From: Pavel Machek <pavel@denx.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Stefan Hajnoczi <stefanha@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Stefano Garzarella <sgarzare@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 4.19 07/38] vsock/virtio: stop workers during the .remove()
Date: Tue, 6 Oct 2020 21:34:32 +0200 [thread overview]
Message-ID: <20201006193432.GA8771@duo.ucw.cz> (raw)
In-Reply-To: <20201005142109.015282314@linuxfoundation.org>
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Hi!
> [ Upstream commit 17dd1367389cfe7f150790c83247b68e0c19d106 ]
>
> Before to call vdev->config->reset(vdev) we need to be sure that
> no one is accessing the device, for this reason, we add new variables
> in the struct virtio_vsock to stop the workers during the .remove().
>
> This patch also add few comments before vdev->config->reset(vdev)
> and vdev->config->del_vqs(vdev).
> @@ -621,12 +645,18 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
> INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
> INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
>
> + mutex_lock(&vsock->tx_lock);
> + vsock->tx_run = true;
> + mutex_unlock(&vsock->tx_lock);
> +
> mutex_lock(&vsock->rx_lock);
> virtio_vsock_rx_fill(vsock);
> + vsock->rx_run = true;
> mutex_unlock(&vsock->rx_lock);
>
> mutex_lock(&vsock->event_lock);
> virtio_vsock_event_fill(vsock);
> + vsock->event_run = true;
> mutex_unlock(&vsock->event_lock);
>
This looks like some kind of voodoo code. Locks are just being
allocated few lines above, so there are no other threads accessing
*vsock. That means we don't need to take the locks... right?
At least taking the tx_lock is unneccessary, but probably the others,
too...
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2020-10-06 19:34 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 15:26 [PATCH 4.19 00/38] 4.19.150-rc1 review Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 01/38] mmc: sdhci: Workaround broken command queuing on Intel GLK based IRBIS models Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 02/38] USB: gadget: f_ncm: Fix NDP16 datagram validation Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 03/38] gpio: mockup: fix resource leak in error path Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 04/38] gpio: tc35894: fix up tc35894 interrupt configuration Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 05/38] clk: socfpga: stratix10: fix the divider for the emac_ptp_free_clk Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 06/38] vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 07/38] vsock/virtio: stop workers during the .remove() Greg Kroah-Hartman
2020-10-06 19:34 ` Pavel Machek [this message]
2020-10-07 7:13 ` Stefano Garzarella
2020-10-05 15:26 ` [PATCH 4.19 08/38] vsock/virtio: add transport parameter to the virtio_transport_reset_no_sock() Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 09/38] net: virtio_vsock: Enhance connection semantics Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 10/38] Input: i8042 - add nopnp quirk for Acer Aspire 5 A515 Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 11/38] ftrace: Move RCU is watching check after recursion check Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 12/38] drm/amdgpu: restore proper ref count in amdgpu_display_crtc_set_config Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 13/38] drivers/net/wan/hdlc_fr: Add needed_headroom for PVC devices Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 14/38] drm/sun4i: mixer: Extend regmap max_register Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 15/38] net: dec: de2104x: Increase receive ring size for Tulip Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 16/38] rndis_host: increase sleep time in the query-response loop Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 17/38] nvme-core: get/put ctrl and transport module in nvme_dev_open/release() Greg Kroah-Hartman
2020-10-05 20:58 ` Pavel Machek
2020-10-05 15:26 ` [PATCH 4.19 18/38] drivers/net/wan/lapbether: Make skb->protocol consistent with the header Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 19/38] drivers/net/wan/hdlc: Set skb->protocol before transmitting Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 20/38] mac80211: do not allow bigger VHT MPDUs than the hardware supports Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 21/38] spi: fsl-espi: Only process interrupts for expected events Greg Kroah-Hartman
2020-10-06 19:36 ` Pavel Machek
2020-10-11 19:47 ` Chris Packham
2020-10-11 22:03 ` Pavel Machek
2020-10-05 15:26 ` [PATCH 4.19 22/38] nvme-fc: fail new connections to a deleted host or remote port Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 23/38] gpio: sprd: Clear interrupt when setting the type as edge Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 24/38] pinctrl: mvebu: Fix i2c sda definition for 98DX3236 Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 25/38] nfs: Fix security label length not being reset Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 26/38] clk: samsung: exynos4: mark chipid clock as CLK_IGNORE_UNUSED Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 27/38] iommu/exynos: add missing put_device() call in exynos_iommu_of_xlate() Greg Kroah-Hartman
2020-10-07 9:47 ` Pavel Machek
2020-10-13 8:54 ` Marek Szyprowski
2020-10-13 14:14 ` Pavel Machek
2020-10-05 15:26 ` [PATCH 4.19 28/38] i2c: cpm: Fix i2c_ram structure Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 29/38] Input: trackpoint - enable Synaptics trackpoints Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 30/38] random32: Restore __latent_entropy attribute on net_rand_state Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 31/38] mm: replace memmap_context by meminit_context Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 32/38] mm: dont rely on system state to detect hot-plug operations Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 33/38] net/packet: fix overflow in tpacket_rcv Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 34/38] epoll: do not insert into poll queues until all sanity checks are done Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 35/38] epoll: replace ->visited/visited_list with generation count Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 36/38] epoll: EPOLL_CTL_ADD: close the race in decision to take fast path Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 37/38] ep_create_wakeup_source(): dentry name can change under you Greg Kroah-Hartman
2020-10-05 15:26 ` [PATCH 4.19 38/38] netfilter: ctnetlink: add a range check for l3/l4 protonum Greg Kroah-Hartman
2020-10-05 20:59 ` Pavel Machek
2020-10-05 17:50 ` [PATCH 4.19 00/38] 4.19.150-rc1 review Jon Hunter
2020-10-06 0:23 ` Shuah Khan
2020-10-06 8:52 ` Naresh Kamboju
2020-10-06 18:16 ` Guenter Roeck
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