From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
The rdma_ucm_event_resp is a different length on 32 and 64 bit compiles.
The kernel requires it to be the expected length or longer so 32 bit
builds running on a 64 bit kernel will not work.
Retain full compat by having all kernels accept a struct with or without
the trailing reserved field.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
---
drivers/infiniband/core/ucma.c | 9 +++++++--
include/uapi/rdma/rdma_user_cm.h | 5 +++++
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 4bb5bed596c9d8..db4190b2ed2741 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -382,7 +382,11 @@ static ssize_t ucma_get_event(struct ucma_file *file, const char __user *inbuf,
struct ucma_event *uevent;
int ret = 0;
- if (out_len < sizeof uevent->resp)
+ /*
+ * Old 32 bit user space does not send the 4 byte padding in the
+ * reserved field. We don't care, allow it to keep working.
+ */
+ if (out_len < sizeof(uevent->resp) - sizeof(uevent->resp.reserved))
return -ENOSPC;
if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
@@ -417,7 +421,8 @@ static ssize_t ucma_get_event(struct ucma_file *file, const char __user *inbuf,
}
if (copy_to_user((void __user *)(unsigned long)cmd.response,
- &uevent->resp, sizeof uevent->resp)) {
+ &uevent->resp,
+ min_t(size_t, out_len, sizeof(uevent->resp)))) {
ret = -EFAULT;
goto done;
}
diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
index c83ef0026079c8..65399c837762f5 100644
--- a/include/uapi/rdma/rdma_user_cm.h
+++ b/include/uapi/rdma/rdma_user_cm.h
@@ -270,10 +270,15 @@ struct rdma_ucm_event_resp {
__u32 id;
__u32 event;
__u32 status;
+ /*
+ * NOTE: This union is not aligned to 8 bytes so none of the union
+ * members may contain a u64 or anything with higher alignment than 4.
+ */
union {
struct rdma_ucm_conn_param conn;
struct rdma_ucm_ud_param ud;
} param;
+ __u32 reserved;
};
/* Option levels */
--
2.16.1
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
