From patchwork Sun Aug 9 23:37:52 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rusty Russell X-Patchwork-Id: 40319 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n79NeVcC004305 for ; Sun, 9 Aug 2009 23:40:31 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754098AbZHIXiK (ORCPT ); Sun, 9 Aug 2009 19:38:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754091AbZHIXiJ (ORCPT ); Sun, 9 Aug 2009 19:38:09 -0400 Received: from ozlabs.org ([203.10.76.45]:37103 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753855AbZHIXiE (ORCPT ); Sun, 9 Aug 2009 19:38:04 -0400 Received: from vivaldi.localnet (unknown [150.101.102.135]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPSA id 5EABEDDD0B; Mon, 10 Aug 2009 09:38:04 +1000 (EST) From: Rusty Russell To: "Michael S. Tsirkin" Subject: Re: [PATCHv4 2/2] virtio: refactor find_vqs Date: Mon, 10 Aug 2009 09:07:52 +0930 User-Agent: KMail/1.11.2 (Linux/2.6.28-13-generic; KDE/4.2.2; i686; ; ) Cc: Christian Borntraeger , virtualization@lists.linux-foundation.org, Anthony Liguori , kvm@vger.kernel.org, avi@redhat.com, Carsten Otte , amit.shah@redhat.com References: <200907281244.32124.rusty@rustcorp.com.au> <20090728083308.GA662@redhat.com> In-Reply-To: <20090728083308.GA662@redhat.com> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200908100907.53059.rusty@rustcorp.com.au> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, 28 Jul 2009 06:03:08 pm Michael S. Tsirkin wrote: > On Tue, Jul 28, 2009 at 12:44:31PM +0930, Rusty Russell wrote: > > On Mon, 27 Jul 2009 01:17:09 am Michael S. Tsirkin wrote: > > > This refactors find_vqs, making it more readable and robust, and fixing > > > two regressions from 2.6.30: > > > - double free_irq causing BUG_ON on device removal > > > - probe failure when vq can't be assigned to msi-x vector > > > (reported on old host kernels) > > > > > > An older version of this patch was tested by Amit Shah. > > > > OK, I've applied both of these; I'd like to see a new test by Amit to > > make sure tho. > > > > I really like this cleanup! I looked harder at this code, and my best > > attempts to untangle it further came to very little. This is what I > > ended up with, but it's all cosmetic and can wait until next merge window. > > See what you think. > > > > Thanks! > > Rusty. > > > > virtio_pci: minor MSI-X cleanups > > > > 1) Rename vp_request_vectors to vp_request_msix_vectors, and take > > non-MSI-X case out to caller. > > I'm not sure this change was for the best: we still have a separate code > path under if !use_msix, only in another place now. See below. > And this seems to break the symmetry between request_ and free_vectors. Yes, but unfortunately request_vectors was never really symmetrical :( That's because we didn't do the request_irq's for the per_vector case, because we don't have the names. This is what prevented me from doing a nice encapsulation. > > - err = vp_request_vectors(vdev, nvectors, per_vq_vectors); > > + if (!use_msix) { > > + /* Old style: one normal interrupt for change and all vqs. */ > > + vp_dev->msix_vectors = 0; > > + vp_dev->per_vq_vectors = false; > > + err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, > > + IRQF_SHARED, dev_name(&vdev->dev), vp_dev); > > + if (!err) > > + vp_dev->intx_enabled = 1; > > shorter as vp_dev->intx_enabled = !err > > > + return err; > > Is that all? Don't we need to create the vqs? Oh, yeah :) This patch applies on top. Basically reverts that part, and renames vector to msix_vector, which I think makes the code more readable. virtio: more PCI minor cleanups Signed-off-by: Rusty Russell --- drivers/virtio/virtio_pci.c | 73 +++++++++++++++++++++----------------------- 1 file changed, 36 insertions(+), 37 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -84,7 +84,7 @@ struct virtio_pci_vq_info struct list_head node; /* MSI-X vector (or none) */ - unsigned vector; + unsigned msix_vector; }; /* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */ @@ -349,7 +349,7 @@ error: static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *vq), const char *name, - u16 vector) + u16 msix_vector) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); struct virtio_pci_vq_info *info; @@ -374,7 +374,7 @@ static struct virtqueue *setup_vq(struct info->queue_index = index; info->num = num; - info->vector = vector; + info->msix_vector = msix_vector; size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN)); info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO); @@ -398,10 +398,10 @@ static struct virtqueue *setup_vq(struct vq->priv = info; info->vq = vq; - if (vector != VIRTIO_MSI_NO_VECTOR) { - iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); - vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR); - if (vector == VIRTIO_MSI_NO_VECTOR) { + if (msix_vector != VIRTIO_MSI_NO_VECTOR) { + iowrite16(msix_vector, vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR); + msix_vector = ioread16(vp_dev->ioaddr+VIRTIO_MSI_QUEUE_VECTOR); + if (msix_vector == VIRTIO_MSI_NO_VECTOR) { err = -EBUSY; goto out_assign; } @@ -462,7 +462,8 @@ static void vp_del_vqs(struct virtio_dev list_for_each_entry_safe(vq, n, &vdev->vqs, list) { info = vq->priv; if (vp_dev->per_vq_vectors) - free_irq(vp_dev->msix_entries[info->vector].vector, vq); + free_irq(vp_dev->msix_entries[info->msix_vector].vector, + vq); vp_del_vq(vq); } vp_dev->per_vq_vectors = false; @@ -478,58 +479,56 @@ static int vp_try_to_find_vqs(struct vir bool per_vq_vectors) { struct virtio_pci_device *vp_dev = to_vp_device(vdev); - u16 vector; + u16 msix_vector; int i, err, nvectors, allocated_vectors; if (!use_msix) { /* Old style: one normal interrupt for change and all vqs. */ vp_dev->msix_vectors = 0; - vp_dev->per_vq_vectors = false; err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED, dev_name(&vdev->dev), vp_dev); - if (!err) - vp_dev->intx_enabled = 1; - return err; + if (err) + return err; + } else { + if (per_vq_vectors) { + /* Best option: one for change interrupt, one per vq. */ + nvectors = 1; + for (i = 0; i < nvqs; ++i) + if (callbacks[i]) + ++nvectors; + } else { + /* Second best: one for change, shared for all vqs. */ + nvectors = 2; + } + + err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); + if (err) + goto error_request; } - if (per_vq_vectors) { - /* Best option: one for change interrupt, one per vq. */ - nvectors = 1; - for (i = 0; i < nvqs; ++i) - if (callbacks[i]) - ++nvectors; - } else { - /* Second best: one for change, shared one for all vqs. */ - nvectors = 2; - } - - err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors); - if (err) - goto error_request; - vp_dev->per_vq_vectors = per_vq_vectors; allocated_vectors = vp_dev->msix_used_vectors; for (i = 0; i < nvqs; ++i) { if (!callbacks[i] || !vp_dev->msix_enabled) - vector = VIRTIO_MSI_NO_VECTOR; + msix_vector = VIRTIO_MSI_NO_VECTOR; else if (vp_dev->per_vq_vectors) - vector = allocated_vectors++; + msix_vector = allocated_vectors++; else - vector = VP_MSIX_VQ_VECTOR; - vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], vector); + msix_vector = VP_MSIX_VQ_VECTOR; + vqs[i] = setup_vq(vdev, i, callbacks[i], names[i], msix_vector); if (IS_ERR(vqs[i])) { err = PTR_ERR(vqs[i]); goto error_find; } /* allocate per-vq irq if available and necessary */ - if (vp_dev->per_vq_vectors && vector != VIRTIO_MSI_NO_VECTOR) { - snprintf(vp_dev->msix_names[vector], + if (vp_dev->per_vq_vectors) { + snprintf(vp_dev->msix_names[msix_vector], sizeof *vp_dev->msix_names, "%s-%s", dev_name(&vp_dev->vdev.dev), names[i]); - err = request_irq(vp_dev->msix_entries[vector].vector, - vring_interrupt, 0, - vp_dev->msix_names[vector], vqs[i]); + err = request_irq(msix_vector, vring_interrupt, 0, + vp_dev->msix_names[msix_vector], + vqs[i]); if (err) { vp_del_vq(vqs[i]); goto error_find;