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9786b65bc6
When mapping ttm objects via drm_gem_ttm_mmap() helper
drm_gem_mmap_obj() will take an object reference. That gets
never released due to ttm having its own reference counting.
Fix that by dropping the gem object reference once the ttm mmap
completed (and ttm refcount got bumped).
For that to work properly the drm_gem_object_get() call in
drm_gem_ttm_mmap() must be moved so it happens before calling
obj->funcs->mmap(), otherwise the gem refcount would go down
to zero.
Fixes: 231927d939 ("drm/ttm: add drm_gem_ttm_mmap()")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20191113135612.19679-1-kraxel@redhat.com
85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#include <linux/module.h>
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#include <drm/drm_gem_ttm_helper.h>
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/**
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* DOC: overview
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*
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* This library provides helper functions for gem objects backed by
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* ttm.
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*/
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/**
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* drm_gem_ttm_print_info() - Print &ttm_buffer_object info for debugfs
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* @p: DRM printer
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* @indent: Tab indentation level
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* @gem: GEM object
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*
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* This function can be used as &drm_gem_object_funcs.print_info
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* callback.
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*/
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void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
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const struct drm_gem_object *gem)
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{
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static const char * const plname[] = {
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[ TTM_PL_SYSTEM ] = "system",
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[ TTM_PL_TT ] = "tt",
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[ TTM_PL_VRAM ] = "vram",
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[ TTM_PL_PRIV ] = "priv",
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[ 16 ] = "cached",
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[ 17 ] = "uncached",
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[ 18 ] = "wc",
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[ 19 ] = "contig",
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[ 21 ] = "pinned", /* NO_EVICT */
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[ 22 ] = "topdown",
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};
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const struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
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drm_printf_indent(p, indent, "placement=");
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drm_print_bits(p, bo->mem.placement, plname, ARRAY_SIZE(plname));
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drm_printf(p, "\n");
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if (bo->mem.bus.is_iomem) {
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drm_printf_indent(p, indent, "bus.base=%lx\n",
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(unsigned long)bo->mem.bus.base);
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drm_printf_indent(p, indent, "bus.offset=%lx\n",
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(unsigned long)bo->mem.bus.offset);
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}
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}
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EXPORT_SYMBOL(drm_gem_ttm_print_info);
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/**
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* drm_gem_ttm_mmap() - mmap &ttm_buffer_object
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* @gem: GEM object.
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* @vma: vm area.
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*
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* This function can be used as &drm_gem_object_funcs.mmap
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* callback.
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*/
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int drm_gem_ttm_mmap(struct drm_gem_object *gem,
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struct vm_area_struct *vma)
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{
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struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
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int ret;
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ret = ttm_bo_mmap_obj(vma, bo);
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if (ret < 0)
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return ret;
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/*
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* ttm has its own object refcounting, so drop gem reference
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* to avoid double accounting counting.
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*/
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drm_gem_object_put_unlocked(gem);
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return 0;
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}
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EXPORT_SYMBOL(drm_gem_ttm_mmap);
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MODULE_DESCRIPTION("DRM gem ttm helpers");
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MODULE_LICENSE("GPL");
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