RDMA/efa: Count mmap failures

Add a new stat that counts mmap failures, which might help when debugging
different issues.

Link: https://lore.kernel.org/r/20200420062213.44577-3-galpress@amazon.com
Reviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/efa/efa.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */
 /*
- * Copyright 2018-2019 Amazon.com, Inc. or its affiliates. All rights reserved.
+ * Copyright 2018-2020 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
 #ifndef _EFA_H_
@@ -40,6 +40,7 @@ struct efa_sw_stats {
 	atomic64_t reg_mr_err;
 	atomic64_t alloc_ucontext_err;
 	atomic64_t create_ah_err;
+	atomic64_t mmap_err;
 };
 
 /* Don't use anything other than atomic64 */

drivers/infiniband/hw/efa/efa_verbs.c

@@ -44,7 +44,8 @@ struct efa_user_mmap_entry {
 	op(EFA_CREATE_CQ_ERR, "create_cq_err") \
 	op(EFA_REG_MR_ERR, "reg_mr_err") \
 	op(EFA_ALLOC_UCONTEXT_ERR, "alloc_ucontext_err") \
-	op(EFA_CREATE_AH_ERR, "create_ah_err")
+	op(EFA_CREATE_AH_ERR, "create_ah_err") \
+	op(EFA_MMAP_ERR, "mmap_err")
 
 #define EFA_STATS_ENUM(ename, name) ename,
 #define EFA_STATS_STR(ename, name) [ename] = name,
@@ -1569,6 +1570,7 @@ static int __efa_mmap(struct efa_dev *dev, struct efa_ucontext *ucontext,
 		ibdev_dbg(&dev->ibdev,
 			  "pgoff[%#lx] does not have valid entry\n",
 			  vma->vm_pgoff);
+		atomic64_inc(&dev->stats.sw_stats.mmap_err);
 		return -EINVAL;
 	}
 	entry = to_emmap(rdma_entry);
@@ -1604,12 +1606,14 @@ static int __efa_mmap(struct efa_dev *dev, struct efa_ucontext *ucontext,
 		err = -EINVAL;
 	}
 
-	if (err)
+	if (err) {
 		ibdev_dbg(
 			&dev->ibdev,
 			"Couldn't mmap address[%#llx] length[%#zx] mmap_flag[%d] err[%d]\n",
 			entry->address, rdma_entry->npages * PAGE_SIZE,
 			entry->mmap_flag, err);
+		atomic64_inc(&dev->stats.sw_stats.mmap_err);
+	}
 
 	rdma_user_mmap_entry_put(rdma_entry);
 	return err;
@@ -1758,6 +1762,7 @@ int efa_get_hw_stats(struct ib_device *ibdev, struct rdma_hw_stats *stats,
 	stats->value[EFA_REG_MR_ERR] = atomic64_read(&s->sw_stats.reg_mr_err);
 	stats->value[EFA_ALLOC_UCONTEXT_ERR] = atomic64_read(&s->sw_stats.alloc_ucontext_err);
 	stats->value[EFA_CREATE_AH_ERR] = atomic64_read(&s->sw_stats.create_ah_err);
+	stats->value[EFA_MMAP_ERR] = atomic64_read(&s->sw_stats.mmap_err);
 
 	return ARRAY_SIZE(efa_stats_names);
 }