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gpu: nvgpu: Change va_node free behavior

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Decrement the ref count on all mapped_buffers belonging to a va_node
when a va_node is freed. This prevents userspace from leaking some
mapped_buffers in some cases.

This does prevent userspace from keeping a buffer around after freeing
a space allocation if the buffer in question is not otherwise ref
counted. Not sure if this is a bad thing for userspace or not.

Bug 1600686

Change-Id: I659ccbda5935d44086fd367bd2110f7d0f066194
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/676629
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>
This commit is contained in:
Alex Waterman
2015-01-22 12:48:10 -08:00
committed by Dan Willemsen
parent 9148a1e627
commit 4f693d032a
1 changed files with 5 additions and 4 deletions
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9
drivers/gpu/nvgpu/gk20a/mm_gk20a.c
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@@ -1,7 +1,7 @@
/*
* GK20A memory management
*
* Copyright (c) 2011-2014, NVIDIA CORPORATION. All rights reserved.
* Copyright (c) 2011-2015, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
@@ -2474,12 +2474,13 @@ int gk20a_vm_free_space(struct gk20a_as_share *as_share,
if (va_node) {
struct mapped_buffer_node *buffer, *n;
/* there is no need to unallocate the buffers in va. Just
* convert them into normal buffers */
/* Decrement the ref count on all buffers in this va_node. This
* allows userspace to let the kernel free mappings that are
* only used by this va_node. */
list_for_each_entry_safe(buffer, n,
&va_node->va_buffers_list, va_buffers_list) {
list_del_init(&buffer->va_buffers_list);
kref_put(&buffer->ref, gk20a_vm_unmap_locked_kref);
}
list_del(&va_node->reserved_va_list);