2022-08-26 05:11:25

by Mika Penttilä

Subject: [PATCH v8] mm/hmm/test: use char dev with struct device to get device node

From: Mika Penttilä <[email protected]>

HMM selftests use an in-kernel pseudo device to emulate device
memory. The pseudo device registers a major device range for two or
four pseudo device instances. User space has a script that
reads /proc/devices in order to find the assigned major number,
and sends that to mknod(1), once for each node.

Change this to properly use cdev and struct device APIs.

Delete the /proc/devices parsing from the user-space test script, now
that it is unnecessary.

Also, deleted an unused field in struct dmirror_device: devmem.

Signed-off-by: Mika Penttilä <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Vlastimil Babka <[email protected]>
---
v8:
- refresh for device coherent
v7:
- collected more Review-by's
v6:
- remove device names array
- check return value of dev_set_name()
v5:
- fix whitespace
. delete unused structure field
v4:
- fix commit log
v3:
- use cdev_device_add() instead of miscdevice
v2:
- Cleanups per review comments from John Hubbard
- Added Tested-by and Ccs

lib/test_hmm.c | 13 ++++++++++---
tools/testing/selftests/vm/test_hmm.sh | 10 ----------
2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index e3965cafd27c..6a33f6b1b465 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -107,8 +107,8 @@ struct dmirror_chunk {
*/
struct dmirror_device {
struct cdev cdevice;
- struct hmm_devmem *devmem;
unsigned int zone_device_type;
+ struct device device;

unsigned int devmem_capacity;
unsigned int devmem_count;
@@ -1390,7 +1390,14 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id)

cdev_init(&mdevice->cdevice, &dmirror_fops);
mdevice->cdevice.owner = THIS_MODULE;
- ret = cdev_add(&mdevice->cdevice, dev, 1);
+ device_initialize(&mdevice->device);
+ mdevice->device.devt = dev;
+
+ ret = dev_set_name(&mdevice->device, "hmm_dmirror%u", id);
+ if (ret)
+ return ret;
+
+ ret = cdev_device_add(&mdevice->cdevice, &mdevice->device);
if (ret)
return ret;

@@ -1416,7 +1423,7 @@ static void dmirror_device_remove(struct dmirror_device *mdevice)
kfree(mdevice->devmem_chunks);
}

- cdev_del(&mdevice->cdevice);
+ cdev_device_del(&mdevice->cdevice, &mdevice->device);
}

static int __init hmm_dmirror_init(void)
diff --git a/tools/testing/selftests/vm/test_hmm.sh b/tools/testing/selftests/vm/test_hmm.sh
index 539c9371e592..46e19b5d648d 100755
--- a/tools/testing/selftests/vm/test_hmm.sh
+++ b/tools/testing/selftests/vm/test_hmm.sh
@@ -52,21 +52,11 @@ load_driver()
usage
fi
fi
- if [ $? == 0 ]; then
- major=$(awk "\$2==\"HMM_DMIRROR\" {print \$1}" /proc/devices)
- mknod /dev/hmm_dmirror0 c $major 0
- mknod /dev/hmm_dmirror1 c $major 1
- if [ $# -eq 2 ]; then
- mknod /dev/hmm_dmirror2 c $major 2
- mknod /dev/hmm_dmirror3 c $major 3
- fi
- fi
}

unload_driver()
{
modprobe -r $DRIVER > /dev/null 2>&1
- rm -f /dev/hmm_dmirror?
}

run_smoke()
--
2.17.1

2022-09-06 23:32:28

by Jason Gunthorpe

Subject: Re: [PATCH v8] mm/hmm/test: use char dev with struct device to get device node

On Fri, Aug 26, 2022 at 08:06:31AM +0300, [email protected] wrote:
> From: Mika Penttilä <[email protected]>
>
> HMM selftests use an in-kernel pseudo device to emulate device
> memory. The pseudo device registers a major device range for two or
> four pseudo device instances. User space has a script that
> reads /proc/devices in order to find the assigned major number,
> and sends that to mknod(1), once for each node.
>
> Change this to properly use cdev and struct device APIs.
>
> Delete the /proc/devices parsing from the user-space test script, now
> that it is unnecessary.
>
> Also, deleted an unused field in struct dmirror_device: devmem.
>
> Signed-off-by: Mika Penttilä <[email protected]>
> Reviewed-by: John Hubbard <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> Reviewed-by: Jason Gunthorpe <[email protected]>
> Cc: Alistair Popple <[email protected]>
> Cc: Ralph Campbell <[email protected]>
> Cc: Vlastimil Babka <[email protected]>

Andrew, this looks OK, can you pick it up?

Thanks,
Jason