Reviewed-by: Oak Zeng
Regards,
Oak
-Original Message-
From: amd-gfx On Behalf Of Kuehling,
Felix
Sent: Friday, August 30, 2019 1:15 AM
To: amd-gfx@lists.freedesktop.org
Subject: [PATCH 2/2] drm/amdgpu: Disable page faults while reading user wptrs
These wptrs must be pinned and GPU accessible when this is called from hqd_load
functions. So they should never fault. This resolves a circular lock dependency
issue involving four locks including the DQM lock and mmap_sem.
Signed-off-by: Felix Kuehling
---
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 8
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index 1af8f83f7e02..c003d9275837 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -179,10 +179,17 @@ uint64_t amdgpu_amdkfd_get_mmio_remap_phys_addr(struct
kgd_dev *kgd); uint32_t amdgpu_amdkfd_get_num_gws(struct kgd_dev *kgd);
uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev *dst, struct kgd_dev
*src);
+/* Read user wptr from a specified user address space with page fault
+ * disabled. The memory must be pinned and mapped to the hardware when
+ * this is called in hqd_load functions, so it should never fault in
+ * the first place. This resolves a circular lock dependency involving
+ * four locks, including the DQM lock and mmap_sem.
+ */
#define read_user_wptr(mmptr, wptr, dst) \
({ \
bool valid = false; \
if ((mmptr) && (wptr)) {\
+ pagefault_disable();\
if ((mmptr) == current->mm) { \
valid = !get_user((dst), (wptr)); \
} else if (current->mm == NULL) { \
@@ -190,6 +197,7 @@ uint8_t amdgpu_amdkfd_get_xgmi_hops_count(struct kgd_dev
*dst, struct kgd_dev *s
valid = !get_user((dst), (wptr)); \
unuse_mm(mmptr);\
} \
+ pagefault_enable(); \
} \
valid; \
})
--
2.17.1
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