[PATCH for-next v3] RDMA/rxe: Remove redundant page presence check

[Daisuke Matsuda <dskmtsd@gmail.com>]

hmm_pfn_to_page() does not return NULL. ib_umem_odp_map_dma_and_lock()
should return an error in case the target pages cannot be mapped until
timeout, so these checks can safely be removed.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>

v2->v3:
  - Move page_offset error check before hmm_pfn_to_page(), as suggested by Zhu

---
 drivers/infiniband/sw/rxe/rxe_odp.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
index dbc5a5600eb7..0846bd972e15 100644
--- a/drivers/infiniband/sw/rxe/rxe_odp.c
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -203,8 +203,6 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
 
 		page = hmm_pfn_to_page(umem_odp->map.pfn_list[idx]);
 		user_va = kmap_local_page(page);
-		if (!user_va)
-			return -EFAULT;
 
 		src = (dir == RXE_TO_MR_OBJ) ? addr : user_va;
 		dest = (dir == RXE_TO_MR_OBJ) ? user_va : addr;
@@ -283,17 +281,15 @@ static enum resp_states rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova,
 		return RESPST_ERR_RKEY_VIOLATION;
 	}
 
-	idx = rxe_odp_iova_to_index(umem_odp, iova);
 	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
-	page = hmm_pfn_to_page(umem_odp->map.pfn_list[idx]);
-	if (!page)
-		return RESPST_ERR_RKEY_VIOLATION;
-
 	if (unlikely(page_offset & 0x7)) {
 		rxe_dbg_mr(mr, "iova not aligned\n");
 		return RESPST_ERR_MISALIGNED_ATOMIC;
 	}
 
+	idx = rxe_odp_iova_to_index(umem_odp, iova);
+	page = hmm_pfn_to_page(umem_odp->map.pfn_list[idx]);
+
 	va = kmap_local_page(page);
 
 	spin_lock_bh(&atomic_ops_lock);
@@ -352,10 +348,6 @@ int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
 		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
 
 		page = hmm_pfn_to_page(umem_odp->map.pfn_list[index]);
-		if (!page) {
-			mutex_unlock(&umem_odp->umem_mutex);
-			return -EFAULT;
-		}
 
 		bytes = min_t(unsigned int, length,
 			      mr_page_size(mr) - page_offset);
@@ -396,12 +388,6 @@ enum resp_states rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
 		return RESPST_ERR_RKEY_VIOLATION;
 
 	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
-	index = rxe_odp_iova_to_index(umem_odp, iova);
-	page = hmm_pfn_to_page(umem_odp->map.pfn_list[index]);
-	if (!page) {
-		mutex_unlock(&umem_odp->umem_mutex);
-		return RESPST_ERR_RKEY_VIOLATION;
-	}
 	/* See IBA A19.4.2 */
 	if (unlikely(page_offset & 0x7)) {
 		mutex_unlock(&umem_odp->umem_mutex);
@@ -409,6 +395,9 @@ enum resp_states rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
 		return RESPST_ERR_MISALIGNED_ATOMIC;
 	}
 
+	index = rxe_odp_iova_to_index(umem_odp, iova);
+	page = hmm_pfn_to_page(umem_odp->map.pfn_list[index]);
+
 	va = kmap_local_page(page);
 	/* Do atomic write after all prior operations have completed */
 	smp_store_release(&va[page_offset >> 3], value);
-- 
2.43.0