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Commit cd60cd96 authored by Dave Jiang's avatar Dave Jiang Committed by Vinod Koul
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dmaengine: IOATDMA: Removing descriptor ring reshape 



Moving to contingous memory backed descriptor rings. This makes is really
difficult and complex to do reshape. Going to remove this as I don't think
we need to do it anymore.

Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 679cfbf7

drivers/dma/ioat/dma.c

+0 −143
Original line number Diff line number Diff line
@@ -332,9 +332,6 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags) 
	int descs = 1 << order;

	int i;



	if (order > ioat_get_max_alloc_order())

		return NULL;



	/* allocate the array to hold the software ring */

	ring = kcalloc(descs, sizeof(*ring), flags);

	if (!ring)
@@ -362,114 +359,6 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags) 
	return ring;

}



static bool reshape_ring(struct ioatdma_chan *ioat_chan, int order)

{

	/* reshape differs from normal ring allocation in that we want

	 * to allocate a new software ring while only

	 * extending/truncating the hardware ring

	 */

	struct dma_chan *c = &ioat_chan->dma_chan;

	const u32 curr_size = ioat_ring_size(ioat_chan);

	const u16 active = ioat_ring_active(ioat_chan);

	const u32 new_size = 1 << order;

	struct ioat_ring_ent **ring;

	u32 i;



	if (order > ioat_get_max_alloc_order())

		return false;



	/* double check that we have at least 1 free descriptor */

	if (active == curr_size)

		return false;



	/* when shrinking, verify that we can hold the current active

	 * set in the new ring

	 */

	if (active >= new_size)

		return false;



	/* allocate the array to hold the software ring */

	ring = kcalloc(new_size, sizeof(*ring), GFP_NOWAIT);

	if (!ring)

		return false;



	/* allocate/trim descriptors as needed */

	if (new_size > curr_size) {

		/* copy current descriptors to the new ring */

		for (i = 0; i < curr_size; i++) {

			u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);

			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);



			ring[new_idx] = ioat_chan->ring[curr_idx];

			set_desc_id(ring[new_idx], new_idx);

		}



		/* add new descriptors to the ring */

		for (i = curr_size; i < new_size; i++) {

			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);



			ring[new_idx] = ioat_alloc_ring_ent(c, GFP_NOWAIT);

			if (!ring[new_idx]) {

				while (i--) {

					u16 new_idx = (ioat_chan->tail+i) &

						       (new_size-1);



					ioat_free_ring_ent(ring[new_idx], c);

				}

				kfree(ring);

				return false;

			}

			set_desc_id(ring[new_idx], new_idx);

		}



		/* hw link new descriptors */

		for (i = curr_size-1; i < new_size; i++) {

			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);

			struct ioat_ring_ent *next =

				ring[(new_idx+1) & (new_size-1)];

			struct ioat_dma_descriptor *hw = ring[new_idx]->hw;



			hw->next = next->txd.phys;

		}

	} else {

		struct ioat_dma_descriptor *hw;

		struct ioat_ring_ent *next;



		/* copy current descriptors to the new ring, dropping the

		 * removed descriptors

		 */

		for (i = 0; i < new_size; i++) {

			u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);

			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);



			ring[new_idx] = ioat_chan->ring[curr_idx];

			set_desc_id(ring[new_idx], new_idx);

		}



		/* free deleted descriptors */

		for (i = new_size; i < curr_size; i++) {

			struct ioat_ring_ent *ent;



			ent = ioat_get_ring_ent(ioat_chan, ioat_chan->tail+i);

			ioat_free_ring_ent(ent, c);

		}



		/* fix up hardware ring */

		hw = ring[(ioat_chan->tail+new_size-1) & (new_size-1)]->hw;

		next = ring[(ioat_chan->tail+new_size) & (new_size-1)];

		hw->next = next->txd.phys;

	}



	dev_dbg(to_dev(ioat_chan), "%s: allocated %d descriptors\n",

		__func__, new_size);



	kfree(ioat_chan->ring);

	ioat_chan->ring = ring;

	ioat_chan->alloc_order = order;



	return true;

}



/**

 * ioat_check_space_lock - verify space and grab ring producer lock

 * @ioat: ioat,3 channel (ring) to operate on
@@ -478,9 +367,6 @@ static bool reshape_ring(struct ioatdma_chan *ioat_chan, int order) 
int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)

	__acquires(&ioat_chan->prep_lock)

{

	bool retry;



 retry:

	spin_lock_bh(&ioat_chan->prep_lock);

	/* never allow the last descriptor to be consumed, we need at

	 * least one free at all times to allow for on-the-fly ring
@@ -493,23 +379,7 @@ int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs) 
		ioat_chan->produce = num_descs;

		return 0;  /* with ioat->prep_lock held */

	}

	retry = test_and_set_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);

	spin_unlock_bh(&ioat_chan->prep_lock);



	/* is another cpu already trying to expand the ring? */

	if (retry)

		goto retry;



	spin_lock_bh(&ioat_chan->cleanup_lock);

	spin_lock_bh(&ioat_chan->prep_lock);

	retry = reshape_ring(ioat_chan, ioat_chan->alloc_order + 1);

	clear_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);

	spin_unlock_bh(&ioat_chan->prep_lock);

	spin_unlock_bh(&ioat_chan->cleanup_lock);



	/* if we were able to expand the ring retry the allocation */

	if (retry)

		goto retry;



	dev_dbg_ratelimited(to_dev(ioat_chan),

			    "%s: ring full! num_descs: %d (%x:%x:%x)\n",
@@ -823,19 +693,6 @@ static void check_active(struct ioatdma_chan *ioat_chan) 


	if (test_and_clear_bit(IOAT_CHAN_ACTIVE, &ioat_chan->state))

		mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);

	else if (ioat_chan->alloc_order > ioat_get_alloc_order()) {

		/* if the ring is idle, empty, and oversized try to step

		 * down the size

		 */

		reshape_ring(ioat_chan, ioat_chan->alloc_order - 1);



		/* keep shrinking until we get back to our minimum

		 * default size

		 */

		if (ioat_chan->alloc_order > ioat_get_alloc_order())

			mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);

	}



}



void ioat_timer_event(unsigned long data)

drivers/dma/ioat/dma.h

+0 −5
Original line number Diff line number Diff line
@@ -100,7 +100,6 @@ struct ioatdma_chan { 
	#define IOAT_COMPLETION_ACK 1

	#define IOAT_RESET_PENDING 2

	#define IOAT_KOBJ_INIT_FAIL 3

	#define IOAT_RESHAPE_PENDING 4

	#define IOAT_RUN 5

	#define IOAT_CHAN_ACTIVE 6

	struct timer_list timer;
@@ -302,10 +301,6 @@ static inline bool is_ioat_bug(unsigned long err) 
}



#define IOAT_MAX_ORDER 16

#define ioat_get_alloc_order() \

	(min(ioat_ring_alloc_order, IOAT_MAX_ORDER))

#define ioat_get_max_alloc_order() \

	(min(ioat_ring_max_alloc_order, IOAT_MAX_ORDER))



static inline u32 ioat_ring_size(struct ioatdma_chan *ioat_chan)

{

drivers/dma/ioat/init.c

+1 −9
Original line number Diff line number Diff line
@@ -136,14 +136,6 @@ int ioat_pending_level = 4; 
module_param(ioat_pending_level, int, 0644);

MODULE_PARM_DESC(ioat_pending_level,

		 "high-water mark for pushing ioat descriptors (default: 4)");

int ioat_ring_alloc_order = 8;

module_param(ioat_ring_alloc_order, int, 0644);

MODULE_PARM_DESC(ioat_ring_alloc_order,

		 "ioat+: allocate 2^n descriptors per channel (default: 8 max: 16)");

int ioat_ring_max_alloc_order = IOAT_MAX_ORDER;

module_param(ioat_ring_max_alloc_order, int, 0644);

MODULE_PARM_DESC(ioat_ring_max_alloc_order,

		 "ioat+: upper limit for ring size (default: 16)");

static char ioat_interrupt_style[32] = "msix";

module_param_string(ioat_interrupt_style, ioat_interrupt_style,

		    sizeof(ioat_interrupt_style), 0644);
@@ -712,7 +704,7 @@ static int ioat_alloc_chan_resources(struct dma_chan *c) 
	writel(((u64)ioat_chan->completion_dma) >> 32,

	       ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);



	order = ioat_get_alloc_order();

	order = IOAT_MAX_ORDER;

	ring = ioat_alloc_ring(c, order, GFP_KERNEL);

	if (!ring)

		return -ENOMEM;