On Thu, Nov 3, 2022 at 7:26 AM Jiho Chu <jiho.chu@xxxxxxxxxxx> wrote: > > On Wed, 2 Nov 2022 22:34:04 +0200 > Oded Gabbay <ogabbay@xxxxxxxxxx> wrote: > > > +/** > > + * accel_open - open method for ACCEL file > > + * @inode: device inode > > + * @filp: file pointer. > > + * > > + * This function must be used by drivers as their &file_operations.open method. > > + * It looks up the correct ACCEL device and instantiates all the per-file > > + * resources for it. It also calls the &drm_driver.open driver callback. > > + * > > + * Return: 0 on success or negative errno value on failure. > > + */ > > +int accel_open(struct inode *inode, struct file *filp) > > +{ > > + struct drm_device *dev; > > + struct drm_minor *minor; > > + int retcode; > > + > > + minor = accel_minor_acquire(iminor(inode)); > > + if (IS_ERR(minor)) > > + return PTR_ERR(minor); > > + > > + dev = minor->dev; > > + > > + atomic_fetch_inc(&dev->open_count); > > + > > Hi, > It needs to consider drm_global_mutex to access open_count. > please check doxy of open_count. Now that I'm changing the code back to be part of drm.ko, I can return all the code that is in drm_copy which I removed for this to compile. > > > > + /* share address_space across all char-devs of a single device */ > > + filp->f_mapping = dev->anon_inode->i_mapping; > > + > > + retcode = drm_open_helper(filp, minor); > > + if (retcode) > > + goto err_undo; > > + > > + return 0; > > + > > +err_undo: > > + atomic_dec(&dev->open_count); > > + accel_minor_release(minor); > > + return retcode; > > +} > > +EXPORT_SYMBOL_GPL(accel_open); > > + > > static int accel_stub_open(struct inode *inode, struct file *filp) > > { > > - DRM_DEBUG("Operation not supported"); > > + const struct file_operations *new_fops; > > + struct drm_minor *minor; > > + int err; > > + > > + DRM_DEBUG("\n"); > > It seems useless. Correct, I removed it in v3. Thanks, Oded > > Thanks. > Jiho Chu