58374713c9
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 <arnd@arndb.de> Cc: David Airlie <airlied@linux.ie> Cc: dri-devel@lists.freedesktop.org Signed-off-by: Dave Airlie <airlied@redhat.com> |
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| Makefile | ||
| i810_dma.c | ||
| i810_drv.c | ||
| i810_drv.h | ||