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Commit fbea28a2 authored by Lior Amsalem's avatar Lior Amsalem Committed by Vinod Koul
Browse files

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: default avatarLior Amsalem <alior@marvell.com>
Reviewed-by: default avatarOfer Heifetz <oferh@marvell.com>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent f1d25e0a

drivers/dma/mv_xor.c

+47 −94
Original line number Diff line number Diff line
@@ -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,

	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,

			slot_node);

					node);



	list_for_each_entry_safe_continue(

		iter, _iter, &mv_chan->all_slots, slot_node) {

		list_move_tail(&iter->node, &mv_chan->allocated_slots);



		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_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);

drivers/dma/mv_xor.h

+6 −11
Original line number Diff line number Diff line
@@ -94,11 +94,11 @@ struct mv_xor_device { 
 * @mmr_base: memory mapped register base

 * @idx: the index of the xor channel

 * @chain: device chain view of the descriptors

 * @free_slots: free slots usable by the channel

 * @allocated_slots: slots allocated by the driver

 * @completed_slots: slots completed by HW but still need to be acked

 * @device: parent device

 * @common: common dmaengine channel object members

 * @last_used: place holder for allocation to continue from where it left off

 * @all_slots: complete domain of slots usable by the channel

 * @slots_allocated: records the actual size of the descriptor slot pool

 * @irq_tasklet: bottom half where mv_xor_slot_cleanup runs

 * @op_in_desc: new mode of driver, each op is writen to descriptor.
@@ -112,14 +112,14 @@ struct mv_xor_chan { 
	int                     irq;

	enum dma_transaction_type	current_type;

	struct list_head	chain;

	struct list_head	free_slots;

	struct list_head	allocated_slots;

	struct list_head	completed_slots;

	dma_addr_t		dma_desc_pool;

	void			*dma_desc_pool_virt;

	size_t                  pool_size;

	struct dma_device	dmadev;

	struct dma_chan		dmachan;

	struct mv_xor_desc_slot	*last_used;

	struct list_head	all_slots;

	int			slots_allocated;

	struct tasklet_struct	irq_tasklet;

	int                     op_in_desc;
@@ -130,9 +130,7 @@ struct mv_xor_chan { 


/**

 * struct mv_xor_desc_slot - software descriptor

 * @slot_node: node on the mv_xor_chan.all_slots list

 * @chain_node: node on the mv_xor_chan.chain list

 * @completed_node: node on the mv_xor_chan.completed_slots list

 * @node: node on the mv_xor_chan lists

 * @hw_desc: virtual address of the hardware descriptor chain

 * @phys: hardware address of the hardware descriptor chain

 * @slot_used: slot in use or not
@@ -141,12 +139,9 @@ struct mv_xor_chan { 
 * @async_tx: support for the async_tx api

 */

struct mv_xor_desc_slot {

	struct list_head	slot_node;

	struct list_head	chain_node;

	struct list_head	completed_node;

	struct list_head	node;

	enum dma_transaction_type	type;

	void			*hw_desc;

	u16			slot_used;

	u16			idx;

	struct dma_async_tx_descriptor	async_tx;

};