[{"id":3675060,"web_url":"http://patchwork.ozlabs.org/comment/3675060/","msgid":"","list_archive_url":null,"date":"2026-04-09T03:42:29","subject":"Re: [PATCH 1/2] PCI: endpoint: pci-epf-vntb: Add check to detect\n 'db_count' value of 0","submitter":{"id":68011,"url":"http://patchwork.ozlabs.org/api/people/68011/","name":"Frank Li","email":"Frank.Li@nxp.com"},"content":"On Tue, Apr 07, 2026 at 06:14:20PM +0530, Manivannan Sadhasivam wrote:\n> From: Manivannan Sadhasivam \n>\n> epf_ntb::db_count value should be within 1 to MAX_DB_COUNT. Current code\n> only checks for the upper bound, while the lower bound is unchecked. This\n> can cause a lot of issues in the driver if the user passes 'db_count' as 0.\n>\n> So add a check for 0 also. While at it, remove the redundant 'db_count'\n> assignment.\n>\n> Fixes: e35f56bb0330 (\"PCI: endpoint: Support NTB transfer between RC and EP\")\n> Signed-off-by: Manivannan Sadhasivam \n> ---\n\nReviewed-by: Frank Li \n\n> drivers/pci/endpoint/functions/pci-epf-vntb.c | 9 +++------\n> 1 file changed, 3 insertions(+), 6 deletions(-)\n>\n> diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c\n> index 2256c3062b1a..3d30aa4dbb84 100644\n> --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c\n> +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c\n> @@ -483,7 +483,6 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)\n> {\n> \tconst struct pci_epc_features *epc_features;\n> \tstruct device *dev;\n> -\tu32 db_count;\n> \tint ret;\n>\n> \tdev = &ntb->epf->dev;\n> @@ -495,14 +494,12 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)\n> \t\treturn -EINVAL;\n> \t}\n>\n> -\tdb_count = ntb->db_count;\n> -\tif (db_count > MAX_DB_COUNT) {\n> -\t\tdev_err(dev, \"DB count cannot be more than %d\\n\", MAX_DB_COUNT);\n> +\tif (!ntb->db_count || ntb->db_count > MAX_DB_COUNT) {\n> +\t\tdev_err(dev, \"DB count %d out of range (1 - %d)\\n\",\n> +\t\t\tntb->db_count, MAX_DB_COUNT);\n> \t\treturn -EINVAL;\n> \t}\n>\n> -\tntb->db_count = db_count;\n> -\n> \tif (epc_features->msi_capable) {\n> \t\tret = pci_epc_set_msi(ntb->epf->epc,\n> \t\t\t\t ntb->epf->func_no,\n> --\n> 2.51.0\n>","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=nxp.com header.i=@nxp.com header.a=rsa-sha256\n header.s=selector1 header.b=h7NyO0S4;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; 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dkim=pass\n header.d=nxp.com; arc=none"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector1;\n h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;\n bh=m6EwSW+j87gVLmyo/1WGmBEXDxw6e3us+9LCSR2pdHs=;\n b=h7NyO0S4iP3qztdvgRwvlTJ2lk64dXi7DRvD21aG8yp55zBDsEOPnVJnSb1lJJYOTDsIGrzLTJAymz2rWVEiRU9c0dtGC6eXuFOAHJy0jzikoEYotjrXJ1gzhLMIqZZy0rtWG1zTsUHRdhfUSMTYJwl7HKSn2w429aZitLuSBgUCGh50m5t72jcApGML37G/3VKsQPJPrEhY1TMyZOhmQZjkqtGuy/OfRhu6UiKMjUBpzPjCugSh1GlGhEC0V8cA+ZkTA84CghB4ji7CsmK99/LEhsA3TEy0gPDxKFwB4SEfBA9KtQzWtyMFZoGnsIhw64HZLDAzWZNtP6GAnx7qnw==","Date":"Wed, 8 Apr 2026 23:42:29 -0400","From":"Frank Li ","To":"Manivannan Sadhasivam ","Cc":"mani@kernel.org, kwilczynski@kernel.org, kishon@kernel.org,\n\tbhelgaas@google.com, jdmason@kudzu.us, dave.jiang@intel.com,\n\tallenbh@gmail.com, ntb@lists.linux.dev, linux-pci@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org, den@valinux.co.jp","Subject":"Re: [PATCH 1/2] PCI: endpoint: pci-epf-vntb: Add check to detect\n 'db_count' value of 0","Message-ID":"","References":"<20260407124421.282766-1-mani@kernel.org>\n <20260407124421.282766-2-mani@kernel.org>","Content-Type":"text/plain; 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