IDR is deprecated, and since XArray manages its own state with internal locking, it simplifies the locking on DRM side. Additionally, don't use the IRQ-safe variant, since operating on drm minor is not done in IRQ context. Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> Suggested-by: Matthew Wilcox <willy@xxxxxxxxxxxxx> --- This was originally sent as v4/v5 in larger series: https://lore.kernel.org/dri-devel/20220911211443.581481-2-michal.winiarski@xxxxxxxxx/ v1 -> v2: Fixed locking and corrected some misuse of XArray API (Matthew Wilcox) v2 -> v3: Store correct pointer, use xa_store rather than xa_cmpxchg (Oded Gabbay) drivers/gpu/drm/drm_drv.c | 51 ++++++++++++++------------------------- 1 file changed, 18 insertions(+), 33 deletions(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 8214a0b1ab7f..bdcdfeac76bf 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -34,6 +34,7 @@ #include <linux/pseudo_fs.h> #include <linux/slab.h> #include <linux/srcu.h> +#include <linux/xarray.h> #include <drm/drm_cache.h> #include <drm/drm_client.h> @@ -53,8 +54,7 @@ MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl"); MODULE_DESCRIPTION("DRM shared core routines"); MODULE_LICENSE("GPL and additional rights"); -static DEFINE_SPINLOCK(drm_minor_lock); -static struct idr drm_minors_idr; +static DEFINE_XARRAY_ALLOC(drm_minors_xa); /* * If the drm core fails to init for whatever reason, @@ -98,21 +98,19 @@ static struct drm_minor **drm_minor_get_slot(struct drm_device *dev, static void drm_minor_alloc_release(struct drm_device *dev, void *data) { struct drm_minor *minor = data; - unsigned long flags; WARN_ON(dev != minor->dev); put_device(minor->kdev); - spin_lock_irqsave(&drm_minor_lock, flags); - idr_remove(&drm_minors_idr, minor->index); - spin_unlock_irqrestore(&drm_minor_lock, flags); + xa_erase(&drm_minors_xa, minor->index); } +#define DRM_MINOR_LIMIT(t) ({ typeof(t) _t = (t); XA_LIMIT(64 * _t, 64 * _t + 63); }) + static int drm_minor_alloc(struct drm_device *dev, unsigned int type) { struct drm_minor *minor; - unsigned long flags; int r; minor = drmm_kzalloc(dev, sizeof(*minor), GFP_KERNEL); @@ -122,21 +120,10 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) minor->type = type; minor->dev = dev; - idr_preload(GFP_KERNEL); - spin_lock_irqsave(&drm_minor_lock, flags); - r = idr_alloc(&drm_minors_idr, - NULL, - 64 * type, - 64 * (type + 1), - GFP_NOWAIT); - spin_unlock_irqrestore(&drm_minor_lock, flags); - idr_preload_end(); - + r = xa_alloc(&drm_minors_xa, &minor->index, NULL, DRM_MINOR_LIMIT(type), GFP_KERNEL); if (r < 0) return r; - minor->index = r; - r = drmm_add_action_or_reset(dev, drm_minor_alloc_release, minor); if (r) return r; @@ -152,7 +139,7 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) static int drm_minor_register(struct drm_device *dev, unsigned int type) { struct drm_minor *minor; - unsigned long flags; + void *entry; int ret; DRM_DEBUG("\n"); @@ -172,9 +159,12 @@ static int drm_minor_register(struct drm_device *dev, unsigned int type) goto err_debugfs; /* replace NULL with @minor so lookups will succeed from now on */ - spin_lock_irqsave(&drm_minor_lock, flags); - idr_replace(&drm_minors_idr, minor, minor->index); - spin_unlock_irqrestore(&drm_minor_lock, flags); + entry = xa_store(&drm_minors_xa, minor->index, minor, GFP_KERNEL); + if (xa_is_err(entry)) { + ret = xa_err(entry); + goto err_debugfs; + } + WARN_ON(entry); DRM_DEBUG("new minor registered %d\n", minor->index); return 0; @@ -187,16 +177,13 @@ static int drm_minor_register(struct drm_device *dev, unsigned int type) static void drm_minor_unregister(struct drm_device *dev, unsigned int type) { struct drm_minor *minor; - unsigned long flags; minor = *drm_minor_get_slot(dev, type); if (!minor || !device_is_registered(minor->kdev)) return; /* replace @minor with NULL so lookups will fail from now on */ - spin_lock_irqsave(&drm_minor_lock, flags); - idr_replace(&drm_minors_idr, NULL, minor->index); - spin_unlock_irqrestore(&drm_minor_lock, flags); + xa_store(&drm_minors_xa, minor->index, NULL, GFP_KERNEL); device_del(minor->kdev); dev_set_drvdata(minor->kdev, NULL); /* safety belt */ @@ -215,13 +202,12 @@ static void drm_minor_unregister(struct drm_device *dev, unsigned int type) struct drm_minor *drm_minor_acquire(unsigned int minor_id) { struct drm_minor *minor; - unsigned long flags; - spin_lock_irqsave(&drm_minor_lock, flags); - minor = idr_find(&drm_minors_idr, minor_id); + xa_lock(&drm_minors_xa); + minor = xa_load(&drm_minors_xa, minor_id); if (minor) drm_dev_get(minor->dev); - spin_unlock_irqrestore(&drm_minor_lock, flags); + xa_unlock(&drm_minors_xa); if (!minor) { return ERR_PTR(-ENODEV); @@ -1037,7 +1023,7 @@ static void drm_core_exit(void) unregister_chrdev(DRM_MAJOR, "drm"); debugfs_remove(drm_debugfs_root); drm_sysfs_destroy(); - idr_destroy(&drm_minors_idr); + WARN_ON(!xa_empty(&drm_minors_xa)); drm_connector_ida_destroy(); } @@ -1046,7 +1032,6 @@ static int __init drm_core_init(void) int ret; drm_connector_ida_init(); - idr_init(&drm_minors_idr); drm_memcpy_init_early(); ret = drm_sysfs_init(); -- 2.38.1
