2023-06-26 09:30:34

by Thomas Hellström

Subject: [PATCH v2 2/4] drm/ttm: Don't shadow the operation context

ttm_bo_swapout() shadows the ttm operation context which may cause
major confusion in driver callbacks when swapping out !TTM_PL_SYSTEM
memory. Fix this by reusing the operation context argument to
ttm_bo_swapout().

Cc: "Christian König" <[email protected]>
Cc: Roger He <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]> # v4.16+
Fixes: dc947770cf34 ("drm/ttm: enable swapout for reserved BOs during allocation")
Signed-off-by: Thomas Hellström <[email protected]>
Acked-by: Matthew Brost <[email protected]>
---
drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index bd5dae4d1624..615d30c4262d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1154,7 +1154,6 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
* Move to system cached
*/
if (bo->resource->mem_type != TTM_PL_SYSTEM) {
- struct ttm_operation_ctx ctx = { false, false };
struct ttm_resource *evict_mem;
struct ttm_place hop;

@@ -1164,7 +1163,7 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
if (unlikely(ret))
goto out;

- ret = ttm_bo_handle_move_mem(bo, evict_mem, true, &ctx, &hop);
+ ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
if (unlikely(ret != 0)) {
WARN(ret == -EMULTIHOP, "Unexpected multihop in swaput - likely driver bug.\n");
goto out;
--
2.40.1

2023-06-26 15:44:46

by Christian König

Subject: Re: [PATCH v2 2/4] drm/ttm: Don't shadow the operation context

Am 26.06.23 um 11:14 schrieb Thomas Hellström:
> ttm_bo_swapout() shadows the ttm operation context which may cause
> major confusion in driver callbacks when swapping out !TTM_PL_SYSTEM
> memory. Fix this by reusing the operation context argument to
> ttm_bo_swapout().
>
> Cc: "Christian König" <[email protected]>
> Cc: Roger He <[email protected]>
> Cc: <[email protected]>
> Cc: <[email protected]>
> Cc: <[email protected]> # v4.16+
> Fixes: dc947770cf34 ("drm/ttm: enable swapout for reserved BOs during allocation")
> Signed-off-by: Thomas Hellström <[email protected]>
> Acked-by: Matthew Brost <[email protected]>

We intentionally didn't used the parameter here, but I absolutely can't
figure out why.

Feel free to add my rb, but let's give it some time upstream before you
base anything on top of this. Just in case we missed something.

Regards,
Christian.

> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index bd5dae4d1624..615d30c4262d 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -1154,7 +1154,6 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
> * Move to system cached
> */
> if (bo->resource->mem_type != TTM_PL_SYSTEM) {
> - struct ttm_operation_ctx ctx = { false, false };
> struct ttm_resource *evict_mem;
> struct ttm_place hop;
>
> @@ -1164,7 +1163,7 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
> if (unlikely(ret))
> goto out;
>
> - ret = ttm_bo_handle_move_mem(bo, evict_mem, true, &ctx, &hop);
> + ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
> if (unlikely(ret != 0)) {
> WARN(ret == -EMULTIHOP, "Unexpected multihop in swaput - likely driver bug.\n");
> goto out;

2023-06-26 15:45:26

by Thomas Hellström

Subject: Re: [PATCH v2 2/4] drm/ttm: Don't shadow the operation context

On Mon, 2023-06-26 at 17:15 +0200, Christian König wrote:
> Am 26.06.23 um 11:14 schrieb Thomas Hellström:
> > ttm_bo_swapout() shadows the ttm operation context which may cause
> > major confusion in driver callbacks when swapping out
> > !TTM_PL_SYSTEM
> > memory. Fix this by reusing the operation context argument to
> > ttm_bo_swapout().
> >
> > Cc: "Christian König" <[email protected]>
> > Cc: Roger He <[email protected]>
> > Cc: <[email protected]>
> > Cc: <[email protected]>
> > Cc: <[email protected]> # v4.16+
> > Fixes: dc947770cf34 ("drm/ttm: enable swapout for reserved BOs
> > during allocation")
> > Signed-off-by: Thomas Hellström <[email protected]>
> > Acked-by: Matthew Brost <[email protected]>
>
> We intentionally didn't used the parameter here, but I absolutely
> can't
> figure out why.
>
> Feel free to add my rb, but let's give it some time upstream before
> you
> base anything on top of this. Just in case we missed something.

Sure. Thanks for reviewing,
/Thomas

>
> Regards,
> Christian.
>
> > ---
> >   drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> > b/drivers/gpu/drm/ttm/ttm_bo.c
> > index bd5dae4d1624..615d30c4262d 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > @@ -1154,7 +1154,6 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > *bo, struct ttm_operation_ctx *ctx,
> >          * Move to system cached
> >          */
> >         if (bo->resource->mem_type != TTM_PL_SYSTEM) {
> > -               struct ttm_operation_ctx ctx = { false, false };
> >                 struct ttm_resource *evict_mem;
> >                 struct ttm_place hop;
> >  
> > @@ -1164,7 +1163,7 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > *bo, struct ttm_operation_ctx *ctx,
> >                 if (unlikely(ret))
> >                         goto out;
> >  
> > -               ret = ttm_bo_handle_move_mem(bo, evict_mem, true,
> > &ctx, &hop);
> > +               ret = ttm_bo_handle_move_mem(bo, evict_mem, true,
> > ctx, &hop);
> >                 if (unlikely(ret != 0)) {
> >                         WARN(ret == -EMULTIHOP, "Unexpected
> > multihop in swaput - likely driver bug.\n");
> >                         goto out;
>

2023-06-26 16:06:40

by Thomas Hellström

Subject: Re: [Intel-xe] [PATCH v2 2/4] drm/ttm: Don't shadow the operation context

On Mon, 2023-06-26 at 17:18 +0200, Thomas Hellström wrote:
> On Mon, 2023-06-26 at 17:15 +0200, Christian König wrote:
> > Am 26.06.23 um 11:14 schrieb Thomas Hellström:
> > > ttm_bo_swapout() shadows the ttm operation context which may
> > > cause
> > > major confusion in driver callbacks when swapping out
> > > !TTM_PL_SYSTEM
> > > memory. Fix this by reusing the operation context argument to
> > > ttm_bo_swapout().
> > >
> > > Cc: "Christian König" <[email protected]>
> > > Cc: Roger He <[email protected]>
> > > Cc: <[email protected]>
> > > Cc: <[email protected]>
> > > Cc: <[email protected]> # v4.16+
> > > Fixes: dc947770cf34 ("drm/ttm: enable swapout for reserved BOs
> > > during allocation")
> > > Signed-off-by: Thomas Hellström
> > > <[email protected]>
> > > Acked-by: Matthew Brost <[email protected]>
> >
> > We intentionally didn't used the parameter here, but I absolutely
> > can't
> > figure out why.
> >
> > Feel free to add my rb, but let's give it some time upstream before
> > you
> > base anything on top of this. Just in case we missed something.
>
> Sure. Thanks for reviewing,

BTW, I'll remove the Fixes: tag as well.

/Thomas


> /Thomas
>
> >
> > Regards,
> > Christian.
> >
> > > ---
> > >   drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
> > >   1 file changed, 1 insertion(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> > > b/drivers/gpu/drm/ttm/ttm_bo.c
> > > index bd5dae4d1624..615d30c4262d 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > @@ -1154,7 +1154,6 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > > *bo, struct ttm_operation_ctx *ctx,
> > >          * Move to system cached
> > >          */
> > >         if (bo->resource->mem_type != TTM_PL_SYSTEM) {
> > > -               struct ttm_operation_ctx ctx = { false, false };
> > >                 struct ttm_resource *evict_mem;
> > >                 struct ttm_place hop;
> > >  
> > > @@ -1164,7 +1163,7 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > > *bo, struct ttm_operation_ctx *ctx,
> > >                 if (unlikely(ret))
> > >                         goto out;
> > >  
> > > -               ret = ttm_bo_handle_move_mem(bo, evict_mem, true,
> > > &ctx, &hop);
> > > +               ret = ttm_bo_handle_move_mem(bo, evict_mem, true,
> > > ctx, &hop);
> > >                 if (unlikely(ret != 0)) {
> > >                         WARN(ret == -EMULTIHOP, "Unexpected
> > > multihop in swaput - likely driver bug.\n");
> > >                         goto out;
> >
>