[PATCH 2/2] iw_cxgb4: limit MRs to < 8GB for T4/T5 devices

[Hariprasad Shenai]

T4/T5 hardware can't handle MRs >= 8GB due to a hardware bug.  So limit
registrations to < 8GB for thse devices.

Based on original work by Steve Wise <sw...@opengridcomputing.com>

Signed-off-by: Steve Wise <sw...@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <haripra...@chelsio.com>
---
 drivers/infiniband/hw/cxgb4/mem.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/drivers/infiniband/hw/cxgb4/mem.c 
b/drivers/infiniband/hw/cxgb4/mem.c
index ec7a298..d5dd3f2 100644
--- a/drivers/infiniband/hw/cxgb4/mem.c
+++ b/drivers/infiniband/hw/cxgb4/mem.c
@@ -50,6 +50,13 @@ static int inline_threshold = C4IW_INLINE_THRESHOLD;
 module_param(inline_threshold, int, 0644);
 MODULE_PARM_DESC(inline_threshold, "inline vs dsgl threshold (default=128)");
 
+static int mr_exceeds_hw_limits(struct c4iw_dev *dev, u64 length)
+{
+       return (is_t4(dev->rdev.lldi.adapter_type) ||
+               is_t5(dev->rdev.lldi.adapter_type)) &&
+               length >= 8*1024*1024*1024ULL;
+}
+
 static int _c4iw_write_mem_dma_aligned(struct c4iw_rdev *rdev, u32 addr,
                                       u32 len, dma_addr_t data, int wait)
 {
@@ -536,6 +543,11 @@ int c4iw_reregister_phys_mem(struct ib_mr *mr, int 
mr_rereg_mask,
                        return ret;
        }
 
+       if (mr_exceeds_hw_limits(rhp, total_size)) {
+               kfree(page_list);
+               return -EINVAL;
+       }
+
        ret = reregister_mem(rhp, php, &mh, shift, npages);
        kfree(page_list);
        if (ret)
@@ -596,6 +608,12 @@ struct ib_mr *c4iw_register_phys_mem(struct ib_pd *pd,
        if (ret)
                goto err;
 
+       if (mr_exceeds_hw_limits(rhp, total_size)) {
+               kfree(page_list);
+               ret = -EINVAL;
+               goto err;
+       }
+
        ret = alloc_pbl(mhp, npages);
        if (ret) {
                kfree(page_list);
@@ -699,6 +717,10 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 
start, u64 length,
 
        php = to_c4iw_pd(pd);
        rhp = php->rhp;
+
+       if (mr_exceeds_hw_limits(rhp, length))
+               return ERR_PTR(-EINVAL);
+
        mhp = kzalloc(sizeof(*mhp), GFP_KERNEL);
        if (!mhp)
                return ERR_PTR(-ENOMEM);
-- 
1.7.1

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