[PATCH 5.4 179/191] btrfs: get rid of unique workqueue helper functions

From: Omar Sandoval osandov@fb.com

[ Upstream commit a0cac0ec961f0d42828eeef196ac2246a2f07659 ]

Commit 9e0af2376434 ("Btrfs: fix task hang under heavy compressed write") worked around the issue that a recycled work item could get a false dependency on the original work item due to how the workqueue code guarantees non-reentrancy. It did so by giving different work functions to different types of work.

However, the fixes in the previous few patches are more complete, as they prevent a work item from being recycled at all (except for a tiny window that the kernel workqueue code handles for us). This obsoletes the previous fix, so we don't need the unique helpers for correctness. The only other reason to keep them would be so they show up in stack traces, but they always seem to be optimized to a tail call, so they don't show up anyways. So, let's just get rid of the extra indirection.

While we're here, rename normal_work_helper() to the more informative btrfs_work_helper().

Reviewed-by: Nikolay Borisov nborisov@suse.com Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Omar Sandoval osandov@fb.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/async-thread.c | 58 +++++++++------------------------------- fs/btrfs/async-thread.h | 33 ++--------------------- fs/btrfs/block-group.c | 3 +-- fs/btrfs/delayed-inode.c | 4 +-- fs/btrfs/disk-io.c | 34 ++++++++--------------- fs/btrfs/inode.c | 36 ++++++++----------------- fs/btrfs/ordered-data.c | 1 - fs/btrfs/qgroup.c | 1 - fs/btrfs/raid56.c | 5 ++-- fs/btrfs/reada.c | 3 +-- fs/btrfs/scrub.c | 14 +++++----- fs/btrfs/volumes.c | 3 +-- 12 files changed, 50 insertions(+), 145 deletions(-)

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 10a04b99798a..3f3110975f88 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -53,16 +53,6 @@ struct btrfs_workqueue { struct __btrfs_workqueue *high; };

-static void normal_work_helper(struct btrfs_work *work); - -#define BTRFS_WORK_HELPER(name) \ -noinline_for_stack void btrfs_##name(struct work_struct *arg) \ -{ \ - struct btrfs_work *work = container_of(arg, struct btrfs_work, \ - normal_work); \ - normal_work_helper(work); \ -} - struct btrfs_fs_info * btrfs_workqueue_owner(const struct __btrfs_workqueue *wq) { @@ -89,29 +79,6 @@ bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq) return atomic_read(&wq->normal->pending) > wq->normal->thresh * 2; }

-BTRFS_WORK_HELPER(worker_helper); -BTRFS_WORK_HELPER(delalloc_helper); -BTRFS_WORK_HELPER(flush_delalloc_helper); -BTRFS_WORK_HELPER(cache_helper); -BTRFS_WORK_HELPER(submit_helper); -BTRFS_WORK_HELPER(fixup_helper); -BTRFS_WORK_HELPER(endio_helper); -BTRFS_WORK_HELPER(endio_meta_helper); -BTRFS_WORK_HELPER(endio_meta_write_helper); -BTRFS_WORK_HELPER(endio_raid56_helper); -BTRFS_WORK_HELPER(endio_repair_helper); -BTRFS_WORK_HELPER(rmw_helper); -BTRFS_WORK_HELPER(endio_write_helper); -BTRFS_WORK_HELPER(freespace_write_helper); -BTRFS_WORK_HELPER(delayed_meta_helper); -BTRFS_WORK_HELPER(readahead_helper); -BTRFS_WORK_HELPER(qgroup_rescan_helper); -BTRFS_WORK_HELPER(extent_refs_helper); -BTRFS_WORK_HELPER(scrub_helper); -BTRFS_WORK_HELPER(scrubwrc_helper); -BTRFS_WORK_HELPER(scrubnc_helper); -BTRFS_WORK_HELPER(scrubparity_helper); - static struct __btrfs_workqueue * __btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info, const char *name, unsigned int flags, int limit_active, int thresh) @@ -302,12 +269,13 @@ static void run_ordered_work(struct __btrfs_workqueue *wq, * original work item cannot depend on the recycled work * item in that case (see find_worker_executing_work()). * - * Note that the work of one Btrfs filesystem may depend - * on the work of another Btrfs filesystem via, e.g., a - * loop device. Therefore, we must not allow the current - * work item to be recycled until we are really done, - * otherwise we break the above assumption and can - * deadlock. + * Note that different types of Btrfs work can depend on + * each other, and one type of work on one Btrfs + * filesystem may even depend on the same type of work + * on another Btrfs filesystem via, e.g., a loop device. + * Therefore, we must not allow the current work item to + * be recycled until we are really done, otherwise we + * break the above assumption and can deadlock. */ free_self = true; } else { @@ -331,8 +299,10 @@ static void run_ordered_work(struct __btrfs_workqueue *wq, } }

-static void normal_work_helper(struct btrfs_work *work) +static void btrfs_work_helper(struct work_struct *normal_work) { + struct btrfs_work *work = container_of(normal_work, struct btrfs_work, + normal_work); struct __btrfs_workqueue *wq; void *wtag; int need_order = 0; @@ -362,15 +332,13 @@ static void normal_work_helper(struct btrfs_work *work) trace_btrfs_all_work_done(wq->fs_info, wtag); }

-void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t uniq_func, - btrfs_func_t func, - btrfs_func_t ordered_func, - btrfs_func_t ordered_free) +void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func, + btrfs_func_t ordered_func, btrfs_func_t ordered_free) { work->func = func; work->ordered_func = ordered_func; work->ordered_free = ordered_free; - INIT_WORK(&work->normal_work, uniq_func); + INIT_WORK(&work->normal_work, btrfs_work_helper); INIT_LIST_HEAD(&work->ordered_list); work->flags = 0; } diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h index 7861c9feba5f..c5bf2b117c05 100644 --- a/fs/btrfs/async-thread.h +++ b/fs/btrfs/async-thread.h @@ -29,42 +29,13 @@ struct btrfs_work { unsigned long flags; };

-#define BTRFS_WORK_HELPER_PROTO(name) \ -void btrfs_##name(struct work_struct *arg) - -BTRFS_WORK_HELPER_PROTO(worker_helper); -BTRFS_WORK_HELPER_PROTO(delalloc_helper); -BTRFS_WORK_HELPER_PROTO(flush_delalloc_helper); -BTRFS_WORK_HELPER_PROTO(cache_helper); -BTRFS_WORK_HELPER_PROTO(submit_helper); -BTRFS_WORK_HELPER_PROTO(fixup_helper); -BTRFS_WORK_HELPER_PROTO(endio_helper); -BTRFS_WORK_HELPER_PROTO(endio_meta_helper); -BTRFS_WORK_HELPER_PROTO(endio_meta_write_helper); -BTRFS_WORK_HELPER_PROTO(endio_raid56_helper); -BTRFS_WORK_HELPER_PROTO(endio_repair_helper); -BTRFS_WORK_HELPER_PROTO(rmw_helper); -BTRFS_WORK_HELPER_PROTO(endio_write_helper); -BTRFS_WORK_HELPER_PROTO(freespace_write_helper); -BTRFS_WORK_HELPER_PROTO(delayed_meta_helper); -BTRFS_WORK_HELPER_PROTO(readahead_helper); -BTRFS_WORK_HELPER_PROTO(qgroup_rescan_helper); -BTRFS_WORK_HELPER_PROTO(extent_refs_helper); -BTRFS_WORK_HELPER_PROTO(scrub_helper); -BTRFS_WORK_HELPER_PROTO(scrubwrc_helper); -BTRFS_WORK_HELPER_PROTO(scrubnc_helper); -BTRFS_WORK_HELPER_PROTO(scrubparity_helper); - - struct btrfs_workqueue *btrfs_alloc_workqueue(struct btrfs_fs_info *fs_info, const char *name, unsigned int flags, int limit_active, int thresh); -void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper, - btrfs_func_t func, - btrfs_func_t ordered_func, - btrfs_func_t ordered_free); +void btrfs_init_work(struct btrfs_work *work, btrfs_func_t func, + btrfs_func_t ordered_func, btrfs_func_t ordered_free); void btrfs_queue_work(struct btrfs_workqueue *wq, struct btrfs_work *work); void btrfs_destroy_workqueue(struct btrfs_workqueue *wq); diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 0d2da2366869..7dcfa7d7632a 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -695,8 +695,7 @@ int btrfs_cache_block_group(struct btrfs_block_group_cache *cache, caching_ctl->block_group = cache; caching_ctl->progress = cache->key.objectid; refcount_set(&caching_ctl->count, 1); - btrfs_init_work(&caching_ctl->work, btrfs_cache_helper, - caching_thread, NULL, NULL); + btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);

spin_lock(&cache->lock); /* diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 57a9ad3e8c29..c7a53e79c66d 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -1367,8 +1367,8 @@ static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root, return -ENOMEM;

async_work->delayed_root = delayed_root; - btrfs_init_work(&async_work->work, btrfs_delayed_meta_helper, - btrfs_async_run_delayed_root, NULL, NULL); + btrfs_init_work(&async_work->work, btrfs_async_run_delayed_root, NULL, + NULL); async_work->nr = nr;

btrfs_queue_work(fs_info->delayed_workers, &async_work->work); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3895c21853cc..bae334212ee2 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -706,43 +706,31 @@ static void end_workqueue_bio(struct bio *bio) struct btrfs_end_io_wq *end_io_wq = bio->bi_private; struct btrfs_fs_info *fs_info; struct btrfs_workqueue *wq; - btrfs_work_func_t func;

fs_info = end_io_wq->info; end_io_wq->status = bio->bi_status;

if (bio_op(bio) == REQ_OP_WRITE) { - if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) { + if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) wq = fs_info->endio_meta_write_workers; - func = btrfs_endio_meta_write_helper; - } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) { + else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) wq = fs_info->endio_freespace_worker; - func = btrfs_freespace_write_helper; - } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) { + else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) wq = fs_info->endio_raid56_workers; - func = btrfs_endio_raid56_helper; - } else { + else wq = fs_info->endio_write_workers; - func = btrfs_endio_write_helper; - } } else { - if (unlikely(end_io_wq->metadata == - BTRFS_WQ_ENDIO_DIO_REPAIR)) { + if (unlikely(end_io_wq->metadata == BTRFS_WQ_ENDIO_DIO_REPAIR)) wq = fs_info->endio_repair_workers; - func = btrfs_endio_repair_helper; - } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) { + else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) wq = fs_info->endio_raid56_workers; - func = btrfs_endio_raid56_helper; - } else if (end_io_wq->metadata) { + else if (end_io_wq->metadata) wq = fs_info->endio_meta_workers; - func = btrfs_endio_meta_helper; - } else { + else wq = fs_info->endio_workers; - func = btrfs_endio_helper; - } }

- btrfs_init_work(&end_io_wq->work, func, end_workqueue_fn, NULL, NULL); + btrfs_init_work(&end_io_wq->work, end_workqueue_fn, NULL, NULL); btrfs_queue_work(wq, &end_io_wq->work); }

@@ -835,8 +823,8 @@ blk_status_t btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, async->mirror_num = mirror_num; async->submit_bio_start = submit_bio_start;

- btrfs_init_work(&async->work, btrfs_worker_helper, run_one_async_start, - run_one_async_done, run_one_async_free); + btrfs_init_work(&async->work, run_one_async_start, run_one_async_done, + run_one_async_free);

async->bio_offset = bio_offset;

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index bc6e7d15577a..dc14fc2e4206 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1268,10 +1268,8 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page, async_chunk[i].write_flags = write_flags; INIT_LIST_HEAD(&async_chunk[i].extents);

- btrfs_init_work(&async_chunk[i].work, - btrfs_delalloc_helper, - async_cow_start, async_cow_submit, - async_cow_free); + btrfs_init_work(&async_chunk[i].work, async_cow_start, + async_cow_submit, async_cow_free);

nr_pages = DIV_ROUND_UP(cur_end - start, PAGE_SIZE); atomic_add(nr_pages, &fs_info->async_delalloc_pages); @@ -2264,8 +2262,7 @@ int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end)

SetPageChecked(page); get_page(page); - btrfs_init_work(&fixup->work, btrfs_fixup_helper, - btrfs_writepage_fixup_worker, NULL, NULL); + btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL); fixup->page = page; btrfs_queue_work(fs_info->fixup_workers, &fixup->work); return -EBUSY; @@ -3258,7 +3255,6 @@ void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start, struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_ordered_extent *ordered_extent = NULL; struct btrfs_workqueue *wq; - btrfs_work_func_t func;

trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);

@@ -3267,16 +3263,12 @@ void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start, end - start + 1, uptodate)) return;

- if (btrfs_is_free_space_inode(BTRFS_I(inode))) { + if (btrfs_is_free_space_inode(BTRFS_I(inode))) wq = fs_info->endio_freespace_worker; - func = btrfs_freespace_write_helper; - } else { + else wq = fs_info->endio_write_workers; - func = btrfs_endio_write_helper; - }

- btrfs_init_work(&ordered_extent->work, func, finish_ordered_fn, NULL, - NULL); + btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL); btrfs_queue_work(wq, &ordered_extent->work); }

@@ -8213,18 +8205,14 @@ static void __endio_write_update_ordered(struct inode *inode, struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_ordered_extent *ordered = NULL; struct btrfs_workqueue *wq; - btrfs_work_func_t func; u64 ordered_offset = offset; u64 ordered_bytes = bytes; u64 last_offset;

- if (btrfs_is_free_space_inode(BTRFS_I(inode))) { + if (btrfs_is_free_space_inode(BTRFS_I(inode))) wq = fs_info->endio_freespace_worker; - func = btrfs_freespace_write_helper; - } else { + else wq = fs_info->endio_write_workers; - func = btrfs_endio_write_helper; - }

while (ordered_offset < offset + bytes) { last_offset = ordered_offset; @@ -8232,9 +8220,8 @@ static void __endio_write_update_ordered(struct inode *inode, &ordered_offset, ordered_bytes, uptodate)) { - btrfs_init_work(&ordered->work, func, - finish_ordered_fn, - NULL, NULL); + btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, + NULL); btrfs_queue_work(wq, &ordered->work); } /* @@ -10119,8 +10106,7 @@ static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode init_completion(&work->completion); INIT_LIST_HEAD(&work->list); work->inode = inode; - btrfs_init_work(&work->work, btrfs_flush_delalloc_helper, - btrfs_run_delalloc_work, NULL, NULL); + btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);

return work; } diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 24b6c72b9a59..6240a5a1f2c0 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -547,7 +547,6 @@ u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr, spin_unlock(&root->ordered_extent_lock);

btrfs_init_work(&ordered->flush_work, - btrfs_flush_delalloc_helper, btrfs_run_ordered_extent_work, NULL, NULL); list_add_tail(&ordered->work_list, &works); btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work); diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 3ad151655eb8..27a903aaf43b 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -3280,7 +3280,6 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid, memset(&fs_info->qgroup_rescan_work, 0, sizeof(fs_info->qgroup_rescan_work)); btrfs_init_work(&fs_info->qgroup_rescan_work, - btrfs_qgroup_rescan_helper, btrfs_qgroup_rescan_worker, NULL, NULL); return 0; } diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index 57a2ac721985..8f47a85944eb 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -190,7 +190,7 @@ static void scrub_parity_work(struct btrfs_work *work);

static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func) { - btrfs_init_work(&rbio->work, btrfs_rmw_helper, work_func, NULL, NULL); + btrfs_init_work(&rbio->work, work_func, NULL, NULL); btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work); }

@@ -1743,8 +1743,7 @@ static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule) plug = container_of(cb, struct btrfs_plug_cb, cb);

if (from_schedule) { - btrfs_init_work(&plug->work, btrfs_rmw_helper, - unplug_work, NULL, NULL); + btrfs_init_work(&plug->work, unplug_work, NULL, NULL); btrfs_queue_work(plug->info->rmw_workers, &plug->work); return; diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c index dd4f9c2b7107..1feaeadc8cf5 100644 --- a/fs/btrfs/reada.c +++ b/fs/btrfs/reada.c @@ -819,8 +819,7 @@ static void reada_start_machine(struct btrfs_fs_info *fs_info) /* FIXME we cannot handle this properly right now */ BUG(); } - btrfs_init_work(&rmw->work, btrfs_readahead_helper, - reada_start_machine_worker, NULL, NULL); + btrfs_init_work(&rmw->work, reada_start_machine_worker, NULL, NULL); rmw->fs_info = fs_info;

btrfs_queue_work(fs_info->readahead_workers, &rmw->work); diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index a0770a6aee00..a7b043fd7a57 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -598,8 +598,8 @@ static noinline_for_stack struct scrub_ctx *scrub_setup_ctx( sbio->index = i; sbio->sctx = sctx; sbio->page_count = 0; - btrfs_init_work(&sbio->work, btrfs_scrub_helper, - scrub_bio_end_io_worker, NULL, NULL); + btrfs_init_work(&sbio->work, scrub_bio_end_io_worker, NULL, + NULL);

if (i != SCRUB_BIOS_PER_SCTX - 1) sctx->bios[i]->next_free = i + 1; @@ -1720,8 +1720,7 @@ static void scrub_wr_bio_end_io(struct bio *bio) sbio->status = bio->bi_status; sbio->bio = bio;

- btrfs_init_work(&sbio->work, btrfs_scrubwrc_helper, - scrub_wr_bio_end_io_worker, NULL, NULL); + btrfs_init_work(&sbio->work, scrub_wr_bio_end_io_worker, NULL, NULL); btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work); }

@@ -2203,8 +2202,7 @@ static void scrub_missing_raid56_pages(struct scrub_block *sblock) raid56_add_scrub_pages(rbio, spage->page, spage->logical); }

- btrfs_init_work(&sblock->work, btrfs_scrub_helper, - scrub_missing_raid56_worker, NULL, NULL); + btrfs_init_work(&sblock->work, scrub_missing_raid56_worker, NULL, NULL); scrub_block_get(sblock); scrub_pending_bio_inc(sctx); raid56_submit_missing_rbio(rbio); @@ -2742,8 +2740,8 @@ static void scrub_parity_bio_endio(struct bio *bio)

bio_put(bio);

- btrfs_init_work(&sparity->work, btrfs_scrubparity_helper, - scrub_parity_bio_endio_worker, NULL, NULL); + btrfs_init_work(&sparity->work, scrub_parity_bio_endio_worker, NULL, + NULL); btrfs_queue_work(fs_info->scrub_parity_workers, &sparity->work); }

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e04409f85063..d8d7b1ee83ca 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6676,8 +6676,7 @@ struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info, else generate_random_uuid(dev->uuid);

- btrfs_init_work(&dev->work, btrfs_submit_helper, - pending_bios_fn, NULL, NULL); + btrfs_init_work(&dev->work, pending_bios_fn, NULL, NULL);

return dev; }