Re: [RFC] sunrpc: Fix race between work-queue andrpc_killall_tasks.

[Trond Myklebust]

On Wed, 2011-07-06 at 15:49 -0700, greearb@xxxxxxxxxxxxxxx wrote: 
> From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
> 
> The rpc_killall_tasks logic is not locked against
> the work-queue thread, but it still directly modifies
> function pointers and data in the task objects.
> 
> This patch changes the killall-tasks logic to set a flag
> that tells the work-queue thread to terminate the task
> instead of directly calling the terminate logic.
> 
> Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
> ---
> 
> NOTE:  This needs review, as I am still struggling to understand
> the rpc code, and it's quite possible this patch either doesn't
> fully fix the problem or actually causes other issues.  That said,
> my nfs stress test seems to run a bit more stable with this patch applied.

Yes, but I don't see why you are adding a new flag, nor do I see why we
want to keep checking for that flag in the rpc_execute() loop.
rpc_killall_tasks() is not a frequent operation that we want to optimise
for.

How about the following instead?

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