DPDK patches and discussions
 help / color / mirror / Atom feed
From: Jeff Guo <jia.guo@intel.com>
To: Matan Azrad <matan@mellanox.com>,
	"konstantin.ananyev@intel.com" <konstantin.ananyev@intel.com>,
	"anatoly.burakov@intel.com" <anatoly.burakov@intel.com>,
	Thomas Monjalon <thomas@monjalon.net>,
	"bernard.iremonger@intel.com" <bernard.iremonger@intel.com>,
	"jingjing.wu@intel.com" <jingjing.wu@intel.com>,
	"wenzhuo.lu@intel.com" <wenzhuo.lu@intel.com>
Cc: "ferruh.yigit@intel.com" <ferruh.yigit@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"helin.zhang@intel.com" <helin.zhang@intel.com>,
	"shaopeng.he@intel.com" <shaopeng.he@intel.com>
Subject: Re: [dpdk-dev] [PATCH 2/3] vfio: fix to add handler lock for hot-unplug
Date: Wed, 7 Nov 2018 14:15:05 +0800
Message-ID: <f9bcc4a6-c23c-14a0-2e54-384747dd059b@intel.com> (raw)
In-Reply-To: <AM0PR0502MB4019017DE68905703BEEB0F1D2CB0@AM0PR0502MB4019.eurprd05.prod.outlook.com>


On 11/6/2018 2:23 PM, Matan Azrad wrote:
> Hi Jeff
>
> Can you detail more in the commit log that we can understand the synchronization problematic scenario. And how does this commit fix it?
>

Please check my reply in the 1/3 mail. And explain more here is that, 
when device be hot-unplugged in vfio, the req notifier will invoked, 
then user space could release device resource in user space side,

then vfio check that the device be released out from the device group, 
it will take the device control again and trigger the device kernel 
release processing, at the mean time it will sent remove uevent to

user space. Here although the req handler seems will always process 
before uevent handler, but even for fast path and slow path protection 
of device accessing when device is removing , it should also be need.

what do you think about that?


>> -----Original Message-----
>> From: Jeff Guo <jia.guo@intel.com>
>> Sent: Tuesday, November 6, 2018 8:07 AM
>> To: konstantin.ananyev@intel.com; anatoly.burakov@intel.com; Thomas
>> Monjalon <thomas@monjalon.net>; bernard.iremonger@intel.com;
>> jingjing.wu@intel.com; wenzhuo.lu@intel.com
>> Cc: ferruh.yigit@intel.com; dev@dpdk.org; jia.guo@intel.com;
>> helin.zhang@intel.com; Matan Azrad <matan@mellanox.com>;
>> shaopeng.he@intel.com
>> Subject: [PATCH 2/3] vfio: fix to add handler lock for hot-unplug
>>
>> This patch add hot-unplug handler lock and unlock in device request handler
>> when process bus and device resource, in order to avoid the synchronization
>> issue when device be hot-unplugged.
>>
>> Fixes: c115fd000c32 ("vfio: handle hotplug request notifier")
>> Signed-off-by: Jeff Guo <jia.guo@intel.com>
>> ---
>>   drivers/bus/pci/linux/pci_vfio.c | 14 +++++++++++++-
>>   1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
>> index 305cc06..d2c8410 100644
>> --- a/drivers/bus/pci/linux/pci_vfio.c
>> +++ b/drivers/bus/pci/linux/pci_vfio.c
>> @@ -19,6 +19,7 @@
>>   #include <rte_vfio.h>
>>   #include <rte_eal.h>
>>   #include <rte_bus.h>
>> +#include <rte_spinlock.h>
>>
>>   #include "eal_filesystem.h"
>>
>> @@ -35,6 +36,14 @@
>>    * This file is only compiled if CONFIG_RTE_EAL_VFIO is set to "y".
>>    */
>>
>> +/*
>> + * spinlock for device hot-unplug failure handling. If it try to access
>> +bus or
>> + * device, such as handle sigbus on bus or handle memory failure for
>> +device
>> + * just need to use this lock. It could protect the bus and the device
>> +to avoid
>> + * race condition.
>> + */
>> +static rte_spinlock_t failure_handle_lock = RTE_SPINLOCK_INITIALIZER;
>> +
>>   #ifdef VFIO_PRESENT
>>
>>   #ifndef PAGE_SIZE
>> @@ -289,11 +298,12 @@ pci_vfio_req_handler(void *param)
>>   	int ret;
>>   	struct rte_device *device = (struct rte_device *)param;
>>
>> +	rte_spinlock_lock(&failure_handle_lock);
>>   	bus = rte_bus_find_by_device(device);
>>   	if (bus == NULL) {
>>   		RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
>>   			device->name);
>> -		return;
>> +		goto handle_end;
>>   	}
>>
>>   	/*
>> @@ -306,6 +316,8 @@ pci_vfio_req_handler(void *param)
>>   		RTE_LOG(ERR, EAL,
>>   			"Can not handle hot-unplug for device (%s)\n",
>>   			device->name);
>> +handle_end:
>> +	rte_spinlock_unlock(&failure_handle_lock);
>>   }
>>
>>   /* enable notifier (only enable req now) */
>> --
>> 2.7.4

  reply	other threads:[~2018-11-07  6:15 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-06  6:07 [dpdk-dev] [PATCH 0/3] fix vfio hot-unplug issue Jeff Guo
2018-11-06  6:07 ` [dpdk-dev] [PATCH 1/3] eal: fix lock issue for hot-unplug Jeff Guo
2018-11-06  6:22   ` Matan Azrad
2018-11-07  5:49     ` Jeff Guo
2018-11-08  7:08       ` Matan Azrad
2018-11-06  6:07 ` [dpdk-dev] [PATCH 2/3] vfio: fix to add handler lock " Jeff Guo
2018-11-06  6:23   ` Matan Azrad
2018-11-07  6:15     ` Jeff Guo [this message]
2018-11-08  7:20       ` Matan Azrad
2018-11-08  8:30         ` Jeff Guo
2018-11-06  6:07 ` [dpdk-dev] [PATCH 3/3] app/testpmd: fix callback issue " Jeff Guo
2018-11-06  6:36   ` Matan Azrad
2018-11-07  7:30     ` Jeff Guo
2018-11-07 11:05       ` Ananyev, Konstantin
2018-11-08  7:28         ` Matan Azrad
2018-11-08  8:49           ` Jeff Guo
2018-11-08  9:35             ` Matan Azrad
2018-11-09  3:55               ` Jeff Guo
2018-11-09  5:24                 ` Matan Azrad
2018-11-09  6:17                   ` Jeff Guo
     [not found]                     ` <AM0PR0502MB401938411A7E2BA9E76576A2D2C00@AM0PR0502MB4019.eurprd05.prod.outlook.com>
2018-11-12  1:35                       ` Thomas Monjalon
2018-11-14  9:32                         ` Jeff Guo
2018-11-15  9:18 ` [dpdk-dev] [PATCH V2 0/3] fix vfio hot-unplug issue Jeff Guo
2018-11-15  9:18   ` Jeff Guo
2018-11-18 16:19     ` Thomas Monjalon
2018-11-15  9:18   ` [dpdk-dev] [PATCH V2 1/3] eal: fix lock issue for hot-unplug Jeff Guo
2018-11-15  9:18   ` [dpdk-dev] [PATCH V2 2/3] vfio: fix to add handler lock " Jeff Guo
2018-11-15  9:18   ` [dpdk-dev] [PATCH V2 3/3] app/testpmd: fix callback issue " Jeff Guo

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=f9bcc4a6-c23c-14a0-2e54-384747dd059b@intel.com \
    --to=jia.guo@intel.com \
    --cc=anatoly.burakov@intel.com \
    --cc=bernard.iremonger@intel.com \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@intel.com \
    --cc=helin.zhang@intel.com \
    --cc=jingjing.wu@intel.com \
    --cc=konstantin.ananyev@intel.com \
    --cc=matan@mellanox.com \
    --cc=shaopeng.he@intel.com \
    --cc=thomas@monjalon.net \
    --cc=wenzhuo.lu@intel.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

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git