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Message-ID: <4971046c-213b-494b-bf4b-ebe3feaa03c1@vivo.com>
Date: Thu, 16 May 2024 10:12:25 +0800
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 3/5] dm: support retrieving struct dm_target from struct
 dm_dev
Content-Language: en-US
To: Benjamin Marzinski <bmarzins@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@kernel.org>,
 Mikulas Patocka <mpatocka@redhat.com>, dm-devel@lists.linux.dev,
 linux-kernel@vger.kernel.org
References: <20240514090445.2847-1-yang.yang@vivo.com>
 <20240514090445.2847-4-yang.yang@vivo.com> <ZkTXzG1yrPmW64Z6@redhat.com>
 <ZkTcHCM49DDqhaYD@redhat.com>
From: YangYang <yang.yang@vivo.com>
In-Reply-To: <ZkTcHCM49DDqhaYD@redhat.com>
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On 2024/5/16 0:00, Benjamin Marzinski wrote:
> On Wed, May 15, 2024 at 11:42:04AM -0400, Benjamin Marzinski wrote:
>> When a target calls dm_get_device(), if it adds a new table device to
>> t->devices, then it's the first target in this table to use that device.
>> If flush_pass_around is set for this target, then it also sets
>> sends_pass_around_flush. In __send_empty_flush() if the table has
>> flush_pass_around set, when you iterate through the devices, you only
> 
> Err, "When you iterate through the *targets*, you only ..." In this
> method you don't iterate through the list of devices (which is supposed
> to be protected by t->devices_lock).

I'm not very familiar with this area, I thought that the device list
of an active table cannot be modified, so it doesn't need to be
protected by t->devices_lock.

> 
>> call __send_empty_flush_bios() for the ones with sends_pass_around_flush
>> set.
>>
>> Or am I overlooking something?
>>
>> -Ben
>