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Message-Id: <1432645656-20504-6-git-send-email-maxime.ripard@free-electrons.com>
Date: Tue, 26 May 2015 15:07:36 +0200
From: Maxime Ripard <maxime.ripard@...e-electrons.com>
To: Vinod Koul <vinod.koul@...el.com>,
Gregory Clement <gregory.clement@...e-electrons.com>,
Jason Cooper <jason@...edaemon.net>,
Andrew Lunn <andrew@...n.ch>,
Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
Cc: dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, Lior Amsalem <alior@...vell.com>,
Thomas Petazzoni <thomas@...e-electrons.com>,
Maxime Ripard <maxime.ripard@...e-electrons.com>
Subject: [PATCH v2 5/5] dmaengine: mv_xor: improve descriptors list handling and reduce locking
From: Lior Amsalem <alior@...vell.com>
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 <alior@...vell.com>
Reviewed-by: Ofer Heifetz <oferh@...vell.com>
Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
---
drivers/dma/mv_xor.c | 141 +++++++++++++++++----------------------------------
drivers/dma/mv_xor.h | 17 +++----
2 files changed, 53 insertions(+), 105 deletions(-)
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);
diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
index 6b10c8c647b9..b7455b42137b 100644
--- a/drivers/dma/mv_xor.h
+++ b/drivers/dma/mv_xor.h
@@ -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;
};
--
2.4.1
--
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