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X-CSE-ConnectionGUID: Cc7z6lNzQcKuufABsFS+Nw== X-CSE-MsgGUID: 6Uj3MTXNRf6n2iGl8Fhf8Q== X-IronPort-AV: E=McAfee;i="6800,10657,11712"; a="98552756" X-IronPort-AV: E=Sophos;i="6.21,310,1763452800"; d="scan'208";a="98552756" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2026 08:47:44 -0800 X-CSE-ConnectionGUID: D4OKonMzS0OuYauDIlGuAA== X-CSE-MsgGUID: B1ez37z+RhK0joDrepZ6SQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,310,1763452800"; d="scan'208";a="215506610" Received: from gabaabhi-mobl2.amr.corp.intel.com (HELO [10.125.111.98]) ([10.125.111.98]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2026 08:47:43 -0800 Message-ID: <8ff7a843-bc0d-4ee0-b1d4-94d31e071fcd@intel.com> Date: Wed, 25 Feb 2026 09:47:43 -0700 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/10] NTB: epf: Make db_valid_mask cover only real doorbell bits To: Koichiro Den , Frank.Li@nxp.com, kishon@kernel.org, jdmason@kudzu.us, mani@kernel.org, allenbh@gmail.com, kwilczynski@kernel.org, bhelgaas@google.com, jbrunet@baylibre.com, lpieralisi@kernel.org Cc: linux-pci@vger.kernel.org, ntb@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260224133459.1741537-1-den@valinux.co.jp> <20260224133459.1741537-8-den@valinux.co.jp> Content-Language: en-US From: Dave Jiang In-Reply-To: <20260224133459.1741537-8-den@valinux.co.jp> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/24/26 6:34 AM, Koichiro Den wrote: > ndev->db_count includes an unused doorbell slot due to the legacy extra > offset in the peer doorbell path. db_valid_mask must cover only the real > doorbell bits and exclude the unused slot. > > Set db_valid_mask to BIT_ULL(db_count - 1) - 1. > > Fixes: 812ce2f8d14e ("NTB: Add support for EPF PCI Non-Transparent Bridge") > Signed-off-by: Koichiro Den > --- > drivers/ntb/hw/epf/ntb_hw_epf.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c > index bce7130fec39..ee499eaed4f3 100644 > --- a/drivers/ntb/hw/epf/ntb_hw_epf.c > +++ b/drivers/ntb/hw/epf/ntb_hw_epf.c > @@ -580,7 +580,13 @@ static int ntb_epf_init_dev(struct ntb_epf_dev *ndev) > return ret; > } > > - ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1; > + if (ndev->db_count < NTB_EPF_MIN_DB_COUNT) { > + dev_err(dev, "db_count %u is less than %u\n", ndev->db_count, > + NTB_EPF_MIN_DB_COUNT); > + return -EINVAL; > + } > + > + ndev->db_valid_mask = BIT_ULL(ndev->db_count - 1) - 1; I would suggest adding a comment in the code for why this is for future readers. DJ > ndev->mw_count = readl(ndev->ctrl_reg + NTB_EPF_MW_COUNT); > ndev->spad_count = readl(ndev->ctrl_reg + NTB_EPF_SPAD_COUNT); >