diff options
| -rw-r--r-- | drivers/block/loop.c | 233 |
1 files changed, 39 insertions, 194 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index dd049764bb0c..ebe751f39742 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -68,7 +68,6 @@ struct loop_device { struct rb_root worker_tree; struct timer_list timer; bool sysfs_inited; - unsigned lo_nr_blocking_writes; struct request_queue *lo_queue; struct blk_mq_tag_set tag_set; @@ -91,8 +90,6 @@ struct loop_cmd { #define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ) #define LOOP_DEFAULT_HW_Q_DEPTH 128 -static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd); - static DEFINE_IDR(loop_index_idr); static DEFINE_MUTEX(loop_ctl_mutex); static DEFINE_MUTEX(loop_validate_mutex); @@ -324,15 +321,6 @@ static void lo_rw_aio_do_completion(struct loop_cmd *cmd) if (!atomic_dec_and_test(&cmd->ref)) return; - - /* -EAGAIN could be returned from bdev's ->ki_complete */ - if (cmd->ret == -EAGAIN) { - struct loop_device *lo = rq->q->queuedata; - - loop_queue_work(lo, cmd); - return; - } - kfree(cmd->bvec); cmd->bvec = NULL; if (req_op(rq) == REQ_OP_WRITE) @@ -349,28 +337,24 @@ static void lo_rw_aio_complete(struct kiocb *iocb, long ret) lo_rw_aio_do_completion(cmd); } -static inline unsigned lo_cmd_nr_bvec(struct loop_cmd *cmd) +static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, + loff_t pos, int rw) { - struct request *rq = blk_mq_rq_from_pdu(cmd); + struct iov_iter iter; struct req_iterator rq_iter; + struct bio_vec *bvec; + struct request *rq = blk_mq_rq_from_pdu(cmd); + struct bio *bio = rq->bio; + struct file *file = lo->lo_backing_file; struct bio_vec tmp; + unsigned int offset; int nr_bvec = 0; + int ret; rq_for_each_bvec(tmp, rq, rq_iter) nr_bvec++; - return nr_bvec; -} - -static int lo_rw_aio_prep(struct loop_device *lo, struct loop_cmd *cmd, - unsigned nr_bvec, loff_t pos) -{ - struct request *rq = blk_mq_rq_from_pdu(cmd); - if (rq->bio != rq->biotail) { - struct req_iterator rq_iter; - struct bio_vec *bvec; - struct bio_vec tmp; bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), GFP_NOIO); @@ -388,12 +372,24 @@ static int lo_rw_aio_prep(struct loop_device *lo, struct loop_cmd *cmd, *bvec = tmp; bvec++; } + bvec = cmd->bvec; + offset = 0; } else { - cmd->bvec = NULL; + /* + * Same here, this bio may be started from the middle of the + * 'bvec' because of bio splitting, so offset from the bvec + * must be passed to iov iterator + */ + offset = bio->bi_iter.bi_bvec_done; + bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); } + atomic_set(&cmd->ref, 2); + + iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); + iter.iov_offset = offset; cmd->iocb.ki_pos = pos; - cmd->iocb.ki_filp = lo->lo_backing_file; + cmd->iocb.ki_filp = file; cmd->iocb.ki_ioprio = req_get_ioprio(rq); if (cmd->use_aio) { cmd->iocb.ki_complete = lo_rw_aio_complete; @@ -402,35 +398,6 @@ static int lo_rw_aio_prep(struct loop_device *lo, struct loop_cmd *cmd, cmd->iocb.ki_complete = NULL; cmd->iocb.ki_flags = 0; } - return 0; -} - -static int lo_submit_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, - int nr_bvec, int rw) -{ - struct request *rq = blk_mq_rq_from_pdu(cmd); - struct file *file = lo->lo_backing_file; - struct iov_iter iter; - int ret; - - if (cmd->bvec) { - iov_iter_bvec(&iter, rw, cmd->bvec, nr_bvec, blk_rq_bytes(rq)); - iter.iov_offset = 0; - } else { - struct bio *bio = rq->bio; - struct bio_vec *bvec = __bvec_iter_bvec(bio->bi_io_vec, - bio->bi_iter); - - /* - * Same here, this bio may be started from the middle of the - * 'bvec' because of bio splitting, so offset from the bvec - * must be passed to iov iterator - */ - iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); - iter.iov_offset = bio->bi_iter.bi_bvec_done; - } - atomic_set(&cmd->ref, 2); - if (rw == ITER_SOURCE) { kiocb_start_write(&cmd->iocb); @@ -439,84 +406,12 @@ static int lo_submit_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, ret = file->f_op->read_iter(&cmd->iocb, &iter); lo_rw_aio_do_completion(cmd); - return ret; -} - -static bool lo_backfile_support_nowait(const struct loop_device *lo) -{ - return lo->lo_backing_file->f_mode & FMODE_NOWAIT; -} -static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, - loff_t pos, int rw) -{ - int nr_bvec = lo_cmd_nr_bvec(cmd); - int ret; - - /* prepared already if we have tried nowait */ - if (!cmd->use_aio || !lo_backfile_support_nowait(lo)) { - ret = lo_rw_aio_prep(lo, cmd, nr_bvec, pos); - if (unlikely(ret)) - goto fail; - } - - cmd->iocb.ki_flags &= ~IOCB_NOWAIT; - ret = lo_submit_rw_aio(lo, cmd, nr_bvec, rw); -fail: if (ret != -EIOCBQUEUED) lo_rw_aio_complete(&cmd->iocb, ret); return -EIOCBQUEUED; } -static inline bool lo_aio_try_nowait(struct loop_device *lo, - struct loop_cmd *cmd) -{ - struct file *file = lo->lo_backing_file; - struct inode *inode = file->f_mapping->host; - struct request *rq = blk_mq_rq_from_pdu(cmd); - - /* NOWAIT works fine for backing block device */ - if (S_ISBLK(inode->i_mode)) - return true; - - /* - * NOWAIT is supposed to be fine for READ without contending with - * blocking WRITE - */ - if (req_op(rq) == REQ_OP_READ) - return true; - - /* - * If there is any queued non-NOWAIT async WRITE , don't try new - * NOWAIT WRITE for avoiding contention - * - * Here we focus on handling stable FS block mapping via NOWAIT - */ - return READ_ONCE(lo->lo_nr_blocking_writes) == 0; -} - -static int lo_rw_aio_nowait(struct loop_device *lo, struct loop_cmd *cmd, - int rw) -{ - struct request *rq = blk_mq_rq_from_pdu(cmd); - loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset; - int nr_bvec = lo_cmd_nr_bvec(cmd); - int ret = lo_rw_aio_prep(lo, cmd, nr_bvec, pos); - - if (unlikely(ret)) - goto fail; - - if (!lo_aio_try_nowait(lo, cmd)) - return -EAGAIN; - - cmd->iocb.ki_flags |= IOCB_NOWAIT; - ret = lo_submit_rw_aio(lo, cmd, nr_bvec, rw); -fail: - if (ret != -EIOCBQUEUED && ret != -EAGAIN) - lo_rw_aio_complete(&cmd->iocb, ret); - return ret; -} - static int do_req_filebacked(struct loop_device *lo, struct request *rq) { struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); @@ -811,19 +706,12 @@ static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf) return sysfs_emit(buf, "%s\n", dio ? "1" : "0"); } -static ssize_t loop_attr_nr_blocking_writes_show(struct loop_device *lo, - char *buf) -{ - return sysfs_emit(buf, "%u\n", lo->lo_nr_blocking_writes); -} - LOOP_ATTR_RO(backing_file); LOOP_ATTR_RO(offset); LOOP_ATTR_RO(sizelimit); LOOP_ATTR_RO(autoclear); LOOP_ATTR_RO(partscan); LOOP_ATTR_RO(dio); -LOOP_ATTR_RO(nr_blocking_writes); static struct attribute *loop_attrs[] = { &loop_attr_backing_file.attr, @@ -832,7 +720,6 @@ static struct attribute *loop_attrs[] = { &loop_attr_autoclear.attr, &loop_attr_partscan.attr, &loop_attr_dio.attr, - &loop_attr_nr_blocking_writes.attr, NULL, }; @@ -908,48 +795,13 @@ static inline int queue_on_root_worker(struct cgroup_subsys_state *css) } #endif -static inline void loop_inc_blocking_writes(struct loop_device *lo, - struct loop_cmd *cmd) -{ - lockdep_assert_held(&lo->lo_work_lock); - - if (req_op(blk_mq_rq_from_pdu(cmd)) == REQ_OP_WRITE) - lo->lo_nr_blocking_writes += 1; -} - -static inline void loop_dec_blocking_writes(struct loop_device *lo, - struct loop_cmd *cmd) -{ - lockdep_assert_held(&lo->lo_work_lock); - - if (req_op(blk_mq_rq_from_pdu(cmd)) == REQ_OP_WRITE) - lo->lo_nr_blocking_writes -= 1; -} - static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) { - struct request __maybe_unused *rq = blk_mq_rq_from_pdu(cmd); struct rb_node **node, *parent = NULL; struct loop_worker *cur_worker, *worker = NULL; struct work_struct *work; struct list_head *cmd_list; - /* always use the first bio's css */ - cmd->blkcg_css = NULL; - cmd->memcg_css = NULL; -#ifdef CONFIG_BLK_CGROUP - if (rq->bio) { - cmd->blkcg_css = bio_blkcg_css(rq->bio); -#ifdef CONFIG_MEMCG - if (cmd->blkcg_css) { - cmd->memcg_css = - cgroup_get_e_css(cmd->blkcg_css->cgroup, - &memory_cgrp_subsys); - } -#endif - } -#endif - spin_lock_irq(&lo->lo_work_lock); if (queue_on_root_worker(cmd->blkcg_css)) @@ -1008,8 +860,6 @@ queue_work: work = &lo->rootcg_work; cmd_list = &lo->rootcg_cmd_list; } - if (cmd->use_aio) - loop_inc_blocking_writes(lo, cmd); list_add_tail(&cmd->list_entry, cmd_list); queue_work(lo->workqueue, work); spin_unlock_irq(&lo->lo_work_lock); @@ -2006,7 +1856,6 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq = bd->rq; struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); struct loop_device *lo = rq->q->queuedata; - int rw = 0; blk_mq_start_request(rq); @@ -2019,27 +1868,26 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, case REQ_OP_WRITE_ZEROES: cmd->use_aio = false; break; - case REQ_OP_READ: - rw = ITER_DEST; - cmd->use_aio = lo->lo_flags & LO_FLAGS_DIRECT_IO; - break; - case REQ_OP_WRITE: - rw = ITER_SOURCE; + default: cmd->use_aio = lo->lo_flags & LO_FLAGS_DIRECT_IO; break; - default: - return BLK_STS_IOERR; } - /* try NOWAIT if the backing file supports the mode */ - if (cmd->use_aio && lo_backfile_support_nowait(lo)) { - int res = lo_rw_aio_nowait(lo, cmd, rw); - - if (res != -EAGAIN && res != -EOPNOTSUPP) - return BLK_STS_OK; - /* fallback to workqueue for handling aio */ + /* always use the first bio's css */ + cmd->blkcg_css = NULL; + cmd->memcg_css = NULL; +#ifdef CONFIG_BLK_CGROUP + if (rq->bio) { + cmd->blkcg_css = bio_blkcg_css(rq->bio); +#ifdef CONFIG_MEMCG + if (cmd->blkcg_css) { + cmd->memcg_css = + cgroup_get_e_css(cmd->blkcg_css->cgroup, + &memory_cgrp_subsys); + } +#endif } - +#endif loop_queue_work(lo, cmd); return BLK_STS_OK; @@ -2115,8 +1963,6 @@ static void loop_process_work(struct loop_worker *worker, cond_resched(); spin_lock_irq(&lo->lo_work_lock); - if (cmd->use_aio) - loop_dec_blocking_writes(lo, cmd); } /* @@ -2195,8 +2041,7 @@ static int loop_add(int i) lo->tag_set.queue_depth = hw_queue_depth; lo->tag_set.numa_node = NUMA_NO_NODE; lo->tag_set.cmd_size = sizeof(struct loop_cmd); - lo->tag_set.flags = BLK_MQ_F_STACKING | BLK_MQ_F_NO_SCHED_BY_DEFAULT | - BLK_MQ_F_BLOCKING; + lo->tag_set.flags = BLK_MQ_F_STACKING | BLK_MQ_F_NO_SCHED_BY_DEFAULT; lo->tag_set.driver_data = lo; err = blk_mq_alloc_tag_set(&lo->tag_set); |