gpu: nvgpu: Correctly plumb -EAGAIN from vidmem allocations

Userspace can and should retry vidmem allocations if there are pending
clears still to be executed by the GPU. But this requires the -EAGAIN
to properly propagate back to userspace.

Bug 200378648

Change-Id: Ib930711270439843e043d65c2e87b60612a76239
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1669099
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/common/mm/vidmem.c b/drivers/gpu/nvgpu/common/mm/vidmem.c
index 4239bd06..e4137090 100644
--- a/drivers/gpu/nvgpu/common/mm/vidmem.c
+++ b/drivers/gpu/nvgpu/common/mm/vidmem.c
@@ -503,16 +503,18 @@ struct nvgpu_vidmem_buf *nvgpu_vidmem_user_alloc(struct gk20a *g, size_t bytes)
 
         err = nvgpu_vidmem_clear_all(g);
         if (err)
-                return NULL;
+                return ERR_PTR(-ENOMEM);
 
         buf = nvgpu_kzalloc(g, sizeof(*buf));
         if (!buf)
-                return NULL;
+                return ERR_PTR(-ENOMEM);
 
         buf->g = g;
         buf->mem = nvgpu_kzalloc(g, sizeof(*buf->mem));
-        if (!buf->mem)
+        if (!buf->mem) {
+                err = -ENOMEM;
                 goto fail;
+        }
 
         err = nvgpu_dma_alloc_vid(g, bytes, buf->mem);
         if (err)
@@ -530,7 +532,7 @@ fail:
         /* buf will never be NULL here. */
         nvgpu_kfree(g, buf->mem);
         nvgpu_kfree(g, buf);
-        return NULL;
+        return ERR_PTR(err);
 }
 
 void nvgpu_vidmem_buf_free(struct gk20a *g, struct nvgpu_vidmem_buf *buf)
@@ -538,7 +540,7 @@ void nvgpu_vidmem_buf_free(struct gk20a *g, struct nvgpu_vidmem_buf *buf)
         /*
          * In some error paths it's convenient to be able to "free" a NULL buf.
          */
-        if (!buf)
+        if (IS_ERR_OR_NULL(buf))
                 return;
 
         nvgpu_dma_free(g, buf->mem);