From: Jason Gunthorpe <jgg@nvidia.com>
To: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
linux-rdma@vger.kernel.org
Cc: Leon Romanovsky <leonro@nvidia.com>,
kernel test robot <lkp@intel.com>,
Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>,
llvm@lists.linux.dev, kbuild-all@lists.01.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] IB/qib: Fix null pointer subtraction compiler warning
Date: Fri, 3 Sep 2021 10:07:28 -0300 [thread overview]
Message-ID: <0-v1-43ae3c759177+65-qib_type_jgg@nvidia.com> (raw)
>> drivers/infiniband/hw/qib/qib_sysfs.c:411:1: warning: performing pointer subtraction with a null pointer has undefined behavior
+[-Wnull-pointer-subtraction]
QIB_DIAGC_ATTR(rc_resends);
^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/infiniband/hw/qib/qib_sysfs.c:408:51: note: expanded from macro 'QIB_DIAGC_ATTR'
.counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \
Use offsetof and accomplish the type check using static_assert.
Fixes: 4a7aaf88c89f ("RDMA/qib: Use attributes for the port sysfs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/infiniband/hw/qib/qib_sysfs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c
index d57e49de6650be..452e2355d24eeb 100644
--- a/drivers/infiniband/hw/qib/qib_sysfs.c
+++ b/drivers/infiniband/hw/qib/qib_sysfs.c
@@ -403,9 +403,11 @@ static ssize_t diagc_attr_store(struct ib_device *ibdev, u32 port_num,
}
#define QIB_DIAGC_ATTR(N) \
+ static_assert(&((struct qib_ibport *)0)->rvp.n_##N != (u64 *)NULL); \
static struct qib_diagc_attr qib_diagc_attr_##N = { \
.attr = __ATTR(N, 0664, diagc_attr_show, diagc_attr_store), \
- .counter = &((struct qib_ibport *)0)->rvp.n_##N - (u64 *)0, \
+ .counter = \
+ offsetof(struct qib_ibport, rvp.n_##N) / sizeof(u64) \
}
QIB_DIAGC_ATTR(rc_resends);
base-commit: 6a217437f9f5482a3f6f2dc5fcd27cf0f62409ac
--
2.33.0
next reply other threads:[~2021-09-03 13:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-03 13:07 Jason Gunthorpe [this message]
2021-09-03 17:24 ` Dennis Dalessandro
2021-09-08 11:44 ` Jason Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0-v1-43ae3c759177+65-qib_type_jgg@nvidia.com \
--to=jgg@nvidia.com \
--cc=dennis.dalessandro@cornelisnetworks.com \
--cc=kbuild-all@lists.01.org \
--cc=leonro@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=lkp@intel.com \
--cc=llvm@lists.linux.dev \
--cc=mike.marciniszyn@cornelisnetworks.com \
--subject='Re: [PATCH] IB/qib: Fix null pointer subtraction compiler warning' \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).