drm_getclient, drm_getstats and drm_getmap (with a few minor adjustments) do not need global mutex, so fix that and make the said ioctls DRM_UNLOCKED. Details:

drm_getclient: the only thing that should be protected here is dev->filelist and that is already protected everywhere with dev->struct_mutex.

drm_getstats: there is no need for any mutex here because the loop runs through quasi-static (set at load time only) data, and the actual count access is done with atomic_read()

drm_getmap already uses dev->struct_mutex to protect dev->maplist, which also used to protect the same structure everywhere else except at three places: * drm_getsarea, which doesn't grab *any* mutex before touching dev->maplist (so no drm_global_mutex doesn't help here either; different issue for a different patch). However, drivers seem to call it only at initialization time so it probably doesn't matter * drm_master_destroy, which is called from drm_master_put, which in turn is protected with dev->struct_mutex everywhere else in drm module, so we are good here too. * drm_getsareactx, which releases the dev->struct_mutex too early, but this patch includes the fix for that.

v2: * incorporate comments received from Daniel Vetter * include the (long) explanation above to make it clear what we are doing (and why), also at Daniel Vetter's request * tighten up mutex grab/release locations to only encompass real critical sections, rather than some random code around them

Signed-off-by: Ilija Hadzic ihadzic@research.bell-labs.com --- drivers/gpu/drm/drm_context.c | 5 +++-- drivers/gpu/drm/drm_drv.c | 6 +++--- drivers/gpu/drm/drm_ioctl.c | 15 ++++----------- 3 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c index 6d440fb..325365f 100644 --- a/drivers/gpu/drm/drm_context.c +++ b/drivers/gpu/drm/drm_context.c @@ -154,8 +154,6 @@ int drm_getsareactx(struct drm_device *dev, void *data, return -EINVAL; }

- mutex_unlock(&dev->struct_mutex); - request->handle = NULL; list_for_each_entry(_entry, &dev->maplist, head) { if (_entry->map == map) { @@ -164,6 +162,9 @@ int drm_getsareactx(struct drm_device *dev, void *data, break; } } + + mutex_unlock(&dev->struct_mutex); + if (request->handle == NULL) return -EINVAL;

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index c990dab..dc0eb0b 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -64,9 +64,9 @@ static struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0), DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0), DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY), - DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_getmap, 0), - DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, 0), - DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, 0), + DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_getmap, DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, DRM_UNLOCKED), + DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, DRM_UNLOCKED), DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_UNLOCKED), DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER),

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 904d7e9..956fd38 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -158,14 +158,11 @@ int drm_getmap(struct drm_device *dev, void *data, int i;

idx = map->offset; - - mutex_lock(&dev->struct_mutex); - if (idx < 0) { - mutex_unlock(&dev->struct_mutex); + if (idx < 0) return -EINVAL; - }

i = 0; + mutex_lock(&dev->struct_mutex); list_for_each(list, &dev->maplist) { if (i == idx) { r_list = list_entry(list, struct drm_map_list, head); @@ -211,9 +208,9 @@ int drm_getclient(struct drm_device *dev, void *data, int i;

idx = client->idx; - mutex_lock(&dev->struct_mutex); - i = 0; + + mutex_lock(&dev->struct_mutex); list_for_each_entry(pt, &dev->filelist, lhead) { if (i++ >= idx) { client->auth = pt->authenticated; @@ -249,8 +246,6 @@ int drm_getstats(struct drm_device *dev, void *data,

memset(stats, 0, sizeof(*stats));

- mutex_lock(&dev->struct_mutex); - for (i = 0; i < dev->counters; i++) { if (dev->types[i] == _DRM_STAT_LOCK) stats->data[i].value = @@ -262,8 +257,6 @@ int drm_getstats(struct drm_device *dev, void *data,

stats->count = dev->counters;

- mutex_unlock(&dev->struct_mutex); - return 0; }