From: Rob Clark <robdcl...@chromium.org>

Replace the ww_mutex locking dance with the drm_exec helper.

v2: Error path fixes, move drm_exec_fini so we only call it once (and
    only if we have drm_exec_init()

Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 drivers/gpu/drm/msm/Kconfig          |   1 +
 drivers/gpu/drm/msm/msm_gem.h        |   5 +-
 drivers/gpu/drm/msm/msm_gem_submit.c | 119 +++++----------------------
 3 files changed, 24 insertions(+), 101 deletions(-)

diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
index 6309a857ca31..f91d87afc0d3 100644
--- a/drivers/gpu/drm/msm/Kconfig
+++ b/drivers/gpu/drm/msm/Kconfig
@@ -16,6 +16,7 @@ config DRM_MSM
        select DRM_DP_AUX_BUS
        select DRM_DISPLAY_DP_HELPER
        select DRM_DISPLAY_HELPER
+       select DRM_EXEC
        select DRM_KMS_HELPER
        select DRM_PANEL
        select DRM_BRIDGE
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index af884ced7a0d..7f34263048a3 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -9,6 +9,7 @@
 
 #include <linux/kref.h>
 #include <linux/dma-resv.h>
+#include "drm/drm_exec.h"
 #include "drm/gpu_scheduler.h"
 #include "msm_drv.h"
 
@@ -254,7 +255,7 @@ struct msm_gem_submit {
        struct msm_gpu *gpu;
        struct msm_gem_address_space *aspace;
        struct list_head node;   /* node in ring submit list */
-       struct ww_acquire_ctx ticket;
+       struct drm_exec exec;
        uint32_t seqno;         /* Sequence number of the submit on the ring */
 
        /* Hw fence, which is created when the scheduler executes the job, and
@@ -287,8 +288,6 @@ struct msm_gem_submit {
                struct drm_msm_gem_submit_reloc *relocs;
        } *cmd;  /* array of size nr_cmds */
        struct {
-/* make sure these don't conflict w/ MSM_SUBMIT_BO_x */
-#define BO_LOCKED      0x4000  /* obj lock is held */
                uint32_t flags;
                union {
                        struct drm_gem_object *obj;
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c 
b/drivers/gpu/drm/msm/msm_gem_submit.c
index 603f04d851d9..40878c26a749 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -248,85 +248,30 @@ static int submit_lookup_cmds(struct msm_gem_submit 
*submit,
        return ret;
 }
 
-static void submit_unlock_bo(struct msm_gem_submit *submit, int i)
-{
-       struct drm_gem_object *obj = submit->bos[i].obj;
-       unsigned cleanup_flags = BO_LOCKED;
-       unsigned flags = submit->bos[i].flags & cleanup_flags;
-
-       /*
-        * Clear flags bit before dropping lock, so that the msm_job_run()
-        * path isn't racing with submit_cleanup() (ie. the read/modify/
-        * write is protected by the obj lock in all paths)
-        */
-       submit->bos[i].flags &= ~cleanup_flags;
-
-       if (flags & BO_LOCKED)
-               dma_resv_unlock(obj->resv);
-}
-
 /* This is where we make sure all the bo's are reserved and pin'd: */
 static int submit_lock_objects(struct msm_gem_submit *submit)
 {
-       int contended, slow_locked = -1, i, ret = 0;
-
-retry:
-       for (i = 0; i < submit->nr_bos; i++) {
-               struct drm_gem_object *obj = submit->bos[i].obj;
-
-               if (slow_locked == i)
-                       slow_locked = -1;
+       int ret;
 
-               contended = i;
+       drm_exec_init(&submit->exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 
submit->nr_bos);
 
-               if (!(submit->bos[i].flags & BO_LOCKED)) {
-                       ret = dma_resv_lock_interruptible(obj->resv,
-                                                         &submit->ticket);
+       drm_exec_until_all_locked (&submit->exec) {
+               for (unsigned i = 0; i < submit->nr_bos; i++) {
+                       struct drm_gem_object *obj = submit->bos[i].obj;
+                       ret = drm_exec_prepare_obj(&submit->exec, obj, 1);
+                       drm_exec_retry_on_contention(&submit->exec);
                        if (ret)
-                               goto fail;
-                       submit->bos[i].flags |= BO_LOCKED;
+                               goto error;
                }
        }
 
-       ww_acquire_done(&submit->ticket);
-
        return 0;
 
-fail:
-       if (ret == -EALREADY) {
-               SUBMIT_ERROR(submit, "handle %u at index %u already on submit 
list\n",
-                            submit->bos[i].handle, i);
-               ret = -EINVAL;
-       }
-
-       for (; i >= 0; i--)
-               submit_unlock_bo(submit, i);
-
-       if (slow_locked > 0)
-               submit_unlock_bo(submit, slow_locked);
-
-       if (ret == -EDEADLK) {
-               struct drm_gem_object *obj = submit->bos[contended].obj;
-               /* we lost out in a seqno race, lock and retry.. */
-               ret = dma_resv_lock_slow_interruptible(obj->resv,
-                                                      &submit->ticket);
-               if (!ret) {
-                       submit->bos[contended].flags |= BO_LOCKED;
-                       slow_locked = contended;
-                       goto retry;
-               }
-
-               /* Not expecting -EALREADY here, if the bo was already
-                * locked, we should have gotten -EALREADY already from
-                * the dma_resv_lock_interruptable() call.
-                */
-               WARN_ON_ONCE(ret == -EALREADY);
-       }
-
+error:
        return ret;
 }
 
-static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
+static int submit_fence_sync(struct msm_gem_submit *submit)
 {
        int i, ret = 0;
 
@@ -334,22 +279,6 @@ static int submit_fence_sync(struct msm_gem_submit 
*submit, bool no_implicit)
                struct drm_gem_object *obj = submit->bos[i].obj;
                bool write = submit->bos[i].flags & MSM_SUBMIT_BO_WRITE;
 
-               /* NOTE: _reserve_shared() must happen before
-                * _add_shared_fence(), which makes this a slightly
-                * strange place to call it.  OTOH this is a
-                * convenient can-fail point to hook it in.
-                */
-               ret = dma_resv_reserve_fences(obj->resv, 1);
-               if (ret)
-                       return ret;
-
-               /* If userspace has determined that explicit fencing is
-                * used, it can disable implicit sync on the entire
-                * submit:
-                */
-               if (no_implicit)
-                       continue;
-
                /* Otherwise userspace can ask for implicit sync to be
                 * disabled on specific buffers.  This is useful for internal
                 * usermode driver managed buffers, suballocation, etc.
@@ -529,17 +458,14 @@ static int submit_reloc(struct msm_gem_submit *submit, 
struct drm_gem_object *ob
  */
 static void submit_cleanup(struct msm_gem_submit *submit, bool error)
 {
-       unsigned i;
-
-       if (error)
+       if (error) {
                submit_unpin_objects(submit);
-
-       for (i = 0; i < submit->nr_bos; i++) {
-               struct drm_gem_object *obj = submit->bos[i].obj;
-               submit_unlock_bo(submit, i);
-               if (error)
-                       drm_gem_object_put(obj);
+               /* job wasn't enqueued to scheduler, so early retirement: */
+               msm_submit_retire(submit);
        }
+
+       if (submit->exec.objects)
+               drm_exec_fini(&submit->exec);
 }
 
 void msm_submit_retire(struct msm_gem_submit *submit)
@@ -733,7 +659,6 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
        struct msm_submit_post_dep *post_deps = NULL;
        struct drm_syncobj **syncobjs_to_reset = NULL;
        int out_fence_fd = -1;
-       bool has_ww_ticket = false;
        unsigned i;
        int ret;
 
@@ -839,15 +764,15 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void 
*data,
                goto out;
 
        /* copy_*_user while holding a ww ticket upsets lockdep */
-       ww_acquire_init(&submit->ticket, &reservation_ww_class);
-       has_ww_ticket = true;
        ret = submit_lock_objects(submit);
        if (ret)
                goto out;
 
-       ret = submit_fence_sync(submit, !!(args->flags & 
MSM_SUBMIT_NO_IMPLICIT));
-       if (ret)
-               goto out;
+       if (!(args->flags & MSM_SUBMIT_NO_IMPLICIT)) {
+               ret = submit_fence_sync(submit);
+               if (ret)
+                       goto out;
+       }
 
        ret = submit_pin_objects(submit);
        if (ret)
@@ -978,8 +903,6 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 
 out:
        submit_cleanup(submit, !!ret);
-       if (has_ww_ticket)
-               ww_acquire_fini(&submit->ticket);
 out_unlock:
        mutex_unlock(&queue->lock);
 out_post_unlock:
-- 
2.42.0

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