[PATCH] IB/mthca: fix MTT allocation in mem-free mode

Fix bug in MTT allocation in mem-free mode.

I misunderstood the MTT size value returned by the firmware -- it is really
the size of a single MTT entry, since mem-free mode does not segment the MTT
as the original firmware did.  This meant that our MTT addresses ended up
being off by a factor of 8.  This meant that our MTT allocations might
overlap, and so we could overwrite and corrupt earlier memory regions when
writing new MTT entries.

We fix this by always using our 64-byte MTT segment size.  This allows some
simplification of the code as well, since there's no reason to put the MTT
segment size in a variable -- we can always use our enum value directly.

Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

6 files changed, 6 insertions, 11 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_cmd.c b/drivers/infiniband/hw/mthca/mthca_cmd.c
index 1bc1ce75816..244d37c5bf6 100644
--- a/drivers/infiniband/hw/mthca/mthca_cmd.c
+++ b/drivers/infiniband/hw/mthca/mthca_cmd.c
@@ -990,7 +990,6 @@ int mthca_QUERY_DEV_LIM(struct mthca_dev *dev,
 		MTHCA_GET(field, outbox, QUERY_DEV_LIM_MAX_SG_RQ_OFFSET);
 		dev_lim->max_sg = min_t(int, field, dev_lim->max_sg);
 		MTHCA_GET(size, outbox, QUERY_DEV_LIM_MTT_ENTRY_SZ_OFFSET);
-		dev_lim->mtt_seg_sz = size;
 		MTHCA_GET(size, outbox, QUERY_DEV_LIM_MPT_ENTRY_SZ_OFFSET);
 		dev_lim->mpt_entry_sz = size;
 		MTHCA_GET(field, outbox, QUERY_DEV_LIM_PBL_SZ_OFFSET);
@@ -1018,7 +1017,6 @@ int mthca_QUERY_DEV_LIM(struct mthca_dev *dev,
 	} else {
 		MTHCA_GET(field, outbox, QUERY_DEV_LIM_MAX_AV_OFFSET);
 		dev_lim->hca.tavor.max_avs = 1 << (field & 0x3f);
-		dev_lim->mtt_seg_sz   = MTHCA_MTT_SEG_SIZE;
 		dev_lim->mpt_entry_sz = MTHCA_MPT_ENTRY_SIZE;
 	}
 
diff --git a/drivers/infiniband/hw/mthca/mthca_cmd.h b/drivers/infiniband/hw/mthca/mthca_cmd.h
index a8bc6aa36ff..a6da34dce8e 100644
--- a/drivers/infiniband/hw/mthca/mthca_cmd.h
+++ b/drivers/infiniband/hw/mthca/mthca_cmd.h
@@ -162,7 +162,6 @@ struct mthca_dev_lim {
 	int cqc_entry_sz;
 	int srq_entry_sz;
 	int uar_scratch_entry_sz;
-	int mtt_seg_sz;
 	int mpt_entry_sz;
 	union {
 		struct {
diff --git a/drivers/infiniband/hw/mthca/mthca_dev.h b/drivers/infiniband/hw/mthca/mthca_dev.h
index 56b2bfb5adb..f437979e896 100644
--- a/drivers/infiniband/hw/mthca/mthca_dev.h
+++ b/drivers/infiniband/hw/mthca/mthca_dev.h
@@ -121,7 +121,6 @@ struct mthca_limits {
 	int      reserved_eqs;
 	int      num_mpts;
 	int      num_mtt_segs;
-	int      mtt_seg_size;
 	int      reserved_mtts;
 	int      reserved_mrws;
 	int      reserved_uars;
diff --git a/drivers/infiniband/hw/mthca/mthca_main.c b/drivers/infiniband/hw/mthca/mthca_main.c
index 144aed417fa..7912b262a4c 100644
--- a/drivers/infiniband/hw/mthca/mthca_main.c
+++ b/drivers/infiniband/hw/mthca/mthca_main.c
@@ -390,7 +390,7 @@ static int __devinit mthca_init_icm(struct mthca_dev *mdev,
 	}
 
 	mdev->mr_table.mtt_table = mthca_alloc_icm_table(mdev, init_hca->mtt_base,
-							 dev_lim->mtt_seg_sz,
+							 MTHCA_MTT_SEG_SIZE,
 							 mdev->limits.num_mtt_segs,
 							 mdev->limits.reserved_mtts, 1);
 	if (!mdev->mr_table.mtt_table) {
diff --git a/drivers/infiniband/hw/mthca/mthca_mr.c b/drivers/infiniband/hw/mthca/mthca_mr.c
index 66656379ea7..5cde296b406 100644
--- a/drivers/infiniband/hw/mthca/mthca_mr.c
+++ b/drivers/infiniband/hw/mthca/mthca_mr.c
@@ -263,7 +263,7 @@ int mthca_mr_alloc_phys(struct mthca_dev *dev, u32 pd,
 			goto err_out_mpt_free;
 	}
 
-	for (i = dev->limits.mtt_seg_size / 8, mr->order = 0;
+	for (i = MTHCA_MTT_SEG_SIZE / 8, mr->order = 0;
 	     i < list_len;
 	     i <<= 1, ++mr->order)
 		; /* nothing */
@@ -286,7 +286,7 @@ int mthca_mr_alloc_phys(struct mthca_dev *dev, u32 pd,
 	mtt_entry = MAILBOX_ALIGN(mailbox);
 
 	mtt_entry[0] = cpu_to_be64(dev->mr_table.mtt_base +
-				   mr->first_seg * dev->limits.mtt_seg_size);
+				   mr->first_seg * MTHCA_MTT_SEG_SIZE);
 	mtt_entry[1] = 0;
 	for (i = 0; i < list_len; ++i)
 		mtt_entry[i + 2] = cpu_to_be64(buffer_list[i] |
@@ -330,7 +330,7 @@ int mthca_mr_alloc_phys(struct mthca_dev *dev, u32 pd,
 	memset(&mpt_entry->lkey, 0,
 	       sizeof *mpt_entry - offsetof(struct mthca_mpt_entry, lkey));
 	mpt_entry->mtt_seg   = cpu_to_be64(dev->mr_table.mtt_base +
-					   mr->first_seg * dev->limits.mtt_seg_size);
+					   mr->first_seg * MTHCA_MTT_SEG_SIZE);
 
 	if (0) {
 		mthca_dbg(dev, "Dumping MPT entry %08x:\n", mr->ibmr.lkey);
diff --git a/drivers/infiniband/hw/mthca/mthca_profile.c b/drivers/infiniband/hw/mthca/mthca_profile.c
index 9ffe76e23a9..cfd6f70c8df 100644
--- a/drivers/infiniband/hw/mthca/mthca_profile.c
+++ b/drivers/infiniband/hw/mthca/mthca_profile.c
@@ -95,7 +95,7 @@ u64 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  = dev_lim->mtt_seg_sz;
+	profile[MTHCA_RES_MTT].size  = MTHCA_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;
@@ -229,10 +229,9 @@ u64 mthca_make_profile(struct mthca_dev *dev,
 			break;
 		case MTHCA_RES_MTT:
 			dev->limits.num_mtt_segs = profile[i].num;
-			dev->limits.mtt_seg_size = dev_lim->mtt_seg_sz;
 			dev->mr_table.mtt_base   = profile[i].start;
 			init_hca->mtt_base       = profile[i].start;
-			init_hca->mtt_seg_sz     = ffs(dev_lim->mtt_seg_sz) - 7;
+			init_hca->mtt_seg_sz     = ffs(MTHCA_MTT_SEG_SIZE) - 7;
 			break;
 		case MTHCA_RES_UAR:
 			dev->limits.num_uars       = profile[i].num;