IB/srp: Work around data corruption bug on Mellanox targets

Data corruption has been seen with Mellanox SRP targets when FMRs
create a memory region with I/O virtual address != 0.  Add a
workaround that disables FMR merging for Mellanox targets (OUI 0002c9).

Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index ff94e4e32691..8257d5a2c8f8 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -77,6 +77,14 @@ MODULE_PARM_DESC(topspin_workarounds,
 
 static const u8 topspin_oui[3] = { 0x00, 0x05, 0xad };
 
+static int mellanox_workarounds = 1;
+
+module_param(mellanox_workarounds, int, 0444);
+MODULE_PARM_DESC(mellanox_workarounds,
+                 "Enable workarounds for Mellanox SRP target bugs if != 0");
+
+static const u8 mellanox_oui[3] = { 0x00, 0x02, 0xc9 };
+
 static void srp_add_one(struct ib_device *device);
 static void srp_remove_one(struct ib_device *device);
 static void srp_completion(struct ib_cq *cq, void *target_ptr);
@@ -569,7 +577,7 @@ err:
         return ret;
 }
 
-static int srp_map_fmr(struct srp_device *dev, struct scatterlist *scat,
+static int srp_map_fmr(struct srp_target_port *target, struct scatterlist *scat,
                        int sg_cnt, struct srp_request *req,
                        struct srp_direct_buf *buf)
 {
@@ -579,10 +587,15 @@ static int srp_map_fmr(struct srp_device *dev, struct scatterlist *scat,
         int page_cnt;
         int i, j;
         int ret;
+        struct srp_device *dev = target->srp_host->dev;
 
         if (!dev->fmr_pool)
                 return -ENODEV;
 
+        if ((sg_dma_address(&scat[0]) & ~dev->fmr_page_mask) &&
+            mellanox_workarounds && !memcmp(&target->ioc_guid, mellanox_oui, 3))
+                return -EINVAL;
+
         len = page_cnt = 0;
         for (i = 0; i < sg_cnt; ++i) {
                 if (sg_dma_address(&scat[i]) & ~dev->fmr_page_mask) {
@@ -685,7 +698,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
                 buf->va  = cpu_to_be64(sg_dma_address(scat));
                 buf->key = cpu_to_be32(target->srp_host->dev->mr->rkey);
                 buf->len = cpu_to_be32(sg_dma_len(scat));
-        } else if (srp_map_fmr(target->srp_host->dev, scat, count, req,
+        } else if (srp_map_fmr(target, scat, count, req,
                                (void *) cmd->add_data)) {
                 /*
                  * FMR mapping failed, and the scatterlist has more