From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by dpdk.org (Postfix) with ESMTP id C59AA1150 for ; Wed, 16 Jan 2019 08:48:37 +0100 (CET) X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Jan 2019 23:48:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,485,1539673200"; d="scan'208";a="115040134" Received: from yexl-server.sh.intel.com (HELO localhost) ([10.67.110.206]) by fmsmga007.fm.intel.com with ESMTP; 15 Jan 2019 23:48:35 -0800 Date: Wed, 16 Jan 2019 15:48:36 +0800 From: Ye Xiaolong To: Stephen Hemminger Cc: dev@dpdk.org, Ferruh Yigit Message-ID: <20190116074836.GB39571@intel.com> References: <20190115154626.34516-1-xiaolong.ye@intel.com> <20190116003452.37403-1-xiaolong.ye@intel.com> <20190115173822.25a4a979@shemminger-XPS-13-9360> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190115173822.25a4a979@shemminger-XPS-13-9360> User-Agent: Mutt/1.9.4 (2018-02-28) Subject: Re: [dpdk-dev] [PATCH v2] igb_uio: remove out-of-date comment X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Jan 2019 07:48:38 -0000 Hi, Stephen On 01/15, Stephen Hemminger wrote: >On Wed, 16 Jan 2019 08:34:52 +0800 >Xiaolong Ye wrote: > >> The comment for igbuio_pci_irqhandler is out of date as the code evolves, >> remove it to avoid misleading. >> >> Signed-off-by: Xiaolong Ye >> --- >> kernel/linux/igb_uio/igb_uio.c | 4 ---- >> 1 file changed, 4 deletions(-) >> >> diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c >> index 3cf394bdf..d6ac51e79 100644 >> --- a/kernel/linux/igb_uio/igb_uio.c >> +++ b/kernel/linux/igb_uio/igb_uio.c >> @@ -185,10 +185,6 @@ igbuio_pci_irqcontrol(struct uio_info *info, s32 irq_state) >> return 0; >> } >> >> -/** >> - * This is interrupt handler which will check if the interrupt is for the right device. >> - * If yes, disable it here and will be enable later. >> - */ >> static irqreturn_t >> igbuio_pci_irqhandler(int irq, void *dev_id) >> { > >The comment is partially correct; if you look at the legacy case. > >Maybe better to move the comment to pci_check_and_mask_intx in compat.h? >I see there is another incorrect comment there. > As I tried to understand pci_check_and_mask_intx behavior, I noticed that it was introduced by commit 399a3f0d ("igb_uio: fix IRQ mode handling"), and it was derived from igbuio_set_interrupt_mask, however there were two parameters in igbuio_set_interrupt_mask as below: static int igbuio_set_interrupt_mask(struct rte_uio_pci_dev *udev, int32_t state) while the pci_check_and_mask_intx only has 1 parameter, static bool pci_check_and_mask_intx(struct pci_dev *pdev) but in its function body it still use the "state" accorrding to commit 399a3f0d +static bool pci_check_and_mask_intx(struct pci_dev *pdev) { - /* Some function names changes between 3.2.0 and 3.3.0... */ -#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 3, 0) - pci_unblock_user_cfg_access(pdev); -#else - pci_cfg_access_unlock(pdev); -#endif + bool pending; + uint32_t status; + + pci_block_user_cfg_access(dev); + pci_read_config_dword(pdev, PCI_COMMAND, &status); + + /* interrupt is not ours, goes to out */ + pending = (((status >> 16) & PCI_STATUS_INTERRUPT) != 0); + if (pending) { + uint16_t old, new; + + old = status; + if (state != 0) <=========================== state still in use + new = old & (~PCI_COMMAND_INTX_DISABLE); + else + new = old | PCI_COMMAND_INTX_DISABLE; + + if (old != new) + pci_write_config_word(pdev, PCI_COMMAND, new); + } + pci_unblock_user_cfg_access(dev); + + return pending; and later this was fixed as a typo in commit 5b2f8137 ("igb_uio: fix typos for kernel older than 3.3") which seems not correct. old = status; - if (state != 0) + if (status != 0) I feel like that pci_check_and_mask_intx still needs two parameters from code point of view, please correct me if I was wrong or miss anything, or you think it's sensible, I'll cook a patch for it. Thanks, Xiaolong