[RFC PATCH v3 13/21] drm/exec: Rework contended locking
Thomas Hellström
thomas.hellstrom at linux.intel.com
Wed May 22 14:32:55 UTC 2024
On Wed, 2024-05-22 at 07:52 +0200, Christian König wrote:
> Am 21.05.24 um 09:16 schrieb Thomas Hellström:
> > If contention and backoff occurs during a drm_exec ww transaction,
> > the contended lock is not locked again until the next orinary
> > attempt to lock a dma_resv lock. However, with the introduction of
> > drm_exec_trylock(), that doesn't work, since the locking of the
> > contended lock needs to be a sleeping lock. Neither can we ignore
> > locking the contended lock during a trylock since that would
> > violate
> > at least the ww_mutex annotations.
> >
> > So resolve this by actually locking the contended lock during
> > drm_exec_retry_on_contention(). However, this introduces a new
> > point
> > of failure since locking the contended lock may return -EINTR.
> >
> > Hence drm_exec_retry_on_contention() must take an error parameter
> > and
> > also return a value indicating success.
>
> After thinking more about that I have to pretty clearly NAK this.
>
I thought we were beyond upfront NAKing in the first reply :/
> It's an intentional design decision to guarantee that at the start of
> the loop no object is locked.
>
> This is because Sima and I wanted to integrate userptr handling into
> drm_exec as well in the long term.
First I agree the interface looks worse with this patch.
But I thought generic userptr handling were going to end up as a gpuvm
helper (without using GEM objects) as we've discussed previously.
Anyway if still there would be helpers in drm_exec for some other
generic userptr solution, those need to be done before the
ww_acquire_ctx_init(). The contended locking here is done after, so I
can't really see how these would clash.
Still, If we need to come up with another solution, I think it's fair
we clearly sort out why.
> I think we should just document that drm_exec_trylock() can't be used
> to
> lock the first BO in the loop and explicitly WARN if that's the case.
Unfortunately that's not sufficient for the general use-case. If we
want to keep the ttm_bo_vm approach of dropping the mmap lock when
there is contention on the bo resv, we need to be able to trylock on
first lock. Also bo creation is using trylock but might be able to use
a sleeping lock there. But if that sleeping lock triggers an -EDEADLK
(DEBUG_WW_MUTEX_SLOWPATH) we have the weird situation of referencing an
object that never was fully created as a contending object.
So the only really working alternative solution I can see is that
drm_exec_trylock simply fails if there is a contended lock and we'd
need to live with the weird bo creation situation described above.
/Thomas
>
> Regards,
> Christian.
>
> >
> > Cc: Christian König <christian.koenig at amd.com>
> > Cc: Somalapuram Amaranath <Amaranath.Somalapuram at amd.com>
> > Cc: Matthew Brost <matthew.brost at intel.com>
> > Cc: <dri-devel at lists.freedesktop.org>
> > Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> > ---
> > .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 ++++-----
> > drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 ++--
> > drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c | 4 +--
> > drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 8 ++---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c | 8 ++---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c | 4 +--
> > drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c | 8 ++---
> > drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 +-
> > drivers/gpu/drm/drm_exec.c | 35
> > ++++++++++++++-----
> > drivers/gpu/drm/drm_gpuvm.c | 8 ++---
> > drivers/gpu/drm/imagination/pvr_job.c | 2 +-
> > drivers/gpu/drm/msm/msm_gem_submit.c | 2 +-
> > drivers/gpu/drm/nouveau/nouveau_uvmm.c | 2 +-
> > drivers/gpu/drm/tests/drm_exec_test.c | 12 +++----
> > drivers/gpu/drm/xe/xe_gt_pagefault.c | 4 +--
> > drivers/gpu/drm/xe/xe_vm.c | 10 +++---
> > include/drm/drm_exec.h | 23 +++++++++---
> > 17 files changed, 92 insertions(+), 62 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > index e4d4e55c08ad..4a08a692aa1f 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > @@ -1152,12 +1152,12 @@ static int reserve_bo_and_vm(struct kgd_mem
> > *mem,
> > drm_exec_init(&ctx->exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> > drm_exec_until_all_locked(&ctx->exec) {
> > ret = amdgpu_vm_lock_pd(vm, &ctx->exec, 2);
> > - drm_exec_retry_on_contention(&ctx->exec);
> > + ret = drm_exec_retry_on_contention(&ctx->exec,
> > ret);
> > if (unlikely(ret))
> > goto error;
> >
> > ret = drm_exec_prepare_obj(&ctx->exec, &bo-
> > >tbo.base, 1);
> > - drm_exec_retry_on_contention(&ctx->exec);
> > + ret = drm_exec_retry_on_contention(&ctx->exec,
> > ret);
> > if (unlikely(ret))
> > goto error;
> > }
> > @@ -1199,14 +1199,14 @@ static int reserve_bo_and_cond_vms(struct
> > kgd_mem *mem,
> >
> > ret = amdgpu_vm_lock_pd(entry->bo_va-
> > >base.vm,
> > &ctx->exec, 2);
> > - drm_exec_retry_on_contention(&ctx->exec);
> > + ret = drm_exec_retry_on_contention(&ctx-
> > >exec, ret);
> > if (unlikely(ret))
> > goto error;
> > ++ctx->n_vms;
> > }
> >
> > ret = drm_exec_prepare_obj(&ctx->exec, &bo-
> > >tbo.base, 1);
> > - drm_exec_retry_on_contention(&ctx->exec);
> > + ret = drm_exec_retry_on_contention(&ctx->exec,
> > ret);
> > if (unlikely(ret))
> > goto error;
> > }
> > @@ -2619,7 +2619,7 @@ static int validate_invalid_user_pages(struct
> > amdkfd_process_info *process_info)
> > list_for_each_entry(peer_vm, &process_info-
> > >vm_list_head,
> > vm_list_node) {
> > ret = amdgpu_vm_lock_pd(peer_vm, &exec,
> > 2);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec,
> > ret);
> > if (unlikely(ret))
> > goto unreserve_out;
> > }
> > @@ -2631,7 +2631,7 @@ static int validate_invalid_user_pages(struct
> > amdkfd_process_info *process_info)
> >
> > gobj = &mem->bo->tbo.base;
> > ret = drm_exec_prepare_obj(&exec, gobj,
> > 1);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec,
> > ret);
> > if (unlikely(ret))
> > goto unreserve_out;
> > }
> > @@ -2875,7 +2875,7 @@ int
> > amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct
> > dma_fence __rcu *
> > list_for_each_entry(peer_vm, &process_info-
> > >vm_list_head,
> > vm_list_node) {
> > ret = amdgpu_vm_lock_pd(peer_vm, &exec,
> > 2);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec,
> > ret);
> > if (unlikely(ret)) {
> > pr_err("Locking VM PD failed, ret:
> > %d\n", ret);
> > goto ttm_reserve_fail;
> > @@ -2891,7 +2891,7 @@ int
> > amdgpu_amdkfd_gpuvm_restore_process_bos(void *info, struct
> > dma_fence __rcu *
> >
> > gobj = &mem->bo->tbo.base;
> > ret = drm_exec_prepare_obj(&exec, gobj,
> > 1);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec,
> > ret);
> > if (unlikely(ret)) {
> > pr_err("drm_exec_prepare_obj
> > failed, ret: %d\n", ret);
> > goto ttm_reserve_fail;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > index ec888fc6ead8..299e46a6d934 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > @@ -897,7 +897,7 @@ static int amdgpu_cs_parser_bos(struct
> > amdgpu_cs_parser *p,
> >
> > drm_exec_until_all_locked(&p->exec) {
> > r = amdgpu_vm_lock_pd(&fpriv->vm, &p->exec, 1 + p-
> > >gang_size);
> > - drm_exec_retry_on_contention(&p->exec);
> > + r = drm_exec_retry_on_contention(&p->exec, r);
> > if (unlikely(r))
> > goto out_free_user_pages;
> >
> > @@ -905,7 +905,7 @@ static int amdgpu_cs_parser_bos(struct
> > amdgpu_cs_parser *p,
> > /* One fence for TTM and one for each CS
> > job */
> > r = drm_exec_prepare_obj(&p->exec, &e->bo-
> > >tbo.base,
> > 1 + p-
> > >gang_size);
> > - drm_exec_retry_on_contention(&p->exec);
> > + r = drm_exec_retry_on_contention(&p->exec,
> > r);
> > if (unlikely(r))
> > goto out_free_user_pages;
> >
> > @@ -915,7 +915,7 @@ static int amdgpu_cs_parser_bos(struct
> > amdgpu_cs_parser *p,
> > if (p->uf_bo) {
> > r = drm_exec_prepare_obj(&p->exec, &p-
> > >uf_bo->tbo.base,
> > 1 + p-
> > >gang_size);
> > - drm_exec_retry_on_contention(&p->exec);
> > + r = drm_exec_retry_on_contention(&p->exec,
> > r);
> > if (unlikely(r))
> > goto out_free_user_pages;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> > index cfdf558b48b6..8b2b86c7a6c5 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> > @@ -74,7 +74,7 @@ int amdgpu_map_static_csa(struct amdgpu_device
> > *adev, struct amdgpu_vm *vm,
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > if (likely(!r))
> > r = drm_exec_lock_obj(&exec, &bo-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r)) {
> > DRM_ERROR("failed to reserve CSA,PD BOs:
> > err=%d\n", r);
> > goto error;
> > @@ -114,7 +114,7 @@ int amdgpu_unmap_static_csa(struct
> > amdgpu_device *adev, struct amdgpu_vm *vm,
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > if (likely(!r))
> > r = drm_exec_lock_obj(&exec, &bo-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r)) {
> > DRM_ERROR("failed to reserve CSA,PD BOs:
> > err=%d\n", r);
> > goto error;
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > index 67c234bcf89f..17e16c971e21 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > @@ -239,12 +239,12 @@ static void amdgpu_gem_object_close(struct
> > drm_gem_object *obj,
> > drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
> > drm_exec_until_all_locked(&exec) {
> > r = drm_exec_prepare_obj(&exec, &bo->tbo.base, 1);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> >
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> > }
> > @@ -776,13 +776,13 @@ int amdgpu_gem_va_ioctl(struct drm_device
> > *dev, void *data,
> > drm_exec_until_all_locked(&exec) {
> > if (gobj) {
> > r = drm_exec_lock_obj(&exec, gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec,
> > r);
> > if (unlikely(r))
> > goto error;
> > }
> >
> > r = amdgpu_vm_lock_pd(&fpriv->vm, &exec, 2);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> > index 5ca5c47ab54e..1b1a5147606e 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
> > @@ -1221,12 +1221,12 @@ int amdgpu_mes_ctx_map_meta_data(struct
> > amdgpu_device *adev,
> > drm_exec_until_all_locked(&exec) {
> > r = drm_exec_lock_obj(&exec,
> > &ctx_data->meta_data_obj-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error_fini_exec;
> >
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error_fini_exec;
> > }
> > @@ -1292,12 +1292,12 @@ int amdgpu_mes_ctx_unmap_meta_data(struct
> > amdgpu_device *adev,
> > drm_exec_until_all_locked(&exec) {
> > r = drm_exec_lock_obj(&exec,
> > &ctx_data->meta_data_obj-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> >
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c
> > index e22cb2b5cd92..72b8213e352c 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_seq64.c
> > @@ -77,7 +77,7 @@ int amdgpu_seq64_map(struct amdgpu_device *adev,
> > struct amdgpu_vm *vm,
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > if (likely(!r))
> > r = drm_exec_lock_obj(&exec, &bo-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error;
> > }
> > @@ -138,7 +138,7 @@ void amdgpu_seq64_unmap(struct amdgpu_device
> > *adev, struct amdgpu_fpriv *fpriv)
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > if (likely(!r))
> > r = drm_exec_lock_obj(&exec, &bo-
> > >tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c
> > index e01c1c8e64c4..63392ce43945 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_umsch_mm.c
> > @@ -89,12 +89,12 @@ static int map_ring_data(struct amdgpu_device
> > *adev, struct amdgpu_vm *vm,
> > drm_exec_init(&exec, 0, 0);
> > drm_exec_until_all_locked(&exec) {
> > r = drm_exec_lock_obj(&exec, &bo->tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error_fini_exec;
> >
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto error_fini_exec;
> > }
> > @@ -152,12 +152,12 @@ static int unmap_ring_data(struct
> > amdgpu_device *adev, struct amdgpu_vm *vm,
> > drm_exec_init(&exec, 0, 0);
> > drm_exec_until_all_locked(&exec) {
> > r = drm_exec_lock_obj(&exec, &bo->tbo.base);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> >
> > r = amdgpu_vm_lock_pd(vm, &exec, 0);
> > - drm_exec_retry_on_contention(&exec);
> > + r = drm_exec_retry_on_contention(&exec, r);
> > if (unlikely(r))
> > goto out_unlock;
> > }
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > index 386875e6eb96..a3aa7fd22f6a 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > @@ -1499,7 +1499,7 @@ static int svm_range_reserve_bos(struct
> > svm_validate_context *ctx, bool intr)
> > vm = drm_priv_to_vm(pdd->drm_priv);
> >
> > r = amdgpu_vm_lock_pd(vm, &ctx->exec, 2);
> > - drm_exec_retry_on_contention(&ctx->exec);
> > + r = drm_exec_retry_on_contention(&ctx-
> > >exec, r);
> > if (unlikely(r)) {
> > pr_debug("failed %d to reserve
> > bo\n", r);
> > goto unreserve_out;
> > diff --git a/drivers/gpu/drm/drm_exec.c
> > b/drivers/gpu/drm/drm_exec.c
> > index 2da094bdf8a4..3770a5d30213 100644
> > --- a/drivers/gpu/drm/drm_exec.c
> > +++ b/drivers/gpu/drm/drm_exec.c
> > @@ -28,12 +28,12 @@
> > * drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
> > * drm_exec_until_all_locked(&exec) {
> > * ret = drm_exec_prepare_obj(&exec, boA, 1);
> > - * drm_exec_retry_on_contention(&exec);
> > + * ret = drm_exec_retry_on_contention(&exec, ret);
> > * if (ret)
> > * goto error;
> > *
> > * ret = drm_exec_prepare_obj(&exec, boB, 1);
> > - * drm_exec_retry_on_contention(&exec);
> > + * ret = drm_exec_retry_on_contention(&exec, ret);
> > * if (ret)
> > * goto error;
> > * }
> > @@ -48,7 +48,8 @@
> > */
> >
> > /* Dummy value used to initially enter the retry loop */
> > -#define DRM_EXEC_DUMMY ((void *)~0)
> > +#define DRM_EXEC_DUMMY ERR_PTR(-ESTALE)
> > +#define DRM_EXEC_CONTENDED ERR_PTR(-EDEADLK)
> >
> > /* Unlock all objects and drop references */
> > static void drm_exec_unlock_all(struct drm_exec *exec)
> > @@ -131,8 +132,7 @@ bool drm_exec_cleanup(struct drm_exec *exec)
> > return true;
> > }
> >
> > - drm_exec_unlock_all(exec);
> > - exec->num_objects = 0;
> > + exec->contended = NULL;
> > return true;
> > }
> > EXPORT_SYMBOL(drm_exec_cleanup);
> > @@ -194,6 +194,27 @@ static int drm_exec_lock_contended(struct
> > drm_exec *exec)
> > return ret;
> > }
> >
> > +/**
> > + * drm_exec_handle_contended() - Perform cleanup before a ww
> > transaction restart
> > + * @exec: Pointer to the drm_exec object.
> > + *
> > + * Unlocks all held resvs and re-locks the contended object.
> > + *
> > + * Return: 0 on success, negative error code on failure.
> > + */
> > +int drm_exec_handle_contended(struct drm_exec *exec)
> > +{
> > + int ret;
> > +
> > + drm_exec_unlock_all(exec);
> > + exec->num_objects = 0;
> > + ret = drm_exec_lock_contended(exec);
> > + exec->contended = DRM_EXEC_CONTENDED;
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(drm_exec_handle_contended);
> > +
> > /**
> > * drm_exec_lock_obj - lock a GEM object for use
> > * @exec: the drm_exec object with the state
> > @@ -209,10 +230,6 @@ int drm_exec_lock_obj(struct drm_exec *exec,
> > struct drm_gem_object *obj)
> > {
> > int ret;
> >
> > - ret = drm_exec_lock_contended(exec);
> > - if (unlikely(ret))
> > - return ret;
> > -
> > if (exec->prelocked == obj) {
> > drm_gem_object_put(exec->prelocked);
> > exec->prelocked = NULL;
> > diff --git a/drivers/gpu/drm/drm_gpuvm.c
> > b/drivers/gpu/drm/drm_gpuvm.c
> > index f9eb56f24bef..0923d6ae18e2 100644
> > --- a/drivers/gpu/drm/drm_gpuvm.c
> > +++ b/drivers/gpu/drm/drm_gpuvm.c
> > @@ -1254,18 +1254,18 @@ drm_gpuvm_exec_lock(struct drm_gpuvm_exec
> > *vm_exec)
> >
> > drm_exec_until_all_locked(exec) {
> > ret = drm_gpuvm_prepare_vm(gpuvm, exec,
> > num_fences);
> > - drm_exec_retry_on_contention(exec);
> > + ret = drm_exec_retry_on_contention(exec, ret);
> > if (ret)
> > goto err;
> >
> > ret = drm_gpuvm_prepare_objects(gpuvm, exec,
> > num_fences);
> > - drm_exec_retry_on_contention(exec);
> > + ret = drm_exec_retry_on_contention(exec, ret);
> > if (ret)
> > goto err;
> >
> > if (vm_exec->extra.fn) {
> > ret = vm_exec->extra.fn(vm_exec);
> > - drm_exec_retry_on_contention(exec);
> > + ret = drm_exec_retry_on_contention(exec,
> > ret);
> > if (ret)
> > goto err;
> > }
> > @@ -1346,7 +1346,7 @@ drm_gpuvm_exec_lock_range(struct
> > drm_gpuvm_exec *vm_exec,
> > drm_exec_until_all_locked(exec) {
> > ret = drm_gpuvm_prepare_range(gpuvm, exec, addr,
> > range,
> > vm_exec-
> > >num_fences);
> > - drm_exec_retry_on_contention(exec);
> > + ret = drm_exec_retry_on_contention(exec, ret);
> > if (ret)
> > goto err;
> > }
> > diff --git a/drivers/gpu/drm/imagination/pvr_job.c
> > b/drivers/gpu/drm/imagination/pvr_job.c
> > index 78c2f3c6dce0..6e0ce6c4576c 100644
> > --- a/drivers/gpu/drm/imagination/pvr_job.c
> > +++ b/drivers/gpu/drm/imagination/pvr_job.c
> > @@ -574,7 +574,7 @@ prepare_job_resvs_for_each(struct drm_exec
> > *exec, struct pvr_job_data *job_data,
> > drm_exec_until_all_locked(exec) {
> > int err = jobs_lock_all_objs(exec, job_data,
> > job_count);
> >
> > - drm_exec_retry_on_contention(exec);
> > + err = drm_exec_retry_on_contention(exec, err);
> > if (err)
> > return err;
> > }
> > diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c
> > b/drivers/gpu/drm/msm/msm_gem_submit.c
> > index fba78193127d..01992b43ea4b 100644
> > --- a/drivers/gpu/drm/msm/msm_gem_submit.c
> > +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
> > @@ -259,7 +259,7 @@ static int submit_lock_objects(struct
> > msm_gem_submit *submit)
> > 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);
> > + ret =
> > drm_exec_retry_on_contention(&submit->exec, ret);
> > if (ret)
> > goto error;
> > }
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> > b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> > index ee02cd833c5e..0c871634fdfb 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
> > @@ -1350,7 +1350,7 @@ nouveau_uvmm_bind_job_submit(struct
> > nouveau_job *job,
> > drm_exec_init(exec, vme->flags, 0);
> > drm_exec_until_all_locked(exec) {
> > ret = bind_lock_validate(job, exec, vme-
> > >num_fences);
> > - drm_exec_retry_on_contention(exec);
> > + ret = drm_exec_retry_on_contention(exec, ret);
> > if (ret) {
> > op = list_last_op(&bind_job->ops);
> > goto unwind;
> > diff --git a/drivers/gpu/drm/tests/drm_exec_test.c
> > b/drivers/gpu/drm/tests/drm_exec_test.c
> > index 81f928a429ba..28558fdb08df 100644
> > --- a/drivers/gpu/drm/tests/drm_exec_test.c
> > +++ b/drivers/gpu/drm/tests/drm_exec_test.c
> > @@ -63,7 +63,7 @@ static void test_lock(struct kunit *test)
> > drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = drm_exec_lock_obj(&exec, &gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> > @@ -83,14 +83,14 @@ static void test_lock_unlock(struct kunit
> > *test)
> > drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = drm_exec_lock_obj(&exec, &gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> >
> > drm_exec_unlock_obj(&exec, &gobj);
> > ret = drm_exec_lock_obj(&exec, &gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> > @@ -110,13 +110,13 @@ static void test_duplicates(struct kunit
> > *test)
> > drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = drm_exec_lock_obj(&exec, &gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> >
> > ret = drm_exec_lock_obj(&exec, &gobj);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> > @@ -137,7 +137,7 @@ static void test_prepare(struct kunit *test)
> > drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = drm_exec_prepare_obj(&exec, &gobj, 1);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > KUNIT_EXPECT_EQ(test, ret, 0);
> > if (ret)
> > break;
> > diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c
> > b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> > index 040dd142c49c..20ec1ab1b52d 100644
> > --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
> > +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> > @@ -200,7 +200,7 @@ static int handle_pagefault(struct xe_gt *gt,
> > struct pagefault *pf)
> > drm_exec_init(&exec, 0, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = xe_pf_begin(&exec, vma, atomic, tile->id);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > if (ret)
> > goto unlock_dma_resv;
> >
> > @@ -543,7 +543,7 @@ static int handle_acc(struct xe_gt *gt, struct
> > acc *acc)
> > drm_exec_init(&exec, 0, 0);
> > drm_exec_until_all_locked(&exec) {
> > ret = xe_pf_begin(&exec, vma, true, tile->id);
> > - drm_exec_retry_on_contention(&exec);
> > + ret = drm_exec_retry_on_contention(&exec, ret);
> > if (ret)
> > break;
> > }
> > diff --git a/drivers/gpu/drm/xe/xe_vm.c
> > b/drivers/gpu/drm/xe/xe_vm.c
> > index e2ec148c9c33..335524e803e7 100644
> > --- a/drivers/gpu/drm/xe/xe_vm.c
> > +++ b/drivers/gpu/drm/xe/xe_vm.c
> > @@ -501,7 +501,7 @@ static void preempt_rebind_work_func(struct
> > work_struct *w)
> > bool done = false;
> >
> > err = xe_preempt_work_begin(&exec, vm, &done);
> > - drm_exec_retry_on_contention(&exec);
> > + err = drm_exec_retry_on_contention(&exec, err);
> > if (err || done) {
> > drm_exec_fini(&exec);
> > if (err &&
> > xe_vm_validate_should_retry(&exec, err, &end))
> > @@ -1052,7 +1052,7 @@ static void xe_vma_destroy_unlocked(struct
> > xe_vma *vma)
> > drm_exec_init(&exec, 0, 0);
> > drm_exec_until_all_locked(&exec) {
> > err = xe_vm_lock_vma(&exec, vma);
> > - drm_exec_retry_on_contention(&exec);
> > + err = drm_exec_retry_on_contention(&exec, err);
> > if (XE_WARN_ON(err))
> > break;
> > }
> > @@ -2148,11 +2148,11 @@ static struct xe_vma *new_vma(struct xe_vm
> > *vm, struct drm_gpuva_op_map *op,
> > err = 0;
> > if (!bo->vm) {
> > err = drm_exec_lock_obj(&exec,
> > xe_vm_obj(vm));
> > -
> > drm_exec_retry_on_contention(&exec);
> > + err =
> > drm_exec_retry_on_contention(&exec, err);
> > }
> > if (!err) {
> > err = drm_exec_lock_obj(&exec,
> > &bo->ttm.base);
> > -
> > drm_exec_retry_on_contention(&exec);
> > + err =
> > drm_exec_retry_on_contention(&exec, err);
> > }
> > if (err) {
> > drm_exec_fini(&exec);
> > @@ -2884,7 +2884,7 @@ static int vm_bind_ioctl_ops_execute(struct
> > xe_vm *vm,
> > DRM_EXEC_IGNORE_DUPLICATES, 0);
> > drm_exec_until_all_locked(&exec) {
> > err = vm_bind_ioctl_ops_lock_and_prep(&exec, vm,
> > vops);
> > - drm_exec_retry_on_contention(&exec);
> > + err = drm_exec_retry_on_contention(&exec, err);
> > if (err)
> > goto unlock;
> >
> > diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h
> > index aa786b828a0a..fafb40d96e38 100644
> > --- a/include/drm/drm_exec.h
> > +++ b/include/drm/drm_exec.h
> > @@ -51,6 +51,8 @@ struct drm_exec {
> > struct drm_gem_object *prelocked;
> > };
> >
> > +int drm_exec_handle_contended(struct drm_exec *exec);
> > +
> > /**
> > * drm_exec_obj() - Return the object for a give drm_exec index
> > * @exec: Pointer to the drm_exec context
> > @@ -113,15 +115,26 @@ __PASTE(__drm_exec_,
> > __LINE__): \
> > /**
> > * drm_exec_retry_on_contention - restart the loop to grap all
> > locks
> > * @exec: drm_exec object
> > + * @_ret: The current error status
> > *
> > * Control flow helper to continue when a contention was detected
> > and we need to
> > * clean up and re-start the loop to prepare all GEM objects.
> > + *
> > + * Return: If no loop restart occurred: The error status.
> > */
> > -#define drm_exec_retry_on_contention(exec) \
> > - do { \
> > - if (unlikely(drm_exec_is_contended(exec))) \
> > - goto *__drm_exec_retry_ptr; \
> > - } while (0)
> > +#define drm_exec_retry_on_contention(exec,
> > _ret) \
> > + ({
> > \
> > + struct drm_exec *__exec =
> > (exec); \
> > + int __ret =
> > (_ret); \
> > +
> > \
> > + if (unlikely(drm_exec_is_contended(__exec)))
> > { \
> > + WARN_ON(__ret != -
> > EDEADLK); \
> > + __ret =
> > drm_exec_handle_contended(__exec); \
> > + if
> > (!__ret) \
> > + goto
> > *__drm_exec_retry_ptr; \
> > + }
> > \
> > + __ret;
> > \
> > + })
> >
> > /**
> > * drm_exec_is_contended - check for contention
>
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