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authorLior Amsalem <alior@marvell.com>2015-05-26 15:07:36 +0200
committerVinod Koul <vinod.koul@intel.com>2015-06-10 22:18:31 +0530
commitfbea28a2afb4251f985af52eb0180f097acaee16 (patch)
treef8f88b492c57092e095878d3d59bfbfabecc1fcc /drivers/dma/mv_xor.c
parentf1d25e0a9b1a6519580ddf5a7e5538093a504fcd (diff)
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 <alior@marvell.com> Reviewed-by: Ofer Heifetz <oferh@marvell.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/mv_xor.c')
-rw-r--r--drivers/dma/mv_xor.c141
1 files changed, 47 insertions, 94 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);