From 58374713c9dfb4d231f8c56cac089f6fbdedc2ec Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 10 Jul 2010 23:51:39 +0200 Subject: drm: kill BKL from common code This restricts the use of the big kernel lock to the i830 and i810 device drivers. The three remaining users in common code (open, ioctl and release) get converted to a new mutex, the drm_global_mutex, making the locking stricter than the big kernel lock. This may have a performance impact, but only in those cases that currently don't use DRM_UNLOCKED flag in the ioctl list and would benefit from that anyway. The reason why i810 and i830 cannot use drm_global_mutex in their mmap functions is a lock-order inversion problem between the current use of the BKL and mmap_sem in these drivers. Since the BKL has release-on-sleep semantics, it's harmless but it would cause trouble if we replace the BKL with a mutex. Instead, these drivers get their own ioctl wrappers that take the BKL around every ioctl call and then set their own handlers as DRM_UNLOCKED. Signed-off-by: Arnd Bergmann Cc: David Airlie Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie --- drivers/gpu/drm/i830/i830_dma.c | 42 +++++++++++++++++++++++++++-------------- drivers/gpu/drm/i830/i830_drv.c | 2 +- drivers/gpu/drm/i830/i830_drv.h | 1 + 3 files changed, 30 insertions(+), 15 deletions(-) (limited to 'drivers/gpu/drm/i830') diff --git a/drivers/gpu/drm/i830/i830_dma.c b/drivers/gpu/drm/i830/i830_dma.c index 7ee85ea507ce..5168862c9227 100644 --- a/drivers/gpu/drm/i830/i830_dma.c +++ b/drivers/gpu/drm/i830/i830_dma.c @@ -36,6 +36,7 @@ #include "i830_drm.h" #include "i830_drv.h" #include /* For task queue support */ +#include #include #include #include @@ -1509,21 +1510,34 @@ int i830_driver_dma_quiescent(struct drm_device *dev) return 0; } +/* + * call the drm_ioctl under the big kernel lock because + * to lock against the i830_mmap_buffers function. + */ +long i830_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret; + lock_kernel(); + ret = drm_ioctl(file, cmd, arg); + unlock_kernel(); + return ret; +} + struct drm_ioctl_desc i830_ioctls[] = { - DRM_IOCTL_DEF(DRM_I830_INIT, i830_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY), - DRM_IOCTL_DEF(DRM_I830_VERTEX, i830_dma_vertex, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_CLEAR, i830_clear_bufs, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_FLUSH, i830_flush_ioctl, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_GETAGE, i830_getage, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_GETBUF, i830_getbuf, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_SWAP, i830_swap_bufs, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_COPY, i830_copybuf, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_DOCOPY, i830_docopy, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_FLIP, i830_flip_bufs, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_IRQ_EMIT, i830_irq_emit, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_IRQ_WAIT, i830_irq_wait, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_GETPARAM, i830_getparam, DRM_AUTH), - DRM_IOCTL_DEF(DRM_I830_SETPARAM, i830_setparam, DRM_AUTH) + DRM_IOCTL_DEF(DRM_I830_INIT, i830_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_VERTEX, i830_dma_vertex, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_CLEAR, i830_clear_bufs, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_FLUSH, i830_flush_ioctl, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_GETAGE, i830_getage, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_GETBUF, i830_getbuf, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_SWAP, i830_swap_bufs, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_COPY, i830_copybuf, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_DOCOPY, i830_docopy, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_FLIP, i830_flip_bufs, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_IRQ_EMIT, i830_irq_emit, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_IRQ_WAIT, i830_irq_wait, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_GETPARAM, i830_getparam, DRM_AUTH|DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_I830_SETPARAM, i830_setparam, DRM_AUTH|DRM_UNLOCKED), }; int i830_max_ioctl = DRM_ARRAY_SIZE(i830_ioctls); diff --git a/drivers/gpu/drm/i830/i830_drv.c b/drivers/gpu/drm/i830/i830_drv.c index 44f990bed8f4..a5c66aa82f0c 100644 --- a/drivers/gpu/drm/i830/i830_drv.c +++ b/drivers/gpu/drm/i830/i830_drv.c @@ -70,7 +70,7 @@ static struct drm_driver driver = { .owner = THIS_MODULE, .open = drm_open, .release = drm_release, - .unlocked_ioctl = drm_ioctl, + .unlocked_ioctl = i830_ioctl, .mmap = drm_mmap, .poll = drm_poll, .fasync = drm_fasync, diff --git a/drivers/gpu/drm/i830/i830_drv.h b/drivers/gpu/drm/i830/i830_drv.h index ecfd25a35da3..0df1c720560b 100644 --- a/drivers/gpu/drm/i830/i830_drv.h +++ b/drivers/gpu/drm/i830/i830_drv.h @@ -122,6 +122,7 @@ typedef struct drm_i830_private { } drm_i830_private_t; +long i830_ioctl(struct file *file, unsigned int cmd, unsigned long arg); extern struct drm_ioctl_desc i830_ioctls[]; extern int i830_max_ioctl; -- cgit v1.2.3