IB/mthca: Add module parameter for number of MTTs per segment

The current MTT allocator uses kmalloc() to allocate a buffer for its
buddy allocator, and thus is limited in the amount of MTT segments
that it can control.  As a result, the size of memory that can be
registered is limited too.  This patch uses a module parameter to
control the number of MTT entries that each segment represents,
allowing more memory to be registered with the same number of
segments.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

5 files changed, 26 insertions, 14 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_cmd.c b/drivers/infiniband/hw/mthca/mthca_cmd.c
index 6d55f9d748f6..8c2ed994d540 100644
--- a/drivers/infiniband/hw/mthca/mthca_cmd.c
+++ b/drivers/infiniband/hw/mthca/mthca_cmd.c
@@ -1059,7 +1059,7 @@ int mthca_QUERY_DEV_LIM(struct mthca_dev *dev,
         MTHCA_GET(field, outbox, QUERY_DEV_LIM_RSVD_MTT_OFFSET);
         if (mthca_is_memfree(dev))
                 dev_lim->reserved_mtts = ALIGN((1 << (field >> 4)) * sizeof(u64),
-                                               MTHCA_MTT_SEG_SIZE) / MTHCA_MTT_SEG_SIZE;
+                                               dev->limits.mtt_seg_size) / dev->limits.mtt_seg_size;
         else
                 dev_lim->reserved_mtts = 1 << (field >> 4);
         MTHCA_GET(field, outbox, QUERY_DEV_LIM_MAX_MRW_SZ_OFFSET);
diff --git a/drivers/infiniband/hw/mthca/mthca_dev.h b/drivers/infiniband/hw/mthca/mthca_dev.h
index 252590116df5..9ef611f6dd36 100644
--- a/drivers/infiniband/hw/mthca/mthca_dev.h
+++ b/drivers/infiniband/hw/mthca/mthca_dev.h
@@ -159,6 +159,7 @@ struct mthca_limits {
         int      reserved_eqs;
         int      num_mpts;
         int      num_mtt_segs;
+        int      mtt_seg_size;
         int      fmr_reserved_mtts;
         int      reserved_mtts;
         int      reserved_mrws;
diff --git a/drivers/infiniband/hw/mthca/mthca_main.c b/drivers/infiniband/hw/mthca/mthca_main.c
index 1d83cf7caf38..13da9f1d24c0 100644
--- a/drivers/infiniband/hw/mthca/mthca_main.c
+++ b/drivers/infiniband/hw/mthca/mthca_main.c
@@ -125,6 +125,10 @@ module_param_named(fmr_reserved_mtts, hca_profile.fmr_reserved_mtts, int, 0444);
 MODULE_PARM_DESC(fmr_reserved_mtts,
                  "number of memory translation table segments reserved for FMR");
 
+static int log_mtts_per_seg = ilog2(MTHCA_MTT_SEG_SIZE / 8);
+module_param_named(log_mtts_per_seg, log_mtts_per_seg, int, 0444);
+MODULE_PARM_DESC(log_mtts_per_seg, "Log2 number of MTT entries per segment (1-5)");
+
 static char mthca_version[] __devinitdata =
         DRV_NAME ": Mellanox InfiniBand HCA driver v"
         DRV_VERSION " (" DRV_RELDATE ")\n";
@@ -162,6 +166,7 @@ static int mthca_dev_lim(struct mthca_dev *mdev, struct mthca_dev_lim *dev_lim)
         int err;
         u8 status;
 
+        mdev->limits.mtt_seg_size = (1 << log_mtts_per_seg) * 8;
         err = mthca_QUERY_DEV_LIM(mdev, dev_lim, &status);
         if (err) {
                 mthca_err(mdev, "QUERY_DEV_LIM command failed, aborting.\n");
@@ -460,11 +465,11 @@ static int mthca_init_icm(struct mthca_dev *mdev,
         }
 
         /* CPU writes to non-reserved MTTs, while HCA might DMA to reserved mtts */
-        mdev->limits.reserved_mtts = ALIGN(mdev->limits.reserved_mtts * MTHCA_MTT_SEG_SIZE,
-                                           dma_get_cache_alignment()) / MTHCA_MTT_SEG_SIZE;
+        mdev->limits.reserved_mtts = ALIGN(mdev->limits.reserved_mtts * mdev->limits.mtt_seg_size,
+                                           dma_get_cache_alignment()) / mdev->limits.mtt_seg_size;
 
         mdev->mr_table.mtt_table = mthca_alloc_icm_table(mdev, init_hca->mtt_base,
-                                                         MTHCA_MTT_SEG_SIZE,
+                                                         mdev->limits.mtt_seg_size,
                                                          mdev->limits.num_mtt_segs,
                                                          mdev->limits.reserved_mtts,
                                                          1, 0);
@@ -1315,6 +1320,12 @@ static void __init mthca_validate_profile(void)
                 printk(KERN_WARNING PFX "Corrected fmr_reserved_mtts to %d.\n",
                        hca_profile.fmr_reserved_mtts);
         }
+
+        if ((log_mtts_per_seg < 1) || (log_mtts_per_seg > 5)) {
+                printk(KERN_WARNING PFX "bad log_mtts_per_seg (%d). Using default - %d\n",
+                       log_mtts_per_seg, ilog2(MTHCA_MTT_SEG_SIZE / 8));
+                log_mtts_per_seg = ilog2(MTHCA_MTT_SEG_SIZE / 8);
+        }
 }
 
 static int __init mthca_init(void)
diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c b/drivers/infiniband/hw/mthca/mthca_mr.c
index 882e6b735915..d606edf10858 100644
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -220,7 +220,7 @@ static struct mthca_mtt *__mthca_alloc_mtt(struct mthca_dev *dev, int size,
 
         mtt->buddy = buddy;
         mtt->order = 0;
-        for (i = MTHCA_MTT_SEG_SIZE / 8; i < size; i <<= 1)
+        for (i = dev->limits.mtt_seg_size / 8; i < size; i <<= 1)
                 ++mtt->order;
 
         mtt->first_seg = mthca_alloc_mtt_range(dev, mtt->order, buddy);
@@ -267,7 +267,7 @@ static int __mthca_write_mtt(struct mthca_dev *dev, struct mthca_mtt *mtt,
 
         while (list_len > 0) {
                 mtt_entry[0] = cpu_to_be64(dev->mr_table.mtt_base +
-                                           mtt->first_seg * MTHCA_MTT_SEG_SIZE +
+                                           mtt->first_seg * dev->limits.mtt_seg_size +
                                            start_index * 8);
                 mtt_entry[1] = 0;
                 for (i = 0; i < list_len && i < MTHCA_MAILBOX_SIZE / 8 - 2; ++i)
@@ -326,7 +326,7 @@ static void mthca_tavor_write_mtt_seg(struct mthca_dev *dev,
         u64 __iomem *mtts;
         int i;
 
-        mtts = dev->mr_table.tavor_fmr.mtt_base + mtt->first_seg * MTHCA_MTT_SEG_SIZE +
+        mtts = dev->mr_table.tavor_fmr.mtt_base + mtt->first_seg * dev->limits.mtt_seg_size +
                 start_index * sizeof (u64);
         for (i = 0; i < list_len; ++i)
                 mthca_write64_raw(cpu_to_be64(buffer_list[i] | MTHCA_MTT_FLAG_PRESENT),
@@ -345,10 +345,10 @@ static void mthca_arbel_write_mtt_seg(struct mthca_dev *dev,
         /* For Arbel, all MTTs must fit in the same page. */
         BUG_ON(s / PAGE_SIZE != (s + list_len * sizeof(u64) - 1) / PAGE_SIZE);
         /* Require full segments */
-        BUG_ON(s % MTHCA_MTT_SEG_SIZE);
+        BUG_ON(s % dev->limits.mtt_seg_size);
 
         mtts = mthca_table_find(dev->mr_table.mtt_table, mtt->first_seg +
-                                s / MTHCA_MTT_SEG_SIZE, &dma_handle);
+                                s / dev->limits.mtt_seg_size, &dma_handle);
 
         BUG_ON(!mtts);
 
@@ -479,7 +479,7 @@ int mthca_mr_alloc(struct mthca_dev *dev, u32 pd, int buffer_size_shift,
         if (mr->mtt)
                 mpt_entry->mtt_seg =
                         cpu_to_be64(dev->mr_table.mtt_base +
-                                    mr->mtt->first_seg * MTHCA_MTT_SEG_SIZE);
+                                    mr->mtt->first_seg * dev->limits.mtt_seg_size);
 
         if (0) {
                 mthca_dbg(dev, "Dumping MPT entry %08x:\n", mr->ibmr.lkey);
@@ -626,7 +626,7 @@ int mthca_fmr_alloc(struct mthca_dev *dev, u32 pd,
                 goto err_out_table;
         }
 
-        mtt_seg = mr->mtt->first_seg * MTHCA_MTT_SEG_SIZE;
+        mtt_seg = mr->mtt->first_seg * dev->limits.mtt_seg_size;
 
         if (mthca_is_memfree(dev)) {
                 mr->mem.arbel.mtts = mthca_table_find(dev->mr_table.mtt_table,
@@ -908,7 +908,7 @@ int mthca_init_mr_table(struct mthca_dev *dev)
                          dev->mr_table.mtt_base);
 
                 dev->mr_table.tavor_fmr.mtt_base =
-                        ioremap(addr, mtts * MTHCA_MTT_SEG_SIZE);
+                        ioremap(addr, mtts * dev->limits.mtt_seg_size);
                 if (!dev->mr_table.tavor_fmr.mtt_base) {
                         mthca_warn(dev, "MTT ioremap for FMR failed.\n");
                         err = -ENOMEM;
diff --git a/drivers/infiniband/hw/mthca/mthca_profile.c b/drivers/infiniband/hw/mthca/mthca_profile.c
index d168c2540611..8edb28a9a0e7 100644
--- a/drivers/infiniband/hw/mthca/mthca_profile.c
+++ b/drivers/infiniband/hw/mthca/mthca_profile.c
@@ -94,7 +94,7 @@ s64 mthca_make_profile(struct mthca_dev *dev,
         profile[MTHCA_RES_RDB].size  = MTHCA_RDB_ENTRY_SIZE;
         profile[MTHCA_RES_MCG].size  = MTHCA_MGM_ENTRY_SIZE;
         profile[MTHCA_RES_MPT].size  = dev_lim->mpt_entry_sz;
-        profile[MTHCA_RES_MTT].size  = MTHCA_MTT_SEG_SIZE;
+        profile[MTHCA_RES_MTT].size  = dev->limits.mtt_seg_size;
         profile[MTHCA_RES_UAR].size  = dev_lim->uar_scratch_entry_sz;
         profile[MTHCA_RES_UDAV].size = MTHCA_AV_SIZE;
         profile[MTHCA_RES_UARC].size = request->uarc_size;
@@ -232,7 +232,7 @@ s64 mthca_make_profile(struct mthca_dev *dev,
                         dev->limits.num_mtt_segs = profile[i].num;
                         dev->mr_table.mtt_base   = profile[i].start;
                         init_hca->mtt_base       = profile[i].start;
-                        init_hca->mtt_seg_sz     = ffs(MTHCA_MTT_SEG_SIZE) - 7;
+                        init_hca->mtt_seg_sz     = ffs(dev->limits.mtt_seg_size) - 7;
                         break;
                 case MTHCA_RES_UAR:
                         dev->limits.num_uars       = profile[i].num;