Subject: Re: [PATCH] cxl: Allow release of contexts which have been OPENED but not STARTED

From: Michael Ellerman <[email-masked]>
Date: Tue, 18 Aug 2015 19:19:43 +1000

On Tue, 2015-08-18 at 16:30 +1000, Andrew Donnellan wrote:
> If we open a context but do not start it (either because we do not attempt
> to start it, or because it fails to start for some reason), we are left
> with a context in state OPENED. Previously, cxl_release_context() only
> allowed releasing contexts in state CLOSED, so attempting to release an
> OPENED context would fail.
> 
> In particular, this bug causes available contexts to run out after some EEH
> failures, where drivers attempt to release contexts that have failed to
> start.
> 
> Allow releasing contexts in any state other than STARTED, i.e. OPENED or
> CLOSED (we can't release a STARTED context as it's currently using the
> hardware).
> 
> Cc: [email-masked]
> Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API")
> Signed-off-by: Andrew Donnellan <[email-masked]>
> Signed-off-by: Daniel Axtens <[email-masked]>
> ---
>  drivers/misc/cxl/api.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
> index 6a768a9..1c520b8 100644
> --- a/drivers/misc/cxl/api.c
> +++ b/drivers/misc/cxl/api.c
> @@ -59,7 +59,7 @@ EXPORT_SYMBOL_GPL(cxl_get_phys_dev);
>  
>  int cxl_release_context(struct cxl_context *ctx)
>  {
> -	if (ctx->status != CLOSED)
> +	if (ctx->status == STARTED)
>  		return -EBUSY;

So this doesn't break when you add a new state, is it worth writing it as:

	if (ctx->status >= STARTED)
		return -EBUSY;

?

cheers