include <linux/delay.h>
 #include <scsi/scsi_dh.h>
 #include <linux/atomic.h>
+#include <linux/blk-mq.h>
 
 #define DM_MSG_PREFIX "multipath"
 #define DM_PG_INIT_DELAY_MSECS 2000
@@ -181,10 +182,9 @@ static void free_priority_group(struct priority_group *pg,
        kfree(pg);
 }
 
-static struct multipath *alloc_multipath(struct dm_target *ti)
+static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq)
 {
        struct multipath *m;
-       unsigned min_ios = dm_get_reserved_rq_based_ios();
 
        m = kzalloc(sizeof(*m), GFP_KERNEL);
        if (m) {
@@ -195,11 +195,18 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
                INIT_WORK(&m->trigger_event, trigger_event);
                init_waitqueue_head(&m->pg_init_wait);
                mutex_init(&m->work_mutex);
-               m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
-               if (!m->mpio_pool) {
-                       kfree(m);
-                       return NULL;
+
+               m->mpio_pool = NULL;
+               if (!use_blk_mq) {
+                       unsigned min_ios = dm_get_reserved_rq_based_ios();
+
+                       m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
+                       if (!m->mpio_pool) {
+                               kfree(m);
+                               return NULL;
+                       }
                }
+
                m->ti = ti;
                ti->private = m;
        }
@@ -222,26 +229,41 @@ static void free_multipath(struct multipath *m)
        kfree(m);
 }
 
-static int set_mapinfo(struct multipath *m, union map_info *info)
+static struct dm_mpath_io *get_mpio(union map_info *info)
+{
+       return info->ptr;
+}
+
+static struct dm_mpath_io *set_mpio(struct multipath *m, union map_info *info)
 {
        struct dm_mpath_io *mpio;
 
+       if (!m->mpio_pool) {
+               /* Use blk-mq pdu memory requested via per_io_data_size */
+               mpio = get_mpio(info);
+               memset(mpio, 0, sizeof(*mpio));
+               return mpio;
+       }
+
        mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
        if (!mpio)
-               return -ENOMEM;
+               return NULL;
 
        memset(mpio, 0, sizeof(*mpio));
        info->ptr = mpio;
 
-       return 0;
+       return mpio;
 }
 
-static void clear_mapinfo(struct multipath *m, union map_info *info)
+static void clear_request_fn_mpio(struct multipath *m, union map_info *info)
 {
-       struct dm_mpath_io *mpio = info->ptr;
+       /* Only needed for non blk-mq (.request_fn) multipath */
+       if (m->mpio_pool) {
+               struct dm_mpath_io *mpio = info->ptr;
 
-       info->ptr = NULL;
-       mempool_free(mpio, m->mpio_pool);
+               info->ptr = NULL;
+               mempool_free(mpio, m->mpio_pool);
+       }
 }
 
 /*-----------------------------------------------
@@ -380,7 +402,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
                           union map_info *map_context,
                           struct request *rq, struct request **__clone)
 {
-       struct multipath *m = (struct multipath *) ti->private;
+       struct multipath *m = ti->private;
        int r = DM_MAPIO_REQUEUE;
        size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq);
        struct pgpath *pgpath;
@@ -405,11 +427,11 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
                goto out_unlock;
        }
 
-       if (set_mapinfo(m, map_context) < 0)
+       mpio = set_mpio(m, map_context);
+       if (!mpio)
                /* ENOMEM, requeue */
                goto out_unlock;
 
-       mpio = map_context->ptr;
        mpio->pgpath = pgpath;
        mpio->nr_bytes = nr_bytes;
 
@@ -418,17 +440,24 @@ static int __multipath_map(struct dm_target *ti, struct request *clone,
        spin_unlock_irq(&m->lock);
 
        if (clone) {
-               /* Old request-based interface: allocated clone is passed in */
+               /*
+                * Old request-based interface: allocated clone is passed in.
+                * Used by: .request_fn stacked on .request_fn path(s).
+                */
                clone->q = bdev_get_queue(bdev);
                clone->rq_disk = bdev->bd_disk;
                clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
        } else {
-               /* blk-mq request-based interface */
-               *__clone = blk_get_request(bdev_get_queue(bdev),
-                                          rq_data_dir(rq), GFP_ATOMIC);
+               /*
+                * blk-mq request-based interface; used by both:
+                * .request_fn stacked on blk-mq path(s) and
+                * blk-mq stacked on blk-mq path(s).
+                */
+               *__clone = blk_mq_alloc_request(bdev_get_queue(bdev),
+                                               rq_data_dir(rq), BLK_MQ_REQ_NOWAIT);
                if (IS_ERR(*__clone)) {
                        /* ENOMEM, requeue */
-                       clear_mapinfo(m, map_context);
+                       clear_request_fn_mpio(m, map_context);
                        return r;
                }
                (*__clone)->bio = (*__clone)->biotail = NULL;
@@ -463,7 +492,7 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
 
 static void multipath_release_clone(struct request *clone)
 {
-       blk_put_request(clone);
+       blk_mq_free_request(clone);
 }
 
 /*
@@ -820,11 +849,12 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
        struct dm_arg_set as;
        unsigned pg_count = 0;
        unsigned next_pg_num;
+       bool use_blk_mq = dm_use_blk_mq(dm_table_get_md(ti->table));
 
        as.argc = argc;
        as.argv = argv;
 
-       m = alloc_multipath(ti);
+       m = alloc_multipath(ti, use_blk_mq);
        if (!m) {
                ti->error = "can't allocate multipath";
                return -EINVAL;
@@ -880,6 +910,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
        ti->num_flush_bios = 1;
        ti->num_discard_bios = 1;
        ti->num_write_same_bios = 1;
+       if (use_blk_mq)
+               ti->per_io_data_size = sizeof(struct dm_mpath_io);
 
        return 0;
 
@@ -1291,21 +1323,21 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
                            int error, union map_info *map_context)
 {
        struct multipath *m = ti->private;
-       struct dm_mpath_io *mpio = map_context->ptr;
+       struct dm_mpath_io *mpio = get_mpio(map_context);
        struct pgpath *pgpath;
        struct path_selector *ps;
        int r;
 
        BUG_ON(!mpio);
 
-       r  = do_end_io(m, clone, error, mpio);
+       r = do_end_io(m, clone, error, mpio);
        pgpath = mpio->pgpath;
        if (pgpath) {
                ps = &pgpath->pg->ps;
                if (ps->type->end_io)
                        ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
        }
-       clear_mapinfo(m, map_context);
+       clear_request_fn_mpio(m, map_context);
 
        return r;
 }
@@ -1318,7 +1350,7 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
  */
 static void multipath_presuspend(struct dm_target *ti)
 {
-       struct multipath *m = (struct multipath *) ti->private;
+       struct multipath *m = ti->private;
 
        queue_if_no_path(m, 0, 1);
 }
@@ -1337,7 +1369,7 @@ static void multipath_postsuspend(struct dm_target *ti)
  */
 static void multipath_resume(struct dm_target *ti)
 {
-       struct multipath *m = (struct multipath *) ti->private;
+       struct multipath *m = ti->private;
        unsigned long flags;
 
        spin_lock_irqsave(&m->lock, flags);
@@ -1366,7 +1398,7 @@ static void multipath_status(struct dm_target *ti, status_type_t type,
 {
        int sz = 0;
        unsigned long flags;
-       struct multipath *m = (struct multipath *) ti->private;
+       struct multipath *m = ti->private;
        struct priority_group *pg;
        struct pgpath *p;
        unsigned pg_num;
@@ -1474,7 +1506,7 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
 {
        int r = -EINVAL;
        struct dm_dev *dev;
-       struct multipath *m = (struct multipath *) ti->private;
+       struct multipath *m = ti->private;
        action_fn action;
 
        mutex_lock(&m->work_mutex);
@@ -1684,7 +1716,8 @@ out:
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
        .name = "multipath",
-       .version = {1, 10, 0},
+       .version = {1, 11, 0},
+       .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
        .module = THIS_MODULE,
        .ctr = multipath_ctr,
        .dtr = multipath_dtr,