Re: nbd: add locking to nbd_ioctl

[Pavel Machek <pavel@suse.cz>]

On Fri 2009-01-16 10:24:06, Paul Clements wrote:
> Pavel Machek wrote:
>> The code was written with "oh big kernel lock, please protect me from
>> all the evil" mentality: it does not locks its own data structures, it
>> just hopes that big kernel lock somehow helps.
>>
>> It does not. (My fault).
>>
>> So this uses tx_lock to protect data structures from concurrent use
>> between ioctl and worker threads.
>
> What is the particular problem that this fixes? I thought we had already  
> been careful to take tx_lock where necessary to protect data structures.  
>   Perhaps there is something I missed?

for example lo->sock / lo->file are written to without holding any
lock in current code. (lo->xmit_timeout has similar problem, and other
fields, too).

I used tx_lock to protect those fields.
									Pavel
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