IB/mthca: Add device-specific support for resizing CQs

Add low-level driver support for resizing CQs (both kernel and
userspace) to mthca.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 105 insertions, 27 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_cq.c b/drivers/infiniband/hw/mthca/mthca_cq.c
index 78d9cc119f33..76aabc5bf371 100644
--- a/drivers/infiniband/hw/mthca/mthca_cq.c
+++ b/drivers/infiniband/hw/mthca/mthca_cq.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
- * Copyright (c) 2005 Cisco Systems, Inc. All rights reserved.
+ * Copyright (c) 2005, 2006 Cisco Systems, Inc. All rights reserved.
  * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
  * Copyright (c) 2004 Voltaire, Inc. All rights reserved.
  *
@@ -150,24 +150,29 @@ struct mthca_err_cqe {
 #define MTHCA_ARBEL_CQ_DB_REQ_NOT      (2 << 24)
 #define MTHCA_ARBEL_CQ_DB_REQ_NOT_MULT (3 << 24)
 
-static inline struct mthca_cqe *get_cqe(struct mthca_cq *cq, int entry)
+static inline struct mthca_cqe *get_cqe_from_buf(struct mthca_cq_buf *buf,
+                                                 int entry)
 {
-        if (cq->is_direct)
-                return cq->queue.direct.buf + (entry * MTHCA_CQ_ENTRY_SIZE);
+        if (buf->is_direct)
+                return buf->queue.direct.buf + (entry * MTHCA_CQ_ENTRY_SIZE);
         else
-                return cq->queue.page_list[entry * MTHCA_CQ_ENTRY_SIZE / PAGE_SIZE].buf
+                return buf->queue.page_list[entry * MTHCA_CQ_ENTRY_SIZE / PAGE_SIZE].buf
                         + (entry * MTHCA_CQ_ENTRY_SIZE) % PAGE_SIZE;
 }
 
-static inline struct mthca_cqe *cqe_sw(struct mthca_cq *cq, int i)
+static inline struct mthca_cqe *get_cqe(struct mthca_cq *cq, int entry)
+{
+        return get_cqe_from_buf(&cq->buf, entry);
+}
+
+static inline struct mthca_cqe *cqe_sw(struct mthca_cqe *cqe)
 {
-        struct mthca_cqe *cqe = get_cqe(cq, i);
         return MTHCA_CQ_ENTRY_OWNER_HW & cqe->owner ? NULL : cqe;
 }
 
 static inline struct mthca_cqe *next_cqe_sw(struct mthca_cq *cq)
 {
-        return cqe_sw(cq, cq->cons_index & cq->ibcq.cqe);
+        return cqe_sw(get_cqe(cq, cq->cons_index & cq->ibcq.cqe));
 }
 
 static inline void set_cqe_hw(struct mthca_cqe *cqe)
@@ -289,7 +294,7 @@ void mthca_cq_clean(struct mthca_dev *dev, u32 cqn, u32 qpn,
          * from our QP and therefore don't need to be checked.
          */
         for (prod_index = cq->cons_index;
-             cqe_sw(cq, prod_index & cq->ibcq.cqe);
+             cqe_sw(get_cqe(cq, prod_index & cq->ibcq.cqe));
              ++prod_index)
                 if (prod_index == cq->cons_index + cq->ibcq.cqe)
                         break;
@@ -324,6 +329,53 @@ void mthca_cq_clean(struct mthca_dev *dev, u32 cqn, u32 qpn,
                 wake_up(&cq->wait);
 }
 
+void mthca_cq_resize_copy_cqes(struct mthca_cq *cq)
+{
+        int i;
+
+        /*
+         * In Tavor mode, the hardware keeps the consumer and producer
+         * indices mod the CQ size.  Since we might be making the CQ
+         * bigger, we need to deal with the case where the producer
+         * index wrapped around before the CQ was resized.
+         */
+        if (!mthca_is_memfree(to_mdev(cq->ibcq.device)) &&
+            cq->ibcq.cqe < cq->resize_buf->cqe) {
+                cq->cons_index &= cq->ibcq.cqe;
+                if (cqe_sw(get_cqe(cq, cq->ibcq.cqe)))
+                        cq->cons_index -= cq->ibcq.cqe + 1;
+        }
+
+        for (i = cq->cons_index; cqe_sw(get_cqe(cq, i & cq->ibcq.cqe)); ++i)
+                memcpy(get_cqe_from_buf(&cq->resize_buf->buf,
+                                        i & cq->resize_buf->cqe),
+                       get_cqe(cq, i & cq->ibcq.cqe), MTHCA_CQ_ENTRY_SIZE);
+}
+
+int mthca_alloc_cq_buf(struct mthca_dev *dev, struct mthca_cq_buf *buf, int nent)
+{
+        int ret;
+        int i;
+
+        ret = mthca_buf_alloc(dev, nent * MTHCA_CQ_ENTRY_SIZE,
+                              MTHCA_MAX_DIRECT_CQ_SIZE,
+                              &buf->queue, &buf->is_direct,
+                              &dev->driver_pd, 1, &buf->mr);
+        if (ret)
+                return ret;
+
+        for (i = 0; i < nent; ++i)
+                set_cqe_hw(get_cqe_from_buf(buf, i));
+
+        return 0;
+}
+
+void mthca_free_cq_buf(struct mthca_dev *dev, struct mthca_cq_buf *buf, int cqe)
+{
+        mthca_buf_free(dev, (cqe + 1) * MTHCA_CQ_ENTRY_SIZE, &buf->queue,
+                       buf->is_direct, &buf->mr);
+}
+
 static void handle_error_cqe(struct mthca_dev *dev, struct mthca_cq *cq,
                              struct mthca_qp *qp, int wqe_index, int is_send,
                              struct mthca_err_cqe *cqe,
@@ -609,11 +661,14 @@ int mthca_poll_cq(struct ib_cq *ibcq, int num_entries,
 
         spin_lock_irqsave(&cq->lock, flags);
 
-        for (npolled = 0; npolled < num_entries; ++npolled) {
+        npolled = 0;
+repoll:
+        while (npolled < num_entries) {
                 err = mthca_poll_one(dev, cq, &qp,
                                      &freed, entry + npolled);
                 if (err)
                         break;
+                ++npolled;
         }
 
         if (freed) {
@@ -621,6 +676,42 @@ int mthca_poll_cq(struct ib_cq *ibcq, int num_entries,
                 update_cons_index(dev, cq, freed);
         }
 
+        /*
+         * If a CQ resize is in progress and we discovered that the
+         * old buffer is empty, then peek in the new buffer, and if
+         * it's not empty, switch to the new buffer and continue
+         * polling there.
+         */
+        if (unlikely(err == -EAGAIN && cq->resize_buf &&
+                     cq->resize_buf->state == CQ_RESIZE_READY)) {
+                /*
+                 * In Tavor mode, the hardware keeps the producer
+                 * index modulo the CQ size.  Since we might be making
+                 * the CQ bigger, we need to mask our consumer index
+                 * using the size of the old CQ buffer before looking
+                 * in the new CQ buffer.
+                 */
+                if (!mthca_is_memfree(dev))
+                        cq->cons_index &= cq->ibcq.cqe;
+
+                if (cqe_sw(get_cqe_from_buf(&cq->resize_buf->buf,
+                                            cq->cons_index & cq->resize_buf->cqe))) {
+                        struct mthca_cq_buf tbuf;
+                        int tcqe;
+
+                        tbuf         = cq->buf;
+                        tcqe         = cq->ibcq.cqe;
+                        cq->buf      = cq->resize_buf->buf;
+                        cq->ibcq.cqe = cq->resize_buf->cqe;
+
+                        cq->resize_buf->buf   = tbuf;
+                        cq->resize_buf->cqe   = tcqe;
+                        cq->resize_buf->state = CQ_RESIZE_SWAPPED;
+
+                        goto repoll;
+                }
+        }
+
         spin_unlock_irqrestore(&cq->lock, flags);
 
         return err == 0 || err == -EAGAIN ? npolled : err;
@@ -679,22 +770,14 @@ int mthca_arbel_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify notify)
         return 0;
 }
 
-static void mthca_free_cq_buf(struct mthca_dev *dev, struct mthca_cq *cq)
-{
-        mthca_buf_free(dev, (cq->ibcq.cqe + 1) * MTHCA_CQ_ENTRY_SIZE,
-                       &cq->queue, cq->is_direct, &cq->mr);
-}
-
 int mthca_init_cq(struct mthca_dev *dev, int nent,
                   struct mthca_ucontext *ctx, u32 pdn,
                   struct mthca_cq *cq)
 {
-        int size = nent * MTHCA_CQ_ENTRY_SIZE;
         struct mthca_mailbox *mailbox;
         struct mthca_cq_context *cq_context;
         int err = -ENOMEM;
         u8 status;
-        int i;
 
         cq->ibcq.cqe  = nent - 1;
         cq->is_kernel = !ctx;
@@ -732,14 +815,9 @@ int mthca_init_cq(struct mthca_dev *dev, int nent,
         cq_context = mailbox->buf;
 
         if (cq->is_kernel) {
-                err = mthca_buf_alloc(dev, size, MTHCA_MAX_DIRECT_CQ_SIZE,
-                                      &cq->queue, &cq->is_direct,
-                                      &dev->driver_pd, 1, &cq->mr);
+                err = mthca_alloc_cq_buf(dev, &cq->buf, nent);
                 if (err)
                         goto err_out_mailbox;
-
-                for (i = 0; i < nent; ++i)
-                        set_cqe_hw(get_cqe(cq, i));
         }
 
         spin_lock_init(&cq->lock);
@@ -758,7 +836,7 @@ int mthca_init_cq(struct mthca_dev *dev, int nent,
         cq_context->error_eqn       = cpu_to_be32(dev->eq_table.eq[MTHCA_EQ_ASYNC].eqn);
         cq_context->comp_eqn        = cpu_to_be32(dev->eq_table.eq[MTHCA_EQ_COMP].eqn);
         cq_context->pd              = cpu_to_be32(pdn);
-        cq_context->lkey            = cpu_to_be32(cq->mr.ibmr.lkey);
+        cq_context->lkey            = cpu_to_be32(cq->buf.mr.ibmr.lkey);
         cq_context->cqn             = cpu_to_be32(cq->cqn);
 
         if (mthca_is_memfree(dev)) {
@@ -796,7 +874,7 @@ int mthca_init_cq(struct mthca_dev *dev, int nent,
 
 err_out_free_mr:
         if (cq->is_kernel)
-                mthca_free_cq_buf(dev, cq);
+                mthca_free_cq_buf(dev, &cq->buf, cq->ibcq.cqe);
 
 err_out_mailbox:
         mthca_free_mailbox(dev, mailbox);
@@ -862,7 +940,7 @@ void mthca_free_cq(struct mthca_dev *dev,
         wait_event(cq->wait, !atomic_read(&cq->refcount));
 
         if (cq->is_kernel) {
-                mthca_free_cq_buf(dev, cq);
+                mthca_free_cq_buf(dev, &cq->buf, cq->ibcq.cqe);
                 if (mthca_is_memfree(dev)) {
                         mthca_free_db(dev, MTHCA_DB_TYPE_CQ_ARM,    cq->arm_db_index);
                         mthca_free_db(dev, MTHCA_DB_TYPE_CQ_SET_CI, cq->set_ci_db_index);