Merge tag 'drm-misc-fixes-2018-02-21' of git://anongit.freedesktop.org/drm/drm-misc...

Fixes for 4.16. I contains fixes for deadlock on runtime suspend on few
drivers, a memory leak on non-blocking commits, a crash on color-eviction.
The is also meson and edid fixes, plus a fix for a doc warning.

* tag 'drm-misc-fixes-2018-02-21' of git://anongit.freedesktop.org/drm/drm-misc:
  drm/tve200: fix kernel-doc documentation comment include
  drm/meson: fix vsync buffer update
  drm: Handle unexpected holes in color-eviction
  drm/edid: Add 6 bpc quirk for CPT panel in Asus UX303LA
  drm/amdgpu: Fix deadlock on runtime suspend
  drm/radeon: Fix deadlock on runtime suspend
  drm/nouveau: Fix deadlock on runtime suspend
  drm: Allow determining if current task is output poll worker
  workqueue: Allow retrieval of current task's work struct
  drm/atomic: Fix memleak on ERESTARTSYS during non-blocking commits

diff --git a/Documentation/gpu/tve200.rst b/Documentation/gpu/tve200.rst
index 69b17b3..152ea93 100644 (file)
--- a/Documentation/gpu/tve200.rst
+++ b/Documentation/gpu/tve200.rst
@@ -3,4 +3,4 @@
 ==================================
 
 .. kernel-doc:: drivers/gpu/drm/tve200/tve200_drv.c
-   :doc: Faraday TV Encoder 200
+   :doc: Faraday TV Encoder TVE200 DRM Driver

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index 8ca3783..74d2efa 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -736,9 +736,11 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        int r;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (encoder) {
                struct amdgpu_encoder *amdgpu_encoder = to_amdgpu_encoder(encoder);
@@ -757,8 +759,12 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
        /* check acpi lid status ??? */
 
        amdgpu_connector_update_scratch_regs(connector, ret);
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
+
        return ret;
 }
 
@@ -868,9 +874,11 @@ amdgpu_connector_vga_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        int r;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        encoder = amdgpu_connector_best_single_encoder(connector);
        if (!encoder)
@@ -924,8 +932,10 @@ amdgpu_connector_vga_detect(struct drm_connector *connector, bool force)
        amdgpu_connector_update_scratch_regs(connector, ret);
 
 out:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }
@@ -988,9 +998,11 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        bool dret = false, broken_edid = false;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
                ret = connector->status;
@@ -1115,8 +1127,10 @@ out:
        amdgpu_connector_update_scratch_regs(connector, ret);
 
 exit:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }
@@ -1359,9 +1373,11 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
        struct drm_encoder *encoder = amdgpu_connector_best_single_encoder(connector);
        int r;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
                ret = connector->status;
@@ -1429,8 +1445,10 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
 
        amdgpu_connector_update_scratch_regs(connector, ret);
 out:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index ab40321..ae3cbfe 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1878,6 +1878,8 @@ int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
                new_crtc_state->event->base.completion = &commit->flip_done;
                new_crtc_state->event->base.completion_release = release_crtc_commit;
                drm_crtc_commit_get(commit);
+
+               commit->abort_completion = true;
        }
 
        for_each_oldnew_connector_in_state(state, conn, old_conn_state, new_conn_state, i) {
@@ -3421,8 +3423,21 @@ EXPORT_SYMBOL(drm_atomic_helper_crtc_duplicate_state);
 void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc_state *state)
 {
        if (state->commit) {
+               /*
+                * In the event that a non-blocking commit returns
+                * -ERESTARTSYS before the commit_tail work is queued, we will
+                * have an extra reference to the commit object. Release it, if
+                * the event has not been consumed by the worker.
+                *
+                * state->event may be freed, so we can't directly look at
+                * state->event->base.completion.
+                */
+               if (state->event && state->commit->abort_completion)
+                       drm_crtc_commit_put(state->commit);
+
                kfree(state->commit->event);
                state->commit->event = NULL;
+
                drm_crtc_commit_put(state->commit);
        }
 

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 9796c29..4f751a9 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -113,6 +113,9 @@ static const struct edid_quirk {
        /* AEO model 0 reports 8 bpc, but is a 6 bpc panel */
        { "AEO", 0, EDID_QUIRK_FORCE_6BPC },
 
+       /* CPT panel of Asus UX303LA reports 8 bpc, but is a 6 bpc panel */
+       { "CPT", 0x17df, EDID_QUIRK_FORCE_6BPC },
+
        /* Belinea 10 15 55 */
        { "MAX", 1516, EDID_QUIRK_PREFER_LARGE_60 },
        { "MAX", 0x77e, EDID_QUIRK_PREFER_LARGE_60 },

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 186c4e9..89eef1b 100644 (file)
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -836,9 +836,24 @@ struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
        if (!mm->color_adjust)
                return NULL;
 
-       hole = list_first_entry(&mm->hole_stack, typeof(*hole), hole_stack);
-       hole_start = __drm_mm_hole_node_start(hole);
-       hole_end = hole_start + hole->hole_size;
+       /*
+        * The hole found during scanning should ideally be the first element
+        * in the hole_stack list, but due to side-effects in the driver it
+        * may not be.
+        */
+       list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
+               hole_start = __drm_mm_hole_node_start(hole);
+               hole_end = hole_start + hole->hole_size;
+
+               if (hole_start <= scan->hit_start &&
+                   hole_end >= scan->hit_end)
+                       break;
+       }
+
+       /* We should only be called after we found the hole previously */
+       DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
+       if (unlikely(&hole->hole_stack == &mm->hole_stack))
+               return NULL;
 
        DRM_MM_BUG_ON(hole_start > scan->hit_start);
        DRM_MM_BUG_ON(hole_end < scan->hit_end);

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 555fbe5..00b8445 100644 (file)
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -653,6 +653,26 @@ out:
                schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
 }
 
+/**
+ * drm_kms_helper_is_poll_worker - is %current task an output poll worker?
+ *
+ * Determine if %current task is an output poll worker.  This can be used
+ * to select distinct code paths for output polling versus other contexts.
+ *
+ * One use case is to avoid a deadlock between the output poll worker and
+ * the autosuspend worker wherein the latter waits for polling to finish
+ * upon calling drm_kms_helper_poll_disable(), while the former waits for
+ * runtime suspend to finish upon calling pm_runtime_get_sync() in a
+ * connector ->detect hook.
+ */
+bool drm_kms_helper_is_poll_worker(void)
+{
+       struct work_struct *work = current_work();
+
+       return work && work->func == output_poll_execute;
+}
+EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
+
 /**
  * drm_kms_helper_poll_disable - disable output polling
  * @dev: drm_device

diff --git a/drivers/gpu/drm/meson/meson_crtc.c b/drivers/gpu/drm/meson/meson_crtc.c
index 5155f01..0552020 100644 (file)
--- a/drivers/gpu/drm/meson/meson_crtc.c
+++ b/drivers/gpu/drm/meson/meson_crtc.c
@@ -36,6 +36,7 @@
 #include "meson_venc.h"
 #include "meson_vpp.h"
 #include "meson_viu.h"
+#include "meson_canvas.h"
 #include "meson_registers.h"
 
 /* CRTC definition */
@@ -192,6 +193,11 @@ void meson_crtc_irq(struct meson_drm *priv)
                } else
                        meson_vpp_disable_interlace_vscaler_osd1(priv);
 
+               meson_canvas_setup(priv, MESON_CANVAS_ID_OSD1,
+                          priv->viu.osd1_addr, priv->viu.osd1_stride,
+                          priv->viu.osd1_height, MESON_CANVAS_WRAP_NONE,
+                          MESON_CANVAS_BLKMODE_LINEAR);
+
                /* Enable OSD1 */
                writel_bits_relaxed(VPP_OSD1_POSTBLEND, VPP_OSD1_POSTBLEND,
                                    priv->io_base + _REG(VPP_MISC));

diff --git a/drivers/gpu/drm/meson/meson_drv.h b/drivers/gpu/drm/meson/meson_drv.h
index 5e8b392..8450d6a 100644 (file)
--- a/drivers/gpu/drm/meson/meson_drv.h
+++ b/drivers/gpu/drm/meson/meson_drv.h
@@ -43,6 +43,9 @@ struct meson_drm {
                bool osd1_commit;
                uint32_t osd1_ctrl_stat;
                uint32_t osd1_blk0_cfg[5];
+               uint32_t osd1_addr;
+               uint32_t osd1_stride;
+               uint32_t osd1_height;
        } viu;
 
        struct {

diff --git a/drivers/gpu/drm/meson/meson_plane.c b/drivers/gpu/drm/meson/meson_plane.c
index d0a6ac8..27bd350 100644 (file)
--- a/drivers/gpu/drm/meson/meson_plane.c
+++ b/drivers/gpu/drm/meson/meson_plane.c
@@ -164,10 +164,9 @@ static void meson_plane_atomic_update(struct drm_plane *plane,
        /* Update Canvas with buffer address */
        gem = drm_fb_cma_get_gem_obj(fb, 0);
 
-       meson_canvas_setup(priv, MESON_CANVAS_ID_OSD1,
-                          gem->paddr, fb->pitches[0],
-                          fb->height, MESON_CANVAS_WRAP_NONE,
-                          MESON_CANVAS_BLKMODE_LINEAR);
+       priv->viu.osd1_addr = gem->paddr;
+       priv->viu.osd1_stride = fb->pitches[0];
+       priv->viu.osd1_height = fb->height;
 
        spin_unlock_irqrestore(&priv->drm->event_lock, flags);
 }

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 69d6e61..6ed9cb0 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -570,9 +570,15 @@ nouveau_connector_detect(struct drm_connector *connector, bool force)
                nv_connector->edid = NULL;
        }
 
-       ret = pm_runtime_get_sync(connector->dev->dev);
-       if (ret < 0 && ret != -EACCES)
-               return conn_status;
+       /* Outputs are only polled while runtime active, so acquiring a
+        * runtime PM ref here is unnecessary (and would deadlock upon
+        * runtime suspend because it waits for polling to finish).
+        */
+       if (!drm_kms_helper_is_poll_worker()) {
+               ret = pm_runtime_get_sync(connector->dev->dev);
+               if (ret < 0 && ret != -EACCES)
+                       return conn_status;
+       }
 
        nv_encoder = nouveau_connector_ddc_detect(connector);
        if (nv_encoder && (i2c = nv_encoder->i2c) != NULL) {
@@ -647,8 +653,10 @@ detect_analog:
 
  out:
 
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return conn_status;
 }

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 5012f5e..2e2ca3c 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -899,9 +899,11 @@ radeon_lvds_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        int r;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (encoder) {
                struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
@@ -924,8 +926,12 @@ radeon_lvds_detect(struct drm_connector *connector, bool force)
        /* check acpi lid status ??? */
 
        radeon_connector_update_scratch_regs(connector, ret);
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
+
        return ret;
 }
 
@@ -1039,9 +1045,11 @@ radeon_vga_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        int r;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        encoder = radeon_best_single_encoder(connector);
        if (!encoder)
@@ -1108,8 +1116,10 @@ radeon_vga_detect(struct drm_connector *connector, bool force)
        radeon_connector_update_scratch_regs(connector, ret);
 
 out:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }
@@ -1173,9 +1183,11 @@ radeon_tv_detect(struct drm_connector *connector, bool force)
        if (!radeon_connector->dac_load_detect)
                return ret;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        encoder = radeon_best_single_encoder(connector);
        if (!encoder)
@@ -1187,8 +1199,12 @@ radeon_tv_detect(struct drm_connector *connector, bool force)
        if (ret == connector_status_connected)
                ret = radeon_connector_analog_encoder_conflict_solve(connector, encoder, ret, false);
        radeon_connector_update_scratch_regs(connector, ret);
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
+
        return ret;
 }
 
@@ -1251,9 +1267,11 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
        enum drm_connector_status ret = connector_status_disconnected;
        bool dret = false, broken_edid = false;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (radeon_connector->detected_hpd_without_ddc) {
                force = true;
@@ -1436,8 +1454,10 @@ out:
        }
 
 exit:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }
@@ -1688,9 +1708,11 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
        if (radeon_dig_connector->is_mst)
                return connector_status_disconnected;
 
-       r = pm_runtime_get_sync(connector->dev->dev);
-       if (r < 0)
-               return connector_status_disconnected;
+       if (!drm_kms_helper_is_poll_worker()) {
+               r = pm_runtime_get_sync(connector->dev->dev);
+               if (r < 0)
+                       return connector_status_disconnected;
+       }
 
        if (!force && radeon_check_hpd_status_unchanged(connector)) {
                ret = connector->status;
@@ -1777,8 +1799,10 @@ radeon_dp_detect(struct drm_connector *connector, bool force)
        }
 
 out:
-       pm_runtime_mark_last_busy(connector->dev->dev);
-       pm_runtime_put_autosuspend(connector->dev->dev);
+       if (!drm_kms_helper_is_poll_worker()) {
+               pm_runtime_mark_last_busy(connector->dev->dev);
+               pm_runtime_put_autosuspend(connector->dev->dev);
+       }
 
        return ret;
 }

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 1c27526..cf13842 100644 (file)
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -134,6 +134,15 @@ struct drm_crtc_commit {
         * &drm_pending_vblank_event pointer to clean up private events.
         */
        struct drm_pending_vblank_event *event;
+
+       /**
+        * @abort_completion:
+        *
+        * A flag that's set after drm_atomic_helper_setup_commit takes a second
+        * reference for the completion of $drm_crtc_state.event. It's used by
+        * the free code to remove the second reference if commit fails.
+        */
+       bool abort_completion;
 };
 
 struct __drm_planes_state {

diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h
index 76e237b..6914633 100644 (file)
--- a/include/drm/drm_crtc_helper.h
+++ b/include/drm/drm_crtc_helper.h
@@ -77,5 +77,6 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev);
 
 void drm_kms_helper_poll_disable(struct drm_device *dev);
 void drm_kms_helper_poll_enable(struct drm_device *dev);
+bool drm_kms_helper_is_poll_worker(void);
 
 #endif

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 4a54ef9..bc0cda1 100644 (file)
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -465,6 +465,7 @@ extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 
 extern void workqueue_set_max_active(struct workqueue_struct *wq,
                                     int max_active);
+extern struct work_struct *current_work(void);
 extern bool current_is_workqueue_rescuer(void);
 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 extern unsigned int work_busy(struct work_struct *work);

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 017044c..bb9a519 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4179,6 +4179,22 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
 }
 EXPORT_SYMBOL_GPL(workqueue_set_max_active);
 
+/**
+ * current_work - retrieve %current task's work struct
+ *
+ * Determine if %current task is a workqueue worker and what it's working on.
+ * Useful to find out the context that the %current task is running in.
+ *
+ * Return: work struct if %current task is a workqueue worker, %NULL otherwise.
+ */
+struct work_struct *current_work(void)
+{
+       struct worker *worker = current_wq_worker();
+
+       return worker ? worker->current_work : NULL;
+}
+EXPORT_SYMBOL(current_work);
+
 /**
  * current_is_workqueue_rescuer - is %current workqueue rescuer?
  *