Hi Sagi
Thanks for your kindly response.
And sorry for my bad description.
On 02/11/2018 07:17 PM, Sagi Grimberg wrote:
>> namespaces_mutext is used to synchronize the operations on ctrl
>> namespaces list. Most of the time, it is a read operation. It is
>> better to change it from mutex to rwsem.
>>
>> On the other hand, the namespaces mutex could introduce circular
>> dependency easily.
>
> On the other hand of what?
>
> Also, can you give an example of such?
>
We have a lot of interface in nvme core that need to hold this
namespace_mutex and looks like we will have more.
The mutex will trouble us in following scenario.
For example:
context A context B
nvme_xxx_xxx nvme_xxx_xxx
-> hold namespace_mutex -> try to require namespace_mutex
-> sync context B
Keith's patch will incur this.
http://lists.infradead.org/pipermail/linux-nvme/2018-February/015605.html
Because I add a interface that will hold namespace_mutex, so I add this
patchset here.
Thanks
Jianchao
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