From: Alex Williamson <alex.williamson@redhat.com>
To: Antonios Motakis <a.motakis@virtualopensystems.com>
Cc: kvmarm@lists.cs.columbia.edu, iommu@lists.linux-foundation.org,
tech@virtualopensystems.com, a.rigo@virtualopensystems.com,
kvm@vger.kernel.org, christoffer.dall@linaro.org,
will.deacon@arm.com, kim.phillips@freescale.com,
stuart.yoder@freescale.com, eric.auger@linaro.org,
Alexander Gordeev <agordeev@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v6 17/20] vfio: add local lock in virqfd instead of depending on VFIO PCI
Date: Thu, 05 Jun 2014 16:19:10 -0600 [thread overview]
Message-ID: <1402006750.9207.267.camel@ul30vt.home> (raw)
In-Reply-To: <1401987808-23596-18-git-send-email-a.motakis@virtualopensystems.com>
On Thu, 2014-06-05 at 19:03 +0200, Antonios Motakis wrote:
> Sharing the same spinlock with the VFIO bus driver is not necessary for
> the virqfd code, so remove that dependency.
I like the idea of consolidating this code, but I need more
justification for why the use of the lock here is independent of the bus
driver and why it's ok to move from a per-device lock to a global lock.
Thanks,
Alex
>
> Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
> ---
> drivers/vfio/pci/vfio_pci_intrs.c | 10 +++++-----
> drivers/vfio/virqfd.c | 24 +++++++++++++-----------
> include/linux/vfio.h | 3 +--
> 3 files changed, 19 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index 3f909bb..e56c814 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -226,8 +226,8 @@ static int vfio_intx_set_signal(struct vfio_pci_device *vdev, int fd)
> static void vfio_intx_disable(struct vfio_pci_device *vdev)
> {
> vfio_intx_set_signal(vdev, -1);
> - virqfd_disable(vdev, &vdev->ctx[0].unmask);
> - virqfd_disable(vdev, &vdev->ctx[0].mask);
> + virqfd_disable(&vdev->ctx[0].unmask);
> + virqfd_disable(&vdev->ctx[0].mask);
> vdev->irq_type = VFIO_PCI_NUM_IRQS;
> vdev->num_ctx = 0;
> kfree(vdev->ctx);
> @@ -377,8 +377,8 @@ static void vfio_msi_disable(struct vfio_pci_device *vdev, bool msix)
> vfio_msi_set_block(vdev, 0, vdev->num_ctx, NULL, msix);
>
> for (i = 0; i < vdev->num_ctx; i++) {
> - virqfd_disable(vdev, &vdev->ctx[i].unmask);
> - virqfd_disable(vdev, &vdev->ctx[i].mask);
> + virqfd_disable(&vdev->ctx[i].unmask);
> + virqfd_disable(&vdev->ctx[i].mask);
> }
>
> if (msix) {
> @@ -415,7 +415,7 @@ static int vfio_pci_set_intx_unmask(struct vfio_pci_device *vdev,
> vfio_send_intx_eventfd, NULL,
> &vdev->ctx[0].unmask, fd);
>
> - virqfd_disable(vdev, &vdev->ctx[0].unmask);
> + virqfd_disable(&vdev->ctx[0].unmask);
> }
>
> return 0;
> diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
> index 9cf2842..4528450 100644
> --- a/drivers/vfio/virqfd.c
> +++ b/drivers/vfio/virqfd.c
> @@ -17,6 +17,7 @@
> #include "pci/vfio_pci_private.h"
>
> static struct workqueue_struct *vfio_irqfd_cleanup_wq;
> +static spinlock_t lock;
>
> int __init vfio_pci_virqfd_init(void)
> {
> @@ -25,6 +26,8 @@ int __init vfio_pci_virqfd_init(void)
> if (!vfio_irqfd_cleanup_wq)
> return -ENOMEM;
>
> + spin_lock_init(&lock);
> +
> return 0;
> }
>
> @@ -53,21 +56,21 @@ static int virqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
>
> if (flags & POLLHUP) {
> unsigned long flags;
> - spin_lock_irqsave(&virqfd->vdev->irqlock, flags);
> + spin_lock_irqsave(&lock, flags);
>
> /*
> * The eventfd is closing, if the virqfd has not yet been
> * queued for release, as determined by testing whether the
> - * vdev pointer to it is still valid, queue it now. As
> + * virqfd pointer to it is still valid, queue it now. As
> * with kvm irqfds, we know we won't race against the virqfd
> - * going away because we hold wqh->lock to get here.
> + * going away because we hold the lock to get here.
> */
> if (*(virqfd->pvirqfd) == virqfd) {
> *(virqfd->pvirqfd) = NULL;
> virqfd_deactivate(virqfd);
> }
>
> - spin_unlock_irqrestore(&virqfd->vdev->irqlock, flags);
> + spin_unlock_irqrestore(&lock, flags);
> }
>
> return 0;
> @@ -143,16 +146,16 @@ int virqfd_enable(struct vfio_pci_device *vdev,
> * we update the pointer to the virqfd under lock to avoid
> * pushing multiple jobs to release the same virqfd.
> */
> - spin_lock_irq(&vdev->irqlock);
> + spin_lock_irq(&lock);
>
> if (*pvirqfd) {
> - spin_unlock_irq(&vdev->irqlock);
> + spin_unlock_irq(&lock);
> ret = -EBUSY;
> goto err_busy;
> }
> *pvirqfd = virqfd;
>
> - spin_unlock_irq(&vdev->irqlock);
> + spin_unlock_irq(&lock);
>
> /*
> * Install our own custom wake-up handling so we are notified via
> @@ -189,19 +192,18 @@ err_fd:
> return ret;
> }
>
> -void virqfd_disable(struct vfio_pci_device *vdev,
> - struct virqfd **pvirqfd)
> +void virqfd_disable(struct virqfd **pvirqfd)
> {
> unsigned long flags;
>
> - spin_lock_irqsave(&vdev->irqlock, flags);
> + spin_lock_irqsave(&lock, flags);
>
> if (*pvirqfd) {
> virqfd_deactivate(*pvirqfd);
> *pvirqfd = NULL;
> }
>
> - spin_unlock_irqrestore(&vdev->irqlock, flags);
> + spin_unlock_irqrestore(&lock, flags);
>
> /*
> * Block until we know all outstanding shutdown jobs have completed.
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 43968e8..44c9808 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -123,7 +123,6 @@ extern int virqfd_enable(struct vfio_pci_device *vdev,
> int (*handler)(struct vfio_pci_device *, void *),
> void (*thread)(struct vfio_pci_device *, void *),
> void *data, struct virqfd **pvirqfd, int fd);
> -extern void virqfd_disable(struct vfio_pci_device *vdev,
> - struct virqfd **pvirqfd);
> +extern void virqfd_disable(struct virqfd **pvirqfd);
>
> #endif /* VFIO_H */
next prev parent reply other threads:[~2014-06-05 22:19 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1401987808-23596-1-git-send-email-a.motakis@virtualopensystems.com>
2014-06-05 17:03 ` [RFC PATCH v6 01/20] iommu/arm-smmu: change IOMMU_EXEC to IOMMU_NOEXEC Antonios Motakis
2014-06-16 15:04 ` Will Deacon
2014-06-05 17:03 ` [RFC PATCH v6 02/20] iommu: add capability IOMMU_CAP_NOEXEC Antonios Motakis
2014-06-05 20:03 ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 03/20] iommu/arm-smmu: add IOMMU_CAP_NOEXEC to the ARM SMMU driver Antonios Motakis
2014-06-16 15:04 ` Will Deacon
2014-06-16 15:25 ` Alex Williamson
2014-06-16 15:30 ` Will Deacon
2014-06-05 17:03 ` [RFC PATCH v6 04/20] iommu/arm-smmu: add capability IOMMU_CAP_INTR_REMAP Antonios Motakis
2014-06-05 18:31 ` Varun Sethi
2014-06-08 10:31 ` Christoffer Dall
2014-06-16 14:53 ` Joerg Roedel
2014-06-16 15:13 ` Will Deacon
2014-06-16 15:21 ` Joerg Roedel
2014-06-16 15:25 ` Will Deacon
2014-06-16 15:38 ` Joerg Roedel
2014-06-26 18:08 ` Chalamarla, Tirumalesh
2014-06-26 18:15 ` Chalamarla, Tirumalesh
2014-06-26 18:41 ` Chalamarla, Tirumalesh
2014-06-26 19:00 ` Alex Williamson
2014-06-26 19:10 ` Chalamarla, Tirumalesh
2014-06-26 19:36 ` Alex Williamson
2014-06-27 8:47 ` Will Deacon
2014-06-27 21:57 ` Chalamarla, Tirumalesh
2014-06-28 7:05 ` Marc Zyngier
2014-06-16 15:30 ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 05/20] vfio/iommu_type1: support for platform bus devices on ARM Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 06/20] vfio: introduce the VFIO_DMA_MAP_FLAG_NOEXEC flag Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 07/20] vfio/iommu_type1: implement " Antonios Motakis
2014-06-05 20:48 ` Alex Williamson
2014-06-05 17:03 ` [RFC PATCH v6 08/20] driver core: platform: add device binding path 'driver_override' Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 09/20] vfio/platform: initial skeleton of VFIO support for platform devices Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 10/20] vfio/platform: return info for device and its memory mapped IO regions Antonios Motakis
2014-06-05 21:14 ` Alex Williamson
2014-06-06 16:39 ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 11/20] vfio/platform: read and write support for the device fd Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 12/20] vfio/platform: support MMAP of MMIO regions Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 13/20] vfio/platform: return IRQ info Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 14/20] vfio/platform: initial interrupts support Antonios Motakis
2014-06-08 10:09 ` Christoffer Dall
2014-09-02 16:07 ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 15/20] vfio/platform: support for maskable and automasked interrupts Antonios Motakis
2014-06-08 10:17 ` Christoffer Dall
2014-09-02 16:06 ` Antonios Motakis
2014-09-10 10:13 ` Christoffer Dall
2014-09-11 17:20 ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 16/20] vfio: move eventfd support code for VFIO_PCI to a sepparate file Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 17/20] vfio: add local lock in virqfd instead of depending on VFIO PCI Antonios Motakis
2014-06-05 22:19 ` Alex Williamson [this message]
2014-06-06 16:57 ` Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 18/20] vfio: pass an opaque pointer on virqfd initialization Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 19/20] vfio: initialize the virqfd workqueue in VFIO generic code Antonios Motakis
2014-06-05 17:03 ` [RFC PATCH v6 20/20] vfio/platform: implement IRQ masking/unmasking via an eventfd Antonios Motakis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1402006750.9207.267.camel@ul30vt.home \
--to=alex.williamson@redhat.com \
--cc=a.motakis@virtualopensystems.com \
--cc=a.rigo@virtualopensystems.com \
--cc=agordeev@redhat.com \
--cc=bhelgaas@google.com \
--cc=christoffer.dall@linaro.org \
--cc=eric.auger@linaro.org \
--cc=iommu@lists.linux-foundation.org \
--cc=kim.phillips@freescale.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-kernel@vger.kernel.org \
--cc=stuart.yoder@freescale.com \
--cc=tech@virtualopensystems.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).