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drm/panthor: Lock the VM resv before calling drm_gpuvm_bo_obtain_prealloc()

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drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our
pre-allocated BO if the <BO,VM> association exists. Given we
only have one ref on preallocated_vm_bo, drm_gpuvm_bo_destroy() will
be called immediately, and we have to hold the VM resv lock when
calling this function.

Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240913112722.492144-1-boris.brezillon@collabora.com
This commit is contained in:
Boris Brezillon 2024-09-13 13:27:22 +02:00
parent 2b55639a4e
commit fa998a9eac
1 changed files with 8 additions and 0 deletions
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8
drivers/gpu/drm/panthor/panthor_mmu.c
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@ -1251,9 +1251,17 @@ static int panthor_vm_prepare_map_op_ctx(struct panthor_vm_op_ctx *op_ctx,
goto err_cleanup;
}
/* drm_gpuvm_bo_obtain_prealloc() will call drm_gpuvm_bo_put() on our
* pre-allocated BO if the <BO,VM> association exists. Given we
* only have one ref on preallocated_vm_bo, drm_gpuvm_bo_destroy() will
* be called immediately, and we have to hold the VM resv lock when
* calling this function.
*/
dma_resv_lock(panthor_vm_resv(vm), NULL);
mutex_lock(&bo->gpuva_list_lock);
op_ctx->map.vm_bo = drm_gpuvm_bo_obtain_prealloc(preallocated_vm_bo);
mutex_unlock(&bo->gpuva_list_lock);
dma_resv_unlock(panthor_vm_resv(vm));
/* If the a vm_bo for this <VM,BO> combination exists, it already
* retains a pin ref, and we can release the one we took earlier.