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From: | Tony Krowiak |
Subject: | Re: [qemu-s390x] [RFC 05/19] s390/zcrypt: base implementation of AP matrix device driver |
Date: | Tue, 14 Nov 2017 13:15:27 -0500 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 |
On 11/14/2017 12:00 PM, Cornelia Huck wrote:
On Tue, 14 Nov 2017 11:37:05 -0500 Tony Krowiak <address@hidden> wrote:On 11/14/2017 07:40 AM, Cornelia Huck wrote:On Fri, 13 Oct 2017 13:38:50 -0400 Tony Krowiak <address@hidden> wrote:diff --git a/drivers/s390/crypto/ap_matrix_bus.c b/drivers/s390/crypto/ap_matrix_bus.c index 4eb1e3c..66bfa54 100644 --- a/drivers/s390/crypto/ap_matrix_bus.c +++ b/drivers/s390/crypto/ap_matrix_bus.c @@ -75,10 +75,18 @@ static int ap_matrix_dev_create(void) return 0; }+struct ap_matrix *ap_matrix_get_device(void)+{ + return matrix;See the comments I had for the previous patch. In particular, I think it is better to retrieve a pointer to the matrix device via driver core methods.I got some objections to creating a new bus and since there will only ever be a single AP matrix device, I decided there really wasn't a need for an AP matrix bus and got rid of it. I opted instead to create the matrix device in the init function of the vfio_ap_matrix driver. Rather than passing around a pointer, I put the following in vfio_ap_matrix_private.h: struct ap_matrix { struct device device; spinlock_t qlock; struct list_head queues; }; extern struct ap_matrix ap_matrix; ... and declared the ap_matrix in the driver (vfio_ap_matrix_drv.c) file as: struct ap_matrix ap_matrix; Does this seem like a reasonable approach?Getting rid of the bus as overhead is not unreasonable. I'm feeling a bit queasy about the extern, however. I'd prefer a getter function (that also makes sure refcounting rules are followed).
I now think I can avoid having to reference the ap_matrix device from multiple places. The reason the device is referenced in vfio_ap_matrix_ops.cis because there is a need for information about the AP queues that have been bound to the vfio_ap_matrix device driver. If interfaces are provided by the
vfio_ap_matrix device driver to access the needed information, it won't be necessary to reference the ap_matrix device directly in vfio_ap_matrix_ops. I think this would be a better solution, don't you?
The only way would be to roll up vfio_ap_matrix_ops.c into vfio_ap_matrix_drv.c. I followed the pattern establishedWe can't get around referencing this device from multiple files, can we?
by the vfio_ccw
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