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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 <Felix.Kuehling@amd.com>
Reviewed-by: Oak Zeng <Oak.Zeng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Felix Kuehling 2019-08-30 00:10:34 -04:00 committed by Alex Deucher
parent 811bc15b49
commit cd05c86510
1 changed files with 8 additions and 0 deletions
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8
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
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@ -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; \
})