Chris Wilson 5a198b8c53 drm/i915: Do not overwrite the request with zero on reallocation ... When using RCU lookup for the request, commit 0eafec6d32 ("drm/i915: Enable lockless lookup of request tracking via RCU"), we acknowledge that we may race with another thread that could have reallocated the request. In order for the first thread not to blow up, the second thread must not clear the request completed before overwriting it. In the RCU lookup, we allow for the engine/seqno to be replaced but we do not allow for it to be zeroed. The choice we make is to either add extra checking to the RCU lookup, or embrace the inherent races (as intended). It is more complicated as we need to manually clear everything we depend upon being zero initialised, but we benefit from not emiting the memset() to clear the entire frequently allocated structure (that memset turns up in throughput profiles). And at the same time, the lookup remains flexible for future adjustments. v2: Old style LRC requires another variable to be initialize. (The danger inherent in not zeroing everything.) v3: request->batch also needs to be cleared v4: signaling.tsk is no long used unset, but pid still exists Fixes: 0eafec6d32 ("drm/i915: Enable lockless lookup of request...") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: "Goel, Akash" <akash.goel@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1470731014-6894-2-git-send-email-chris@chris-wilson.co.uk		2016-08-09 10:17:27 +01:00
..
amd	drm/amd/powerplay: remove enable_clock_power_gatings_tasks from initialize and resume events	2016-07-29 14:37:13 -04:00
arc	drm/arc: Remove redundant dev_err call in arcpgu_load()	2016-07-19 15:33:50 -04:00
arm	drm/arm: mali-dp: Fix error return code in malidp_bind()	2016-07-28 12:59:56 +02:00
armada	drm/armada: make fbdev support really optional	2016-07-18 09:11:33 +02:00
ast	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
atmel-hlcdc	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
bochs	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
bridge	Merge tag 'topic/drm-misc-2016-07-28' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-30 05:26:07 +10:00
cirrus	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
etnaviv	drm/etnaviv: Optimize error handling in etnaviv_gem_new_userptr()	2016-07-22 13:51:49 -04:00
exynos	GPU-DRM-Exynos: Delete an unnecessary check before the function call "vunmap"	2016-07-21 14:06:33 -04:00
fsl-dcu	Merge tag 'topic/drm-misc-2016-07-22' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-27 10:33:08 +10:00
gma500	drm/gma500: remove unnecessary stub for fb_ioctl()	2016-07-28 10:04:03 +02:00
hisilicon	drm/hisilicon: Fix ADE vblank on/off handling	2016-07-12 14:17:03 +02:00
i2c	drm/i2c: adv7511: Move to bridge folder	2016-07-13 14:24:35 +05:30
i810
i915	drm/i915: Do not overwrite the request with zero on reallocation	2016-08-09 10:17:27 +01:00
imx	imx-drm ldb mode set fix	2016-07-30 05:45:30 +10:00
mediatek	Merge tag 'topic/drm-misc-2016-07-14' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-15 11:01:37 +10:00
mga
mgag200	drm/mgag200: Delete an unnecessary check before drm_gem_object_unreference_unlocked()	2016-07-22 11:23:39 -04:00
msm	drm/msm: Delete an unnecessary check before drm_gem_object_unreference()	2016-07-16 10:29:35 -04:00
nouveau	Merge tag 'topic/drm-misc-2016-07-22' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-27 10:33:08 +10:00
omapdrm	GPU-DRM-OMAP: Delete unnecessary checks before two function calls	2016-07-22 10:27:59 +02:00
panel	drm/panel: simple: Add support for Starry KR122EA0SRA panel	2016-07-11 14:30:43 +02:00
qxl	drm/qxl: Delete an unnecessary check before drm_gem_object_unreference_unlocked()	2016-07-22 11:23:39 -04:00
r128
radeon	drm/radeon: Remove deprecated create_singlethread_workqueue	2016-07-29 14:36:55 -04:00
rcar-du	Merge tag 'topic/drm-misc-2016-07-22' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-27 10:33:08 +10:00
rockchip	Merge tag 'topic/drm-misc-2016-07-22' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-27 10:33:08 +10:00
savage
shmobile	drm/shmobile: make fbdev support really optional	2016-07-18 09:11:37 +02:00
sis
sti	drm/sti: use new Reset API	2016-07-26 10:25:00 -04:00
sun4i	Merge tag 'topic/drm-misc-2016-07-22' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-27 10:33:08 +10:00
tdfx
tegra	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
tilcdc	drm/tilcdc: make fbdev support really optional	2016-07-18 09:11:38 +02:00
ttm	drm/ttm: partial revert "cleanup ttm_tt_(unbind|destroy)" v3	2016-07-29 14:37:04 -04:00
udl	drm/udl: make fbdev support really optional	2016-07-18 09:11:40 +02:00
vc4	Merge remote-tracking branch 'airlied/drm-next' into topic/drm-misc	2016-07-19 09:27:29 +02:00
vgem	drm/vgem: Fix non static symbol warning	2016-07-19 15:01:52 +02:00
via
virtio	drm/virtio: Fix non static symbol warning	2016-07-19 15:44:10 -04:00
vmwgfx	Merge tag 'topic/drm-misc-2016-07-28' of git://anongit.freedesktop.org/drm-intel into drm-next	2016-07-30 05:26:07 +10:00
ati_pcigart.c
drm_agpsupport.c
drm_atomic_helper.c
drm_atomic.c	drm/atomic: Delete an unnecessary check before drm_property_unreference_blob()	2016-07-20 13:23:39 -04:00
drm_auth.c	drm: document drm_auth.c	2016-06-21 22:10:55 +02:00
drm_bridge.c
drm_bufs.c
drm_cache.c	drm: Restore double clflush on the last partial cacheline	2016-07-12 15:57:13 +02:00
drm_context.c
drm_crtc_helper.c	Linux 4.7-rc5	2016-07-02 15:56:01 +10:00
drm_crtc_internal.h	Revert "drm: Resurrect atomic rmfb code"	2016-07-14 15:18:15 +02:00
drm_crtc.c	drm: drm_connector->s/connector_id/index/ for consistency	2016-07-19 21:51:17 +02:00
drm_debugfs.c
drm_dma.c
drm_dp_aux_dev.c	drm_aux-dev: fix error handling in drm_dp_aux_dev_init()	2016-07-12 14:10:57 +02:00
drm_dp_dual_mode_helper.c
drm_dp_helper.c	drm: aux ->transfer() can return 0, deal with it	2016-07-29 14:13:03 +10:00
drm_dp_mst_topology.c	drm/dp-mst: Missing kernel doc	2016-07-19 10:31:53 +02:00
drm_drv.c	drm: Do a full device unregister when unplugging	2016-07-12 13:01:49 +02:00
drm_edid_load.c
drm_edid.c
drm_encoder_slave.c
drm_fb_cma_helper.c	Merge branch 'for-next' of http://git.agner.ch/git/linux-drm-fsl-dcu into drm-next	2016-07-02 16:21:35 +10:00
drm_fb_helper.c	drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference	2016-06-22 10:07:28 +02:00
drm_flip_work.c
drm_fops.c	drm: Clean up drm_crtc.h	2016-06-21 21:43:28 +02:00
drm_fourcc.c
drm_gem_cma_helper.c
drm_gem.c
drm_global.c
drm_hashtab.c
drm_info.c	drm: Extract drm_is_current_master	2016-06-21 21:58:12 +02:00
drm_internal.h	drm: Nuke SET_UNIQUE ioctl	2016-06-21 21:43:46 +02:00
drm_ioc32.c
drm_ioctl.c	drm: Don't overwrite user ioctl arg unless requested	2016-07-14 10:12:50 +02:00
drm_irq.c	drm: Extract&Document drm_irq.h	2016-07-19 10:29:47 +02:00
drm_kms_helper_common.c
drm_legacy.h
drm_lock.c	drm: Extract drm_is_current_master	2016-06-21 21:58:12 +02:00
drm_memory.c	drm: Fix broken use of _PAGE_NO_CACHE on powerpc	2016-07-12 13:20:39 +02:00
drm_mipi_dsi.c	drm/dsi: Make set_tear_scanline command consistent	2016-07-12 13:19:26 +02:00
drm_mm.c
drm_modes.c
drm_modeset_lock.c
drm_of.c
drm_panel.c
drm_pci.c	drm: Nuke SET_UNIQUE ioctl	2016-06-21 21:43:46 +02:00
drm_plane_helper.c
drm_platform.c	drm: Lobotomize set_busid nonsense for !pci drivers	2016-06-21 21:56:23 +02:00
drm_prime.c
drm_probe_helper.c
drm_rect.c
drm_scatter.c	drm: Fix broken use of _PAGE_NO_CACHE on powerpc	2016-07-12 13:20:39 +02:00
drm_simple_kms_helper.c
drm_sysfs.c
drm_trace_points.c
drm_trace.h
drm_vm.c	drm: Fix broken use of _PAGE_NO_CACHE on powerpc	2016-07-12 13:20:39 +02:00
drm_vma_manager.c
Kconfig
Makefile