From: Jason Gunthorpe <jgg@nvidia.com>
Date: Fri, 5 Jun 2026 11:53:35 +0000 (-0300)
Subject: IB/mlx4: Fill in the access_flags if IB_MR_REREG_ACCESS is not specified
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bade9a3150d44ed20b8c6484c4c8a943b7289abb;p=thirdparty%2Fkernel%2Flinux.git

IB/mlx4: Fill in the access_flags if IB_MR_REREG_ACCESS is not specified

Sashiko noticed mlx4 was using whatever random access flags were provided
when IB_MR_REREG_ACCESS is not used. Since IB_MR_REREG_TRANS needs
access_flags it used the random ones which means it doesn't work sensibly
if userspace provides only IB_MR_REREG_TRANS.

Keep track of the current access_flag of the MR and use it if the user
does not specify one.

Also fixup a little confusion around mmr.access, it is the HW access flags
so the convert_access() was missing. But nothing reads this by the time
rereg_mr can happen.

Fixes: 9376932d0c26 ("IB/mlx4_ib: Add support for user MR re-registration")
Link: https://patch.msgid.link/r/0-v1-29ca7a402625+ddd6-mlx4_rereg_flags_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---

diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h b/drivers/infiniband/hw/mlx4/mlx4_ib.h
index 598954dd0613d..2b6cc011b25d6 100644
--- a/drivers/infiniband/hw/mlx4/mlx4_ib.h
+++ b/drivers/infiniband/hw/mlx4/mlx4_ib.h
@@ -136,6 +136,7 @@ struct mlx4_ib_mr {
 	dma_addr_t		page_map;
 	u32			npages;
 	u32			max_pages;
+	int			access_flags;
 	struct mlx4_mr		mmr;
 	struct ib_umem	       *umem;
 	size_t			page_map_size;
diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index 027ffb6f79d32..906f09a87704e 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -181,6 +181,7 @@ struct ib_mr *mlx4_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (err)
 		goto err_mr;
 
+	mr->access_flags = access_flags;
 	mr->ibmr.rkey = mr->ibmr.lkey = mr->mmr.key;
 	mr->ibmr.page_size = 1U << shift;
 
@@ -237,6 +238,8 @@ struct ib_mr *mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags, u64 start,
 
 		if (err)
 			goto release_mpt_entry;
+	} else {
+		mr_access_flags = mmr->access_flags;
 	}
 
 	if (flags & IB_MR_REREG_TRANS) {
@@ -278,8 +281,10 @@ struct ib_mr *mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags, u64 start,
 	 * return a failure. But dereg_mr will free the resources.
 	 */
 	err = mlx4_mr_hw_write_mpt(dev->dev, &mmr->mmr, pmpt_entry);
-	if (!err && flags & IB_MR_REREG_ACCESS)
-		mmr->mmr.access = mr_access_flags;
+	if (!err && flags & IB_MR_REREG_ACCESS) {
+		mmr->access_flags = mr_access_flags;
+		mmr->mmr.access = convert_access(mr_access_flags);
+	}
 
 release_mpt_entry:
 	mlx4_mr_hw_put_mpt(dev->dev, pmpt_entry);