From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v2 1/1] s390: vfio_ap: link the vfio_ap devices to the vfio_ap bus subsystem References: <1550513328-12646-1-git-send-email-pmorel@linux.ibm.com> <1550513328-12646-2-git-send-email-pmorel@linux.ibm.com> <20190219102204.5e050b76.cohuck@redhat.com> From: Christian Borntraeger Date: Tue, 19 Feb 2019 10:44:25 +0100 MIME-Version: 1.0 In-Reply-To: <20190219102204.5e050b76.cohuck@redhat.com> Content-Language: en-US Message-Id: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck , Pierre Morel Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, akrowiak@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com List-ID: On 19.02.2019 10:22, Cornelia Huck wrote: > On Mon, 18 Feb 2019 19:08:48 +0100 > Pierre Morel wrote: > >> Libudev relies on having a subsystem link for non-root devices. To >> avoid libudev (and potentially other userspace tools) choking on the >> matrix device let us introduce a vfio_ap bus and with that the vfio_ap >> bus subsytem, and make the matrix device reside within it. >> >> Doing this we need to suppress the forced link from the matrix device to >> the vfio_ap driver and we suppress the device_type we do not need > > s/suppress/remove/ ? > >> anymore. >> >> Since the associated matrix driver is not the vfio_ap driver any more, >> we have to change the search for the devices on the vfio_ap driver in >> the function vfio_ap_verify_queue_reserved. >> >> Reported-by: Marc Hartmayer >> Reported-by: Christian Borntraeger >> Signed-off-by: Pierre Morel >> --- >> drivers/s390/crypto/vfio_ap_drv.c | 48 +++++++++++++++++++++++++++++------ >> drivers/s390/crypto/vfio_ap_ops.c | 4 +-- >> drivers/s390/crypto/vfio_ap_private.h | 1 + >> 3 files changed, 43 insertions(+), 10 deletions(-) > > (...) > >> @@ -62,6 +58,27 @@ static void vfio_ap_matrix_dev_release(struct device *dev) >> kfree(matrix_dev); >> } >> >> +static int matrix_bus_match(struct device *dev, struct device_driver *drv) >> +{ >> + return 1; >> +} >> + >> +static struct bus_type matrix_bus = { >> + .name = "vfio_ap", >> + .match = &matrix_bus_match, >> +}; >> + >> +static int matrix_probe(struct device *dev) >> +{ >> + return 0; >> +} > > I don't think you need this (the important function is the match > function of the bus). Yes, with diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c index 8e45559795429..8ceec41afe322 100644 --- a/drivers/s390/crypto/vfio_ap_drv.c +++ b/drivers/s390/crypto/vfio_ap_drv.c @@ -68,15 +68,9 @@ static struct bus_type matrix_bus = { .match = &matrix_bus_match, }; -static int matrix_probe(struct device *dev) -{ - return 0; -} - static struct device_driver matrix_driver = { .name = "vfio_ap", .bus = &matrix_bus, - .probe = matrix_probe, }; static int vfio_ap_matrix_dev_create(void) on top things still look fine. > >> + >> +static struct device_driver matrix_driver = { >> + .name = "vfio_ap", >> + .bus = &matrix_bus, >> + .probe = matrix_probe, >> +}; >> + >> static int vfio_ap_matrix_dev_create(void) >> { >> int ret; > > It's a bit annoying that we need to introduce a bus that basically does > nothing, but I think this looks sane. > > Reviewed-by: Cornelia Huck >