From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ea0-f178.google.com (mail-ea0-f178.google.com [209.85.215.178]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id A246A2C00A9 for ; Thu, 3 Oct 2013 18:03:02 +1000 (EST) Received: by mail-ea0-f178.google.com with SMTP id a15so904903eae.9 for ; Thu, 03 Oct 2013 01:02:58 -0700 (PDT) Date: Thu, 3 Oct 2013 11:02:54 +0300 From: Jack Morgenstein To: Alexander Gordeev Subject: Re: [PATCH RFC 46/77] mlx4: Update MSI/MSI-X interrupts enablement code Message-ID: <20131003110254.5f10fbb8@jpm-OptiPlex-GX620> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: linux-mips@linux-mips.org, "VMware, Inc." , linux-nvme@lists.infradead.org, linux-ide@vger.kernel.org, eli@mellanox.com, linux-s390@vger.kernel.org, Andy King , linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Ingo Molnar , linux-pci@vger.kernel.org, iss_storagedev@hp.com, linux-driver@qlogic.com, Tejun Heo , Bjorn Helgaas , Dan Williams , Jon Mason , ogerlitz@mellanox.com, Solarflare linux maintainers , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Ralf Baechle , e1000-devel@lists.sourceforge.net, Martin Schwidefsky , linux390@de.ibm.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2 Oct 2013 12:49:02 +0200 Alexander Gordeev wrote: NACK. This change does not do anything logically as far as I can tell. pci_enable_msix in the current upstream kernel itself calls pci_msix_table_size. The current code yields the same results as the code suggested below. (i.e., the suggested code has no effect on optimality). BTW, pci_msix_table_size never returns a value < 0 (if msix is not enabled, it returns 0 for the table size), so the (err < 0) check here is not correct. (I also do not like using "err" here anyway for the value returned by pci_msix_table_size(). There is no error here, and it is simply confusing. -Jack > As result of recent re-design of the MSI/MSI-X interrupts enabling > pattern this driver has to be updated to use the new technique to > obtain a optimal number of MSI/MSI-X interrupts required. > > Signed-off-by: Alexander Gordeev > --- > drivers/net/ethernet/mellanox/mlx4/main.c | 17 ++++++++--------- > 1 files changed, 8 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c > b/drivers/net/ethernet/mellanox/mlx4/main.c index 60c9f4f..377a5ea > 100644 --- a/drivers/net/ethernet/mellanox/mlx4/main.c > +++ b/drivers/net/ethernet/mellanox/mlx4/main.c > @@ -1852,8 +1852,16 @@ static void mlx4_enable_msi_x(struct mlx4_dev > *dev) int i; > > if (msi_x) { > + err = pci_msix_table_size(dev->pdev); > + if (err < 0) > + goto no_msi; > + > + /* Try if at least 2 vectors are available */ > nreq = min_t(int, dev->caps.num_eqs - > dev->caps.reserved_eqs, nreq); > + nreq = min_t(int, nreq, err); > + if (nreq < 2) > + goto no_msi; > > entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL); > if (!entries) > @@ -1862,17 +1870,8 @@ static void mlx4_enable_msi_x(struct mlx4_dev > *dev) for (i = 0; i < nreq; ++i) > entries[i].entry = i; > > - retry: > err = pci_enable_msix(dev->pdev, entries, nreq); > if (err) { > - /* Try again if at least 2 vectors are > available */ > - if (err > 1) { > - mlx4_info(dev, "Requested %d > vectors, " > - "but only %d MSI-X vectors > available, " > - "trying again\n", nreq, > err); > - nreq = err; > - goto retry; > - } > kfree(entries); > goto no_msi; > }