[PATCH V2] cxl: Allow release of contexts which have been OPENED but not STARTED

[PATCH V2] cxl: Allow release of contexts which have been OPENED but not STARTED

[Andrew Donnellan]

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 with a value lower than STARTED, i.e.
OPENED or CLOSED (we can't release a STARTED context as it's currently
using the hardware, and we assume that contexts in any new states which may
be added in future with a value higher than STARTED are also unsafe to
release).

Cc: stable@vger.kernel.org
Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API")
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
---
 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..f49e3e5 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;
 
 	put_device(&ctx->afu->dev);
-- 
Andrew Donnellan              Software Engineer, OzLabs
andrew.donnellan@au1.ibm.com  Australia Development Lab, Canberra
+61 2 6201 8874 (work)        IBM Australia Limited

Re: [PATCH V2] cxl: Allow release of contexts which have been OPENED but not STARTED

[Ian Munsie]

Acked-by: Ian Munsie <imunsie@au1.ibm.com>

Re: [V2] cxl: Allow release of contexts which have been OPENED but not STARTED

[Michael Ellerman]

On Tue, 2015-18-08 at 23:27:18 UTC, 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 with a value lower than STARTED, i.e.
> OPENED or CLOSED (we can't release a STARTED context as it's currently
> using the hardware, and we assume that contexts in any new states which may
> be added in future with a value higher than STARTED are also unsafe to
> release).
> 
> Cc: stable@vger.kernel.org
> Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API")
> Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
> Signed-off-by: Daniel Axtens <dja@axtens.net>
> Acked-by: Ian Munsie <imunsie@au1.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/7c26b9cf5347c2427215

cheers