From fbea28a2afb4251f985af52eb0180f097acaee16 Mon Sep 17 00:00:00 2001 From: Lior Amsalem Date: Tue, 26 May 2015 15:07:36 +0200 Subject: dmaengine: mv_xor: improve descriptors list handling and reduce locking This patch change the way free descriptors are marked. Instead of having a field for descriptor in use, all the descriptors in the all_slots list are free for use. This simplify the allocation method and reduce the locking needed. Signed-off-by: Lior Amsalem Reviewed-by: Ofer Heifetz Signed-off-by: Maxime Ripard Signed-off-by: Vinod Koul --- drivers/dma/mv_xor.c | 141 +++++++++++++++++---------------------------------- 1 file changed, 47 insertions(+), 94 deletions(-) (limited to 'drivers/dma/mv_xor.c') diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index 669d0b5029d1..fbaf1ead2597 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -88,12 +88,6 @@ static void mv_desc_set_next_desc(struct mv_xor_desc_slot *desc, hw_desc->phy_next_desc = next_desc_addr; } -static void mv_desc_clear_next_desc(struct mv_xor_desc_slot *desc) -{ - struct mv_xor_desc *hw_desc = desc->hw_desc; - hw_desc->phy_next_desc = 0; -} - static void mv_desc_set_src_addr(struct mv_xor_desc_slot *desc, int index, dma_addr_t addr) { @@ -213,21 +207,6 @@ static char mv_chan_is_busy(struct mv_xor_chan *chan) return (state == 1) ? 1 : 0; } -/** - * mv_chan_free_slots - flags descriptor slots for reuse - * @slot: Slot to free - * Caller must hold &mv_chan->lock while calling this function - */ -static void mv_chan_free_slots(struct mv_xor_chan *mv_chan, - struct mv_xor_desc_slot *slot) -{ - dev_dbg(mv_chan_to_devp(mv_chan), "%s %d slot %p\n", - __func__, __LINE__, slot); - - slot->slot_used = 0; - -} - /* * mv_chan_start_new_chain - program the engine to operate on new * chain headed by sw_desc @@ -279,12 +258,10 @@ mv_chan_clean_completed_slots(struct mv_xor_chan *mv_chan) dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__); list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots, - completed_node) { + node) { - if (async_tx_test_ack(&iter->async_tx)) { - list_del(&iter->completed_node); - mv_chan_free_slots(mv_chan, iter); - } + if (async_tx_test_ack(&iter->async_tx)) + list_move_tail(&iter->node, &mv_chan->free_slots); } return 0; } @@ -295,17 +272,16 @@ mv_desc_clean_slot(struct mv_xor_desc_slot *desc, { dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: desc %p flags %d\n", __func__, __LINE__, desc, desc->async_tx.flags); - list_del(&desc->chain_node); + /* the client is allowed to attach dependent operations * until 'ack' is set */ - if (!async_tx_test_ack(&desc->async_tx)) { + if (!async_tx_test_ack(&desc->async_tx)) /* move this slot to the completed_slots */ - list_add_tail(&desc->completed_node, &mv_chan->completed_slots); - return 0; - } + list_move_tail(&desc->node, &mv_chan->completed_slots); + else + list_move_tail(&desc->node, &mv_chan->free_slots); - mv_chan_free_slots(mv_chan, desc); return 0; } @@ -328,7 +304,7 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan) */ list_for_each_entry_safe(iter, _iter, &mv_chan->chain, - chain_node) { + node) { /* clean finished descriptors */ hw_desc = iter->hw_desc; @@ -360,17 +336,17 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan) */ iter = list_entry(mv_chan->chain.next, struct mv_xor_desc_slot, - chain_node); + node); mv_chan_start_new_chain(mv_chan, iter); } else { - if (!list_is_last(&iter->chain_node, &mv_chan->chain)) { + if (!list_is_last(&iter->node, &mv_chan->chain)) { /* * descriptors are still waiting after * current, trigger them */ - iter = list_entry(iter->chain_node.next, + iter = list_entry(iter->node.next, struct mv_xor_desc_slot, - chain_node); + node); mv_chan_start_new_chain(mv_chan, iter); } else { /* @@ -398,49 +374,28 @@ static void mv_xor_tasklet(unsigned long data) static struct mv_xor_desc_slot * mv_chan_alloc_slot(struct mv_xor_chan *mv_chan) { - struct mv_xor_desc_slot *iter, *_iter; - int retry = 0; + struct mv_xor_desc_slot *iter; - /* start search from the last allocated descrtiptor - * if a contiguous allocation can not be found start searching - * from the beginning of the list - */ -retry: - if (retry == 0) - iter = mv_chan->last_used; - else - iter = list_entry(&mv_chan->all_slots, - struct mv_xor_desc_slot, - slot_node); - - list_for_each_entry_safe_continue( - iter, _iter, &mv_chan->all_slots, slot_node) { - - prefetch(_iter); - prefetch(&_iter->async_tx); - if (iter->slot_used) { - /* give up after finding the first busy slot - * on the second pass through the list - */ - if (retry) - break; - continue; - } + spin_lock_bh(&mv_chan->lock); + + if (!list_empty(&mv_chan->free_slots)) { + iter = list_first_entry(&mv_chan->free_slots, + struct mv_xor_desc_slot, + node); + + list_move_tail(&iter->node, &mv_chan->allocated_slots); + + spin_unlock_bh(&mv_chan->lock); /* pre-ack descriptor */ async_tx_ack(&iter->async_tx); - - iter->slot_used = 1; - INIT_LIST_HEAD(&iter->chain_node); iter->async_tx.cookie = -EBUSY; - mv_chan->last_used = iter; - mv_desc_clear_next_desc(iter); return iter; } - if (!retry++) - goto retry; + + spin_unlock_bh(&mv_chan->lock); /* try to free some slots if the allocation fails */ tasklet_schedule(&mv_chan->irq_tasklet); @@ -466,14 +421,14 @@ mv_xor_tx_submit(struct dma_async_tx_descriptor *tx) cookie = dma_cookie_assign(tx); if (list_empty(&mv_chan->chain)) - list_add_tail(&sw_desc->chain_node, &mv_chan->chain); + list_move_tail(&sw_desc->node, &mv_chan->chain); else { new_hw_chain = 0; old_chain_tail = list_entry(mv_chan->chain.prev, struct mv_xor_desc_slot, - chain_node); - list_add_tail(&sw_desc->chain_node, &mv_chan->chain); + node); + list_move_tail(&sw_desc->node, &mv_chan->chain); dev_dbg(mv_chan_to_devp(mv_chan), "Append to last desc %pa\n", &old_chain_tail->async_tx.phys); @@ -526,26 +481,20 @@ static int mv_xor_alloc_chan_resources(struct dma_chan *chan) dma_async_tx_descriptor_init(&slot->async_tx, chan); slot->async_tx.tx_submit = mv_xor_tx_submit; - INIT_LIST_HEAD(&slot->chain_node); - INIT_LIST_HEAD(&slot->slot_node); + INIT_LIST_HEAD(&slot->node); dma_desc = mv_chan->dma_desc_pool; slot->async_tx.phys = dma_desc + idx * MV_XOR_SLOT_SIZE; slot->idx = idx++; spin_lock_bh(&mv_chan->lock); mv_chan->slots_allocated = idx; - list_add_tail(&slot->slot_node, &mv_chan->all_slots); + list_add_tail(&slot->node, &mv_chan->free_slots); spin_unlock_bh(&mv_chan->lock); } - if (mv_chan->slots_allocated && !mv_chan->last_used) - mv_chan->last_used = list_entry(mv_chan->all_slots.next, - struct mv_xor_desc_slot, - slot_node); - dev_dbg(mv_chan_to_devp(mv_chan), - "allocated %d descriptor slots last_used: %p\n", - mv_chan->slots_allocated, mv_chan->last_used); + "allocated %d descriptor slots\n", + mv_chan->slots_allocated); return mv_chan->slots_allocated ? : -ENOMEM; } @@ -566,7 +515,6 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src, "%s src_cnt: %d len: %u dest %pad flags: %ld\n", __func__, src_cnt, len, &dest, flags); - spin_lock_bh(&mv_chan->lock); sw_desc = mv_chan_alloc_slot(mv_chan); if (sw_desc) { sw_desc->type = DMA_XOR; @@ -577,7 +525,7 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src, while (src_cnt--) mv_desc_set_src_addr(sw_desc, src_cnt, src[src_cnt]); } - spin_unlock_bh(&mv_chan->lock); + dev_dbg(mv_chan_to_devp(mv_chan), "%s sw_desc %p async_tx %p \n", __func__, sw_desc, &sw_desc->async_tx); @@ -624,22 +572,26 @@ static void mv_xor_free_chan_resources(struct dma_chan *chan) mv_chan_slot_cleanup(mv_chan); list_for_each_entry_safe(iter, _iter, &mv_chan->chain, - chain_node) { + node) { in_use_descs++; - list_del(&iter->chain_node); + list_move_tail(&iter->node, &mv_chan->free_slots); } list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots, - completed_node) { + node) { + in_use_descs++; + list_move_tail(&iter->node, &mv_chan->free_slots); + } + list_for_each_entry_safe(iter, _iter, &mv_chan->allocated_slots, + node) { in_use_descs++; - list_del(&iter->completed_node); + list_move_tail(&iter->node, &mv_chan->free_slots); } list_for_each_entry_safe_reverse( - iter, _iter, &mv_chan->all_slots, slot_node) { - list_del(&iter->slot_node); + iter, _iter, &mv_chan->free_slots, node) { + list_del(&iter->node); kfree(iter); mv_chan->slots_allocated--; } - mv_chan->last_used = NULL; dev_dbg(mv_chan_to_devp(mv_chan), "%s slots_allocated %d\n", __func__, mv_chan->slots_allocated); @@ -1097,7 +1049,8 @@ mv_xor_channel_add(struct mv_xor_device *xordev, spin_lock_init(&mv_chan->lock); INIT_LIST_HEAD(&mv_chan->chain); INIT_LIST_HEAD(&mv_chan->completed_slots); - INIT_LIST_HEAD(&mv_chan->all_slots); + INIT_LIST_HEAD(&mv_chan->free_slots); + INIT_LIST_HEAD(&mv_chan->allocated_slots); mv_chan->dmachan.device = dma_dev; dma_cookie_init(&mv_chan->dmachan); -- cgit v1.2.1