linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Michal Kubecek <mkubecek@suse.cz>
To: Saeed Mahameed <saeedm@mellanox.com>, Leon Romanovsky <leon@kernel.org>
Cc: Alex Vesker <valex@mellanox.com>, Borislav Petkov <bp@alien8.de>,
	Stephen Hemminger <stephen@networkplumber.org>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH net] mlx5: avoid 64-bit division in dr_icm_pool_mr_create()
Date: Wed,  2 Oct 2019 14:12:41 +0200 (CEST)	[thread overview]
Message-ID: <20191002121241.D74DAE04C7@unicorn.suse.cz> (raw)

Recently added code introduces 64-bit division in dr_icm_pool_mr_create()
so that build on 32-bit architectures fails with

  ERROR: "__umoddi3" [drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.ko] undefined!

As the divisor is always a power of 2, we can use bitwise operation
instead.

Fixes: 29cf8febd185 ("net/mlx5: DR, ICM pool memory allocator")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
---
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c
index 913f1e5aaaf2..d7c7467e2d53 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c
@@ -137,7 +137,8 @@ dr_icm_pool_mr_create(struct mlx5dr_icm_pool *pool,
 
 	icm_mr->icm_start_addr = icm_mr->dm.addr;
 
-	align_diff = icm_mr->icm_start_addr % align_base;
+	/* align_base is always a power of 2 */
+	align_diff = icm_mr->icm_start_addr & (align_base - 1);
 	if (align_diff)
 		icm_mr->used_length = align_base - align_diff;
 
-- 
2.23.0


             reply	other threads:[~2019-10-02 12:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-02 12:12 Michal Kubecek [this message]
2019-10-02 14:58 ` [PATCH net] mlx5: avoid 64-bit division in dr_icm_pool_mr_create() Alex Vesker
2019-10-02 15:08   ` David Miller

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=20191002121241.D74DAE04C7@unicorn.suse.cz \
    --to=mkubecek@suse.cz \
    --cc=bp@alien8.de \
    --cc=leon@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=saeedm@mellanox.com \
    --cc=stephen@networkplumber.org \
    --cc=valex@mellanox.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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).