From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F598746F for ; Sun, 17 Sep 2023 20:28:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE803C433C7; Sun, 17 Sep 2023 20:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694982482; bh=5Jy6fN5IVnHwPlXiCUihBan/zpgXEjTbCefhbUvwjQs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c/nsz7fc9lmdDdONXk0bHdAU9thhDPeCb3fD8efmUuF1iLNLDcbC3qRkHPPh41ghn DsdnN065EuqUv7tyB9daMHz9depu1EnSTkxiAqOl4EmPSZppvtQOleYG9+BSuQSXzT jkyEH/Ed2U2IUs6uN60n9iMfZukd0Jvs8wDRjH8Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Gustavo A. R. Silva" , Leon Romanovsky , Sasha Levin Subject: [PATCH 5.15 263/511] RDMA/irdma: Replace one-element array with flexible-array member Date: Sun, 17 Sep 2023 21:11:30 +0200 Message-ID: <20230917191120.189182286@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191113.831992765@linuxfoundation.org> References: <20230917191113.831992765@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva [ Upstream commit 38313c6d2a02c28162e06753b01bd885caf9386d ] One-element and zero-length arrays are deprecated. So, replace one-element array in struct irdma_qvlist_info with flexible-array member. A patch for this was sent a while ago[1]. However, it seems that, at the time, the changes were partially folded[2][3], and the actual flexible-array transformation was omitted. This patch fixes that. The only binary difference seen before/after changes is shown below: | drivers/infiniband/hw/irdma/hw.o | @@ -868,7 +868,7 @@ | drivers/infiniband/hw/irdma/hw.c:484 (discriminator 2) | size += struct_size(iw_qvlist, qv_info, rf->msix_count); | 55b: imul $0x45c,%rdi,%rdi |- 562: add $0x10,%rdi |+ 562: add $0x4,%rdi which is, of course, expected as it reflects the mistake made while folding the patch I've mentioned above. Worth mentioning is the fact that with this change we save 12 bytes of memory, as can be inferred from the diff snapshot above. Notice that: $ pahole -C rdma_qv_info idrivers/infiniband/hw/irdma/hw.o struct irdma_qv_info { u32 v_idx; /* 0 4 */ u16 ceq_idx; /* 4 2 */ u16 aeq_idx; /* 6 2 */ u8 itr_idx; /* 8 1 */ /* size: 12, cachelines: 1, members: 4 */ /* padding: 3 */ /* last cacheline: 12 bytes */ }; Link: https://lore.kernel.org/linux-hardening/20210525230038.GA175516@embeddedor/ [1] Link: https://lore.kernel.org/linux-hardening/bf46b428deef4e9e89b0ea1704b1f0e5@intel.com/ [2] Link: https://lore.kernel.org/linux-rdma/20210520143809.819-1-shiraz.saleem@intel.com/T/#u [3] Fixes: 44d9e52977a1 ("RDMA/irdma: Implement device initialization definitions") Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/ZMpsQrZadBaJGkt4@work Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/hw/irdma/main.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/irdma/main.h b/drivers/infiniband/hw/irdma/main.h index f2e2bc50c6f7b..bd13cc38e5ae1 100644 --- a/drivers/infiniband/hw/irdma/main.h +++ b/drivers/infiniband/hw/irdma/main.h @@ -237,7 +237,7 @@ struct irdma_qv_info { struct irdma_qvlist_info { u32 num_vectors; - struct irdma_qv_info qv_info[1]; + struct irdma_qv_info qv_info[]; }; struct irdma_gen_ops { -- 2.40.1