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: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 7a04c16..9c4d3b2 100644 (file)
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -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
@@ -493,24 +379,8 @@ 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",
                            __func__, num_descs, ioat_chan->head,
@@ -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)

diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index f471092..5f2f9fb 100644 (file)
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -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)
 {

diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index b02b63b..6636920 100644 (file)
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -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;