From: Jason Gunthorpe <jgg@nvidia.com>
Date: Tue, 3 Mar 2026 19:49:58 +0000 (-0400)
Subject: RDMA: Use copy_struct_from_user() instead of open coding
X-Git-Tag: v7.1-rc1~75^2~77
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=38a6e5579d0d9b9ecc742bad4260a6e90d128e07;p=thirdparty%2Fkernel%2Flinux.git

RDMA: Use copy_struct_from_user() instead of open coding

This entire function is just open coding copy_struct_from_user(), call it
directly, it is faster anyhow.

Link: https://patch.msgid.link/r/1-v3-bd56dd443069+49-bnxt_re_uapi_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 0bfb16cbc6fa..f31650ef7bc3 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -83,28 +83,16 @@ static int uverbs_response(struct uverbs_attr_bundle *attrs, const void *resp,
 	return 0;
 }
 
-/*
- * Copy a request from userspace. If the provided 'req' is larger than the
- * user buffer then the user buffer is zero extended into the 'req'. If 'req'
- * is smaller than the user buffer then the uncopied bytes in the user buffer
- * must be zero.
- */
 static int uverbs_request(struct uverbs_attr_bundle *attrs, void *req,
 			  size_t req_len)
 {
-	if (copy_from_user(req, attrs->ucore.inbuf,
-			   min(attrs->ucore.inlen, req_len)))
-		return -EFAULT;
+	int ret;
 
-	if (attrs->ucore.inlen < req_len) {
-		memset(req + attrs->ucore.inlen, 0,
-		       req_len - attrs->ucore.inlen);
-	} else if (attrs->ucore.inlen > req_len) {
-		if (!ib_is_buffer_cleared(attrs->ucore.inbuf + req_len,
-					  attrs->ucore.inlen - req_len))
-			return -EOPNOTSUPP;
-	}
-	return 0;
+	ret = copy_struct_from_user(req, req_len, attrs->ucore.inbuf,
+				    attrs->ucore.inlen);
+	if (ret == -E2BIG)
+		ret = -EOPNOTSUPP;
+	return ret;
 }
 
 /*