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Commit 281befa5 authored by Dan Williams's avatar Dan Williams
Browse files

ioat2: kill pending flag 



The pending == 2 case no longer exists in the driver so, we can use
ioat2_ring_pending() outside the lock to determine if there might be any
descriptors in the ring that the hardware has not seen.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent b372ec2d

drivers/dma/ioat/dma_v2.c

+12 −22
Original line number Diff line number Diff line
@@ -51,48 +51,40 @@ MODULE_PARM_DESC(ioat_ring_max_alloc_order, 


void __ioat2_issue_pending(struct ioat2_dma_chan *ioat)

{

	void * __iomem reg_base = ioat->base.reg_base;

	struct ioat_chan_common *chan = &ioat->base;



	ioat->pending = 0;

	ioat->dmacount += ioat2_ring_pending(ioat);

	ioat->issued = ioat->head;

	/* make descriptor updates globally visible before notifying channel */

	wmb();

	writew(ioat->dmacount, reg_base + IOAT_CHAN_DMACOUNT_OFFSET);

	dev_dbg(to_dev(&ioat->base),

	writew(ioat->dmacount, chan->reg_base + IOAT_CHAN_DMACOUNT_OFFSET);

	dev_dbg(to_dev(chan),

		"%s: head: %#x tail: %#x issued: %#x count: %#x\n",

		__func__, ioat->head, ioat->tail, ioat->issued, ioat->dmacount);

}



void ioat2_issue_pending(struct dma_chan *chan)

void ioat2_issue_pending(struct dma_chan *c)

{

	struct ioat2_dma_chan *ioat = to_ioat2_chan(chan);

	struct ioat2_dma_chan *ioat = to_ioat2_chan(c);



	if (ioat2_ring_pending(ioat)) {

		spin_lock_bh(&ioat->ring_lock);

	if (ioat->pending == 1)

		__ioat2_issue_pending(ioat);

		spin_unlock_bh(&ioat->ring_lock);

	}

}



/**

 * ioat2_update_pending - log pending descriptors

 * @ioat: ioat2+ channel

 *

 * set pending to '1' unless pending is already set to '2', pending == 2

 * indicates that submission is temporarily blocked due to an in-flight

 * reset.  If we are already above the ioat_pending_level threshold then

 * just issue pending.

 *

 * called with ring_lock held

 * Check if the number of unsubmitted descriptors has exceeded the

 * watermark.  Called with ring_lock held

 */

static void ioat2_update_pending(struct ioat2_dma_chan *ioat)

{

	if (unlikely(ioat->pending == 2))

		return;

	else if (ioat2_ring_pending(ioat) > ioat_pending_level)

	if (ioat2_ring_pending(ioat) > ioat_pending_level)

		__ioat2_issue_pending(ioat);

	else

		ioat->pending = 1;

}



static void __ioat2_start_null_desc(struct ioat2_dma_chan *ioat)
@@ -546,7 +538,6 @@ int ioat2_alloc_chan_resources(struct dma_chan *c) 
	ioat->head = 0;

	ioat->issued = 0;

	ioat->tail = 0;

	ioat->pending = 0;

	ioat->alloc_order = order;

	spin_unlock_bh(&ioat->ring_lock);
@@ -815,7 +806,6 @@ void ioat2_free_chan_resources(struct dma_chan *c) 


	chan->last_completion = 0;

	chan->completion_dma = 0;

	ioat->pending = 0;

	ioat->dmacount = 0;

}

drivers/dma/ioat/dma_v2.h

+0 −2
Original line number Diff line number Diff line
@@ -47,7 +47,6 @@ extern int ioat_ring_alloc_order; 
 * @head: allocated index

 * @issued: hardware notification point

 * @tail: cleanup index

 * @pending: lock free indicator for issued != head

 * @dmacount: identical to 'head' except for occasionally resetting to zero

 * @alloc_order: log2 of the number of allocated descriptors

 * @ring: software ring buffer implementation of hardware ring
@@ -61,7 +60,6 @@ struct ioat2_dma_chan { 
	u16 tail;

	u16 dmacount;

	u16 alloc_order;

	int pending;

	struct ioat_ring_ent **ring;

	spinlock_t ring_lock;

};