On 8/16/21 3:25 PM, Matthew Auld wrote:
On Mon, 16 Aug 2021 at 09:49, Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> wrote:It's only used by the for_i915_gem_ww() macro and we can use the (typically) on-stack _err variable in its place. While initially setting the _err variable to -EDEADLK to enter the loop, we clear it before actually entering using fetch_and_zero() to avoid empty loops or code not setting the _err variable running forever. Suggested-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_gem_ww.h | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_ww.h b/drivers/gpu/drm/i915/i915_gem_ww.h index f6b1a796667b..98348b1e6182 100644 --- a/drivers/gpu/drm/i915/i915_gem_ww.h +++ b/drivers/gpu/drm/i915/i915_gem_ww.h @@ -7,12 +7,13 @@ #include <drm/drm_drv.h> +#include "i915_utils.h" + struct i915_gem_ww_ctx { struct ww_acquire_ctx ctx; struct list_head obj_list; struct drm_i915_gem_object *contended; - unsigned short intr; - unsigned short loop; + bool intr; }; void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr); @@ -23,28 +24,20 @@ void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj); /* Internal functions used by the inlines! Don't use. */ static inline int __i915_gem_ww_fini(struct i915_gem_ww_ctx *ww, int err) { - ww->loop = 0; if (err == -EDEADLK) { err = i915_gem_ww_ctx_backoff(ww); if (!err) - ww->loop = 1; + err = -EDEADLK; } - if (!ww->loop) + if (err != -EDEADLK) i915_gem_ww_ctx_fini(ww); return err; } -static inline void -__i915_gem_ww_init(struct i915_gem_ww_ctx *ww, bool intr) -{ - i915_gem_ww_ctx_init(ww, intr); - ww->loop = 1; -} - -#define for_i915_gem_ww(_ww, _err, _intr) \ - for (__i915_gem_ww_init(_ww, _intr); (_ww)->loop; \ +#define for_i915_gem_ww(_ww, _err, _intr) \ + for (i915_gem_ww_ctx_init(_ww, _intr), (_err) = -EDEADLK; \ + fetch_and_zero(&_err) == -EDEADLK; \Doesn't this now hide "normal" errors, like say get_pages() returning -ENOSPC or so?
Yes, good catch. We should either just clear the -EDEADLK case, or not clear the error at all..
/Thomas
