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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?cjcKusY9INUoNKQSbaGWTGvkfP98yGc1nNiF58oaXqaetg/3vwK5p6Mq8Qsp?= =?us-ascii?Q?HoQ00z/oAePYk9C+UQxHZ0gHYmuV9Xn0H11ZxxW1TxIuIvggvCwJhZmHkehR?= =?us-ascii?Q?8jc34Ax0Zy3BEV/KWiARkGpWrv2hBSJPGmCbA0+gUoXIqBczHCpezfCwDmk7?= =?us-ascii?Q?HL7+ky9TBAj+/elbn9es9hqPgBegXUJ4tkWONjZT62U/b09NPUHrwUW2vlkL?= =?us-ascii?Q?qLQ+X4NuQKIqHTbwPZHCLsMupFjCwXJgn5WXsFb91pCclHxgne9jVBYZcoul?= =?us-ascii?Q?RITyul2XyIyCfMmZs8OtRxXYuxTtyxrHvg82RLT03+/gMd+oFGAnLJXNzsfe?= =?us-ascii?Q?EzS55paeuyAqbo1adypovJO+Wh7AYliFaM8i9LeNIPKd5UtnkwB7ZdFf5VrJ?= =?us-ascii?Q?0bwRMBy03ZCb2D32j/KZuNMScRKMKHo2Vmx+GSDPQYp/30qIWEM+W3QEsAhb?= =?us-ascii?Q?xe2XbLzkN3pEiy1CuKtaAypX3q/BU5iG3g/vh/S/dEo2KYhzgjLWnC2xRW87?= =?us-ascii?Q?LKKA0I9avwPZd5odvh2jBP/f23MD/7V5WjP0DCPOayk6/bN6jusyNqeje/Z2?= =?us-ascii?Q?8Td3w0T8Osom0XWQe0ngGEuv9eNlCntQc1IA6RuEmVwsuL68MOGKTV4rQoZ0?= =?us-ascii?Q?h0H6/r8H4icWT3FBRc0w06mvQt6VR4XAoi0W5tfnVR5Dh57K0mXxMjg7fqhl?= =?us-ascii?Q?y2gztMM7lnmWRHaeGxhtaum4uIumm3rG8NJUOqr2+eMV+kIR5bLPw5LoICCn?= =?us-ascii?Q?eMz6BrtJ/nZOHLT90YwMLhyNXQENnouBFI1y1L/Wyy+Cg7d4pJrqqhyVcpGi?= =?us-ascii?Q?JEX6XGS06EYlpNA/qobwHVNRP9iQfQ/OIKorgbV2nMoy5jNlRJoZuEbIf0s8?= =?us-ascii?Q?xPTWvyU5gzaP9rXi5EByfoUyK8kmj/zeeXPBvygZFDa4l8cd0gBYlaDstmKP?= =?us-ascii?Q?FwmB0T1mOA6OZeQ4osy4qDzDyV0HLHajBTEt+CmTRW5NuOjSZyeURS78RGIp?= =?us-ascii?Q?aw8F6T4psF8TmNe6Ao5LNkoDLcNa+dUXyeVDlrRoEJBWNxwAJ2YewQvNWMft?= =?us-ascii?Q?hNzzLyMnbxXOmJMOR8amapT/XOdKivPNXmOilZO3bODRD140BV8yYkN2y4Gh?= =?us-ascii?Q?g2P1pr6OoiwDfVWfRFyicl/WaaBqo7wodHecrTI8qZz5EP92wO8U7OnCP6bG?= =?us-ascii?Q?BwXiInKecF04idn7Ii+iJJVejKzhLiyenj87OLt2BxLEbgDvC/1jOyn5nd0f?= =?us-ascii?Q?x1w7eQc9NAZ7/mRyh8UXwAx1VsQTmsbzToxuyMTZjPVqA4aMseJbcsJOAluH?= =?us-ascii?Q?JL4KMjCRz5BZwS4xRW8Wpwz3jD7eJxP73eHbK56uVdCFTPGo+2GWrg0NmhUl?= =?us-ascii?Q?KoMM60nUBAgDQk+KounanyC+AJq1RU6P4r8CMgw/2LjrfD5wnbMaah+R0LgK?= =?us-ascii?Q?amMBkoBmpvZanzAzI9QkFZmYmSR3MXXhXRk6xQVkOrc1Glvd+/c3hpJCIglZ?= =?us-ascii?Q?SvgdrXk/6sKa/CVZwVx+Oic5JZvE9UphuwVZ+AZssLHeUA96TqNiKYrR1jNm?= =?us-ascii?Q?dmgUdUPYk74Hr9cnYrmrsYMX7q0Zk3ihaTlqBJ0v+v1EDDRmVCTDxOHc9AnA?= =?us-ascii?Q?gg=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 0d02d93d-a17b-4279-75ae-08dbfd917b66 X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB8107.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Dec 2023 17:15:48.6873 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 8CGU+kjtSpxfJTBdAORZS3pBs8fsuY6lAwJaRKjUc63iYQtj/N4PL4Oz7LsDv/ZJu9MbrYYmLOFNhUCwTfmzgeBTAihUp9tMocC/oFwcOnQ= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR11MB6609 X-OriginatorOrg: intel.com Greg Kroah-Hartman wrote: > On Thu, Dec 14, 2023 at 10:25:27PM -0700, Vishal Verma wrote: > > Use the guard(device) macro to lock a 'struct device', and unlock it > > automatically when going out of scope using Scope Based Resource > > Management semantics. A lot of the sysfs attribute writes in > > drivers/dax/bus.c benefit from a cleanup using these, so change these > > where applicable. > > Wait, why are you needing to call device_lock() at all here? Why is dax > special in needing this when no other subsystem requires it? > > > > > Cc: Joao Martins > > Cc: Dan Williams > > Signed-off-by: Vishal Verma > > --- > > drivers/dax/bus.c | 143 ++++++++++++++++++++++-------------------------------- > > 1 file changed, 59 insertions(+), 84 deletions(-) > > > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > > index 1ff1ab5fa105..6226de131d17 100644 > > --- a/drivers/dax/bus.c > > +++ b/drivers/dax/bus.c > > @@ -294,13 +294,10 @@ static ssize_t available_size_show(struct device *dev, > > struct device_attribute *attr, char *buf) > > { > > struct dax_region *dax_region = dev_get_drvdata(dev); > > - unsigned long long size; > > > > - device_lock(dev); > > - size = dax_region_avail_size(dax_region); > > - device_unlock(dev); > > + guard(device)(dev); > > You have a valid device here, why are you locking it? How can it go > away? And if it can, shouldn't you have a local lock for it, and not > abuse the driver core lock? Yes, this is a driver-core lock abuse written by someone who should have known better. And yes, a local lock to protect the dax_region resource tree should replace this. A new rwsem to synchronize all list walks seems appropriate.