1 files changed, 95 insertions, 90 deletions

diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index f540e0be7f31..3c8b32a83794 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -27,6 +27,7 @@
 
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/pci.h>
 #include <linux/interrupt.h>
 #include <linux/dmaengine.h>
@@ -55,8 +56,6 @@ void __ioat2_issue_pending(struct ioat2_dma_chan *ioat)
 
         ioat->dmacount += ioat2_ring_pending(ioat);
         ioat->issued = ioat->head;
-        /* make descriptor updates globally visible before notifying channel */
-        wmb();
         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",
@@ -68,9 +67,9 @@ void ioat2_issue_pending(struct dma_chan *c)
         struct ioat2_dma_chan *ioat = to_ioat2_chan(c);
 
         if (ioat2_ring_pending(ioat)) {
-                spin_lock_bh(&ioat->ring_lock);
+                spin_lock_bh(&ioat->prep_lock);
                 __ioat2_issue_pending(ioat);
-                spin_unlock_bh(&ioat->ring_lock);
+                spin_unlock_bh(&ioat->prep_lock);
         }
 }
 
@@ -79,7 +78,7 @@ void ioat2_issue_pending(struct dma_chan *c)
  * @ioat: ioat2+ channel
  *
  * Check if the number of unsubmitted descriptors has exceeded the
- * watermark.  Called with ring_lock held
+ * watermark.  Called with prep_lock held
  */
 static void ioat2_update_pending(struct ioat2_dma_chan *ioat)
 {
@@ -91,7 +90,6 @@ static void __ioat2_start_null_desc(struct ioat2_dma_chan *ioat)
 {
         struct ioat_ring_ent *desc;
         struct ioat_dma_descriptor *hw;
-        int idx;
 
         if (ioat2_ring_space(ioat) < 1) {
                 dev_err(to_dev(&ioat->base),
@@ -101,8 +99,7 @@ static void __ioat2_start_null_desc(struct ioat2_dma_chan *ioat)
 
         dev_dbg(to_dev(&ioat->base), "%s: head: %#x tail: %#x issued: %#x\n",
                 __func__, ioat->head, ioat->tail, ioat->issued);
-        idx = ioat2_desc_alloc(ioat, 1);
-        desc = ioat2_get_ring_ent(ioat, idx);
+        desc = ioat2_get_ring_ent(ioat, ioat->head);
 
         hw = desc->hw;
         hw->ctl = 0;
@@ -116,14 +113,16 @@ static void __ioat2_start_null_desc(struct ioat2_dma_chan *ioat)
         async_tx_ack(&desc->txd);
         ioat2_set_chainaddr(ioat, desc->txd.phys);
         dump_desc_dbg(ioat, desc);
+        wmb();
+        ioat->head += 1;
         __ioat2_issue_pending(ioat);
 }
 
 static void ioat2_start_null_desc(struct ioat2_dma_chan *ioat)
 {
-        spin_lock_bh(&ioat->ring_lock);
+        spin_lock_bh(&ioat->prep_lock);
         __ioat2_start_null_desc(ioat);
-        spin_unlock_bh(&ioat->ring_lock);
+        spin_unlock_bh(&ioat->prep_lock);
 }
 
 static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
@@ -133,15 +132,16 @@ static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
         struct ioat_ring_ent *desc;
         bool seen_current = false;
         u16 active;
-        int i;
+        int idx = ioat->tail, i;
 
         dev_dbg(to_dev(chan), "%s: head: %#x tail: %#x issued: %#x\n",
                 __func__, ioat->head, ioat->tail, ioat->issued);
 
         active = ioat2_ring_active(ioat);
         for (i = 0; i < active && !seen_current; i++) {
-                prefetch(ioat2_get_ring_ent(ioat, ioat->tail + i + 1));
-                desc = ioat2_get_ring_ent(ioat, ioat->tail + i);
+                smp_read_barrier_depends();
+                prefetch(ioat2_get_ring_ent(ioat, idx + i + 1));
+                desc = ioat2_get_ring_ent(ioat, idx + i);
                 tx = &desc->txd;
                 dump_desc_dbg(ioat, desc);
                 if (tx->cookie) {
@@ -157,11 +157,12 @@ static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
                 if (tx->phys == phys_complete)
                         seen_current = true;
         }
-        ioat->tail += i;
+        smp_mb(); /* finish all descriptor reads before incrementing tail */
+        ioat->tail = idx + i;
         BUG_ON(active && !seen_current); /* no active descs have written a completion? */
 
         chan->last_completion = phys_complete;
-        if (ioat->head == ioat->tail) {
+        if (active - i == 0) {
                 dev_dbg(to_dev(chan), "%s: cancel completion timeout\n",
                         __func__);
                 clear_bit(IOAT_COMPLETION_PENDING, &chan->state);
@@ -178,24 +179,9 @@ static void ioat2_cleanup(struct ioat2_dma_chan *ioat)
         struct ioat_chan_common *chan = &ioat->base;
         unsigned long phys_complete;
 
-        prefetch(chan->completion);
-
-        if (!spin_trylock_bh(&chan->cleanup_lock))
-                return;
-
-        if (!ioat_cleanup_preamble(chan, &phys_complete)) {
-                spin_unlock_bh(&chan->cleanup_lock);
-                return;
-        }
-
-        if (!spin_trylock_bh(&ioat->ring_lock)) {
-                spin_unlock_bh(&chan->cleanup_lock);
-                return;
-        }
-
-        __cleanup(ioat, phys_complete);
-
-        spin_unlock_bh(&ioat->ring_lock);
+        spin_lock_bh(&chan->cleanup_lock);
+        if (ioat_cleanup_preamble(chan, &phys_complete))
+                __cleanup(ioat, phys_complete);
         spin_unlock_bh(&chan->cleanup_lock);
 }
 
@@ -286,12 +272,10 @@ void ioat2_timer_event(unsigned long data)
         struct ioat2_dma_chan *ioat = to_ioat2_chan((void *) data);
         struct ioat_chan_common *chan = &ioat->base;
 
-        spin_lock_bh(&chan->cleanup_lock);
         if (test_bit(IOAT_COMPLETION_PENDING, &chan->state)) {
                 unsigned long phys_complete;
                 u64 status;
 
-                spin_lock_bh(&ioat->ring_lock);
                 status = ioat_chansts(chan);
 
                 /* when halted due to errors check for channel
@@ -310,26 +294,31 @@ void ioat2_timer_event(unsigned long data)
                  * acknowledged a pending completion once, then be more
                  * forceful with a restart
                  */
-                if (ioat_cleanup_preamble(chan, &phys_complete))
+                spin_lock_bh(&chan->cleanup_lock);
+                if (ioat_cleanup_preamble(chan, &phys_complete)) {
                         __cleanup(ioat, phys_complete);
-                else if (test_bit(IOAT_COMPLETION_ACK, &chan->state))
+                } else if (test_bit(IOAT_COMPLETION_ACK, &chan->state)) {
+                        spin_lock_bh(&ioat->prep_lock);
                         ioat2_restart_channel(ioat);
-                else {
+                        spin_unlock_bh(&ioat->prep_lock);
+                } else {
                         set_bit(IOAT_COMPLETION_ACK, &chan->state);
                         mod_timer(&chan->timer, jiffies + COMPLETION_TIMEOUT);
                 }
-                spin_unlock_bh(&ioat->ring_lock);
+                spin_unlock_bh(&chan->cleanup_lock);
         } else {
                 u16 active;
 
                 /* if the ring is idle, empty, and oversized try to step
                  * down the size
                  */
-                spin_lock_bh(&ioat->ring_lock);
+                spin_lock_bh(&chan->cleanup_lock);
+                spin_lock_bh(&ioat->prep_lock);
                 active = ioat2_ring_active(ioat);
                 if (active == 0 && ioat->alloc_order > ioat_get_alloc_order())
                         reshape_ring(ioat, ioat->alloc_order-1);
-                spin_unlock_bh(&ioat->ring_lock);
+                spin_unlock_bh(&ioat->prep_lock);
+                spin_unlock_bh(&chan->cleanup_lock);
 
                 /* keep shrinking until we get back to our minimum
                  * default size
@@ -337,7 +326,6 @@ void ioat2_timer_event(unsigned long data)
                 if (ioat->alloc_order > ioat_get_alloc_order())
                         mod_timer(&chan->timer, jiffies + IDLE_TIMEOUT);
         }
-        spin_unlock_bh(&chan->cleanup_lock);
 }
 
 static int ioat2_reset_hw(struct ioat_chan_common *chan)
@@ -391,7 +379,7 @@ int ioat2_enumerate_channels(struct ioatdma_device *device)
 
                 ioat_init_channel(device, &ioat->base, i);
                 ioat->xfercap_log = xfercap_log;
-                spin_lock_init(&ioat->ring_lock);
+                spin_lock_init(&ioat->prep_lock);
                 if (device->reset_hw(&ioat->base)) {
                         i = 0;
                         break;
@@ -417,8 +405,17 @@ static dma_cookie_t ioat2_tx_submit_unlock(struct dma_async_tx_descriptor *tx)
 
         if (!test_and_set_bit(IOAT_COMPLETION_PENDING, &chan->state))
                 mod_timer(&chan->timer, jiffies + COMPLETION_TIMEOUT);
+
+        /* make descriptor updates visible before advancing ioat->head,
+         * this is purposefully not smp_wmb() since we are also
+         * publishing the descriptor updates to a dma device
+         */
+        wmb();
+
+        ioat->head += ioat->produce;
+
         ioat2_update_pending(ioat);
-        spin_unlock_bh(&ioat->ring_lock);
+        spin_unlock_bh(&ioat->prep_lock);
 
         return cookie;
 }
@@ -530,13 +527,15 @@ int ioat2_alloc_chan_resources(struct dma_chan *c)
         if (!ring)
                 return -ENOMEM;
 
-        spin_lock_bh(&ioat->ring_lock);
+        spin_lock_bh(&chan->cleanup_lock);
+        spin_lock_bh(&ioat->prep_lock);
         ioat->ring = ring;
         ioat->head = 0;
         ioat->issued = 0;
         ioat->tail = 0;
         ioat->alloc_order = order;
-        spin_unlock_bh(&ioat->ring_lock);
+        spin_unlock_bh(&ioat->prep_lock);
+        spin_unlock_bh(&chan->cleanup_lock);
 
         tasklet_enable(&chan->cleanup_task);
         ioat2_start_null_desc(ioat);
@@ -552,7 +551,7 @@ bool reshape_ring(struct ioat2_dma_chan *ioat, int order)
          */
         struct ioat_chan_common *chan = &ioat->base;
         struct dma_chan *c = &chan->common;
-        const u16 curr_size = ioat2_ring_mask(ioat) + 1;
+        const u16 curr_size = ioat2_ring_size(ioat);
         const u16 active = ioat2_ring_active(ioat);
         const u16 new_size = 1 << order;
         struct ioat_ring_ent **ring;
@@ -652,54 +651,61 @@ bool reshape_ring(struct ioat2_dma_chan *ioat, int order)
 }
 
 /**
- * ioat2_alloc_and_lock - common descriptor alloc boilerplate for ioat2,3 ops
- * @idx: gets starting descriptor index on successful allocation
+ * ioat2_check_space_lock - verify space and grab ring producer lock
  * @ioat: ioat2,3 channel (ring) to operate on
  * @num_descs: allocation length
  */
-int ioat2_alloc_and_lock(u16 *idx, struct ioat2_dma_chan *ioat, int num_descs)
+int ioat2_check_space_lock(struct ioat2_dma_chan *ioat, int num_descs)
 {
         struct ioat_chan_common *chan = &ioat->base;
+        bool retry;
 
-        spin_lock_bh(&ioat->ring_lock);
+ retry:
+        spin_lock_bh(&ioat->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
          * resizing.
          */
-        while (unlikely(ioat2_ring_space(ioat) <= num_descs)) {
-                if (reshape_ring(ioat, ioat->alloc_order + 1) &&
-                    ioat2_ring_space(ioat) > num_descs)
-                                break;
-
-                if (printk_ratelimit())
-                        dev_dbg(to_dev(chan),
-                                "%s: ring full! num_descs: %d (%x:%x:%x)\n",
-                                __func__, num_descs, ioat->head, ioat->tail,
-                                ioat->issued);
-                spin_unlock_bh(&ioat->ring_lock);
-
-                /* progress reclaim in the allocation failure case we
-                 * may be called under bh_disabled so we need to trigger
-                 * the timer event directly
-                 */
-                spin_lock_bh(&chan->cleanup_lock);
-                if (jiffies > chan->timer.expires &&
-                    timer_pending(&chan->timer)) {
-                        struct ioatdma_device *device = chan->device;
-
-                        mod_timer(&chan->timer, jiffies + COMPLETION_TIMEOUT);
-                        spin_unlock_bh(&chan->cleanup_lock);
-                        device->timer_fn((unsigned long) &chan->common);
-                } else
-                        spin_unlock_bh(&chan->cleanup_lock);
-                return -ENOMEM;
+        if (likely(ioat2_ring_space(ioat) > num_descs)) {
+                dev_dbg(to_dev(chan), "%s: num_descs: %d (%x:%x:%x)\n",
+                        __func__, num_descs, ioat->head, ioat->tail, ioat->issued);
+                ioat->produce = num_descs;
+                return 0;  /* with ioat->prep_lock held */
         }
+        retry = test_and_set_bit(IOAT_RESHAPE_PENDING, &chan->state);
+        spin_unlock_bh(&ioat->prep_lock);
 
-        dev_dbg(to_dev(chan), "%s: num_descs: %d (%x:%x:%x)\n",
-                __func__, num_descs, ioat->head, ioat->tail, ioat->issued);
+        /* is another cpu already trying to expand the ring? */
+        if (retry)
+                goto retry;
 
-        *idx = ioat2_desc_alloc(ioat, num_descs);
-        return 0;  /* with ioat->ring_lock held */
+        spin_lock_bh(&chan->cleanup_lock);
+        spin_lock_bh(&ioat->prep_lock);
+        retry = reshape_ring(ioat, ioat->alloc_order + 1);
+        clear_bit(IOAT_RESHAPE_PENDING, &chan->state);
+        spin_unlock_bh(&ioat->prep_lock);
+        spin_unlock_bh(&chan->cleanup_lock);
+
+        /* if we were able to expand the ring retry the allocation */
+        if (retry)
+                goto retry;
+
+        if (printk_ratelimit())
+                dev_dbg(to_dev(chan), "%s: ring full! num_descs: %d (%x:%x:%x)\n",
+                        __func__, num_descs, ioat->head, ioat->tail, ioat->issued);
+
+        /* progress reclaim in the allocation failure case we may be
+         * called under bh_disabled so we need to trigger the timer
+         * event directly
+         */
+        if (jiffies > chan->timer.expires && timer_pending(&chan->timer)) {
+                struct ioatdma_device *device = chan->device;
+
+                mod_timer(&chan->timer, jiffies + COMPLETION_TIMEOUT);
+                device->timer_fn((unsigned long) &chan->common);
+        }
+
+        return -ENOMEM;
 }
 
 struct dma_async_tx_descriptor *
@@ -712,14 +718,11 @@ ioat2_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
         dma_addr_t dst = dma_dest;
         dma_addr_t src = dma_src;
         size_t total_len = len;
-        int num_descs;
-        u16 idx;
-        int i;
+        int num_descs, idx, i;
 
         num_descs = ioat2_xferlen_to_descs(ioat, len);
-        if (likely(num_descs) &&
-            ioat2_alloc_and_lock(&idx, ioat, num_descs) == 0)
-                /* pass */;
+        if (likely(num_descs) && ioat2_check_space_lock(ioat, num_descs) == 0)
+                idx = ioat->head;
         else
                 return NULL;
         i = 0;
@@ -776,7 +779,8 @@ void ioat2_free_chan_resources(struct dma_chan *c)
         device->cleanup_fn((unsigned long) c);
         device->reset_hw(chan);
 
-        spin_lock_bh(&ioat->ring_lock);
+        spin_lock_bh(&chan->cleanup_lock);
+        spin_lock_bh(&ioat->prep_lock);
         descs = ioat2_ring_space(ioat);
         dev_dbg(to_dev(chan), "freeing %d idle descriptors\n", descs);
         for (i = 0; i < descs; i++) {
@@ -799,7 +803,8 @@ void ioat2_free_chan_resources(struct dma_chan *c)
         ioat->alloc_order = 0;
         pci_pool_free(device->completion_pool, chan->completion,
                       chan->completion_dma);
-        spin_unlock_bh(&ioat->ring_lock);
+        spin_unlock_bh(&ioat->prep_lock);
+        spin_unlock_bh(&chan->cleanup_lock);
 
         chan->last_completion = 0;
         chan->completion_dma = 0;