On 3/22/2021 4:38 PM, Dan Williams wrote:
On Mon, Mar 22, 2021 at 4:32 PM Dave Jiang <dave.jiang@xxxxxxxxx> wrote:The char device setup and cleanup has device lifetime issues regarding when parts are initialized and cleaned up. The initialization of struct device is done incorrectly. device_initialize() needs to be called on the 'struct device' and then additional changes can be added. The ->release() function needs to be setup via device_type before dev_set_name() to allow proper cleanup. The change re-parents the cdev under the wq->conf_dev to get natural reference inheritance. No known dependency on the old device path exists. Reported-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland") Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>[..]diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c index 03079ff54889..8a08988ea9d1 100644 --- a/drivers/dma/idxd/sysfs.c +++ b/drivers/dma/idxd/sysfs.c @@ -1174,8 +1174,14 @@ static ssize_t wq_cdev_minor_show(struct device *dev, struct device_attribute *attr, char *buf) { struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev); + int minor = -1; - return sprintf(buf, "%d\n", wq->idxd_cdev.minor); + mutex_lock(&wq->wq_lock); + if (wq->idxd_cdev) + minor = wq->idxd_cdev->minor; + mutex_unlock(&wq->wq_lock); + + return sprintf(buf, "%d\n", minor);As I mentioned, let's not emit a negative value here. ...not that userspace should be using this awkward recreation of the existing core 'dev' attribute anyway. if (minor == -1) return -ENXIO; return sprintf(buf, "%d\n", minor);
Ok I'll update. This will go away when we convert to UACCE based driver.
