On Tue, Jul 21, 2020 at 09:32:36AM +0200, Christian König wrote:
Nouveau is the only user of this functionality and evicting io space on -EAGAIN is really a misuse of the return code.
Instead switch to using -ENOSPC here which makes much more sense and simplifies the code.
Signed-off-by: Christian König christian.koenig@amd.com
Going from EAGAIN to something else could unbreak something that's held together as a almost livelock restarting ioctls or whatever. So I looked for that a bit:
- mmap path seems fine, all errors from the io_reserve stuff here get remapped to sigbus
- but everywhere else we just pass down the errno it seems, and nouveau has a bunch of kmaps all around (gpu relocs on pre-nv50 is probably the big one, if we ignore the memcpy bo move fallback). I haven't found anything that indicates those chips don't have the ioremapping hw, so there's some risk I think. Otoh I also don't see anything that would unbreak the lifelook, so feels minimally.
With that impact to pushbuf ioctl documented in the commit message somehow this is Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
drivers/gpu/drm/nouveau/nouveau_bo.c | 2 -- drivers/gpu/drm/ttm/ttm_bo_util.c | 4 ++-- 2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c index 61355cfb7335..a48652826f67 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bo.c +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c @@ -1505,8 +1505,6 @@ nouveau_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_reg *reg) if (ret != 1) { if (WARN_ON(ret == 0)) return -EINVAL;
if (ret == -ENOSPC)return -EAGAIN; return ret; }diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 5e0f3a9caedc..7d2c50fef456 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -116,7 +116,7 @@ static int ttm_mem_io_evict(struct ttm_mem_type_manager *man) struct ttm_buffer_object *bo;
if (!man->use_io_reserve_lru || list_empty(&man->io_reserve_lru))
return -EAGAIN;
return -ENOSPC;bo = list_first_entry(&man->io_reserve_lru, struct ttm_buffer_object,
@@ -143,7 +143,7 @@ int ttm_mem_io_reserve(struct ttm_bo_device *bdev, mem->bus.io_reserved_count++ == 0) { retry: ret = bdev->driver->io_mem_reserve(bdev, mem);
if (ret == -EAGAIN) {
if (ret == -ENOSPC) { ret = ttm_mem_io_evict(man); if (ret == 0) goto retry;-- 2.17.1
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel