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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: PUZP153MB0749.APCP153.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-Network-Message-Id: 78184e62-bb71-45c3-4f68-08db6570fc97 X-MS-Exchange-CrossTenant-originalarrivaltime: 05 Jun 2023 03:00:15.1494 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: N+eMhoViTxQtJLvGNtT2ODKHXC/VCxzl6tHMuGKY3toa+GBotQn+18nmQbtue2fe3xCRfg9lkhBkfPIZUWO0qg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SG2P153MB0378 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org > -----Original Message----- > From: Greg KH > Sent: Sunday, June 4, 2023 12:40 PM > To: Saurabh Sengar > Cc: KY Srinivasan ; Haiyang Zhang > ; wei.liu@kernel.org; Dexuan Cui > ; Michael Kelley (LINUX) ; > linux-kernel@vger.kernel.org; linux-hyperv@vger.kernel.org > Subject: [EXTERNAL] Re: [PATCH 1/5] uio: Add hv_vmbus_client driver >=20 > On Fri, Jun 02, 2023 at 12:57:05AM -0700, Saurabh Sengar wrote: > > + * Since the driver does not declare any device ids, you must > > + allocate > > + * id and bind the device to the driver yourself. For example: > > + * driverctl -b vmbus set-override uio_hv_vmbus_client >=20 > Shouldn't this be documented somewhere? I will update it in Documentation/driver-api/uio-howto.rst. > =09 > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#define DRIVER_VERSION "0.0.1" >=20 > Why this number? Why not "1"? >=20 > The whole "driver version" thing doesn't really make sense here, we shoul= d > just drop it from the uio later, right? will remove in V2. >=20 > > +#define DRIVER_AUTHOR "Saurabh Sengar " > > +#define DRIVER_DESC "Generic UIO driver for low speed VMBus > devices" > > + > > +#define DEFAULT_HV_RING_SIZE VMBUS_RING_SIZE(3 * > HV_HYP_PAGE_SIZE) > > +static int ring_size =3D DEFAULT_HV_RING_SIZE; > > + > > +struct uio_hv_vmbus_dev { > > + struct uio_info info; > > + struct hv_device *device; > > + atomic_t refcnt; >=20 > Why is this refcnt needed? >=20 > Have you seen the other threads about how attempting to block multiple > opens in UIO drivers really does not work at all? Please drop all of tha= t logic, > it is not correct. >=20 Will remove. >=20 > > +static ssize_t ring_size_show(struct device *dev, struct device_attrib= ute > *attr, > > + char *buf) > > +{ > > + return scnprintf(buf, PAGE_SIZE, "%d\n", ring_size); >=20 > Did you use checkpatch? >=20 > It should have said to use sysfs_emit(), right? Yes, I am using "--strict" switch for checkpatch.pl, still didn't get this= warning. However, I will use sysfs_emit() in V2. >=20 > > + ret =3D sysfs_create_file(&dev->device.kobj, > > +&dev_attr_ring_size.attr); >=20 > If you ever have to use a sysfs_* call in a driver, that's a huge hint so= mething > is wrong. Please fix this to not race with userspace and loose. Thanks for pointing this out, will look into this. >=20 > > + if (ret) > > + dev_notice(&dev->device, "sysfs create ring size file failed; > > +%d\n", ret); >=20 > Why not just use dev_err() for this and other errors? Why "notice"? Will fix. >=20 > > +MODULE_VERSION(DRIVER_VERSION); >=20 > This means nothing, please drop. OK. Thanks for review. - Saurabh >=20 > thanks, >=20 > greg k-h