drm/vmwgfx: Use kref in vmw_bo_dirty

Rather than using an ad hoc reference count use kref which is atomic
and has underflow warnings.

Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patch.msgid.link/20251030193640.153697-1-ian.forbes@broadcom.com
This commit is contained in:
Ian Forbes 2025-10-30 14:36:40 -05:00 committed by Zack Rusin
parent 32b415a9dc
commit c1962742ff

View file

@ -32,22 +32,22 @@ enum vmw_bo_dirty_method {
/**
* struct vmw_bo_dirty - Dirty information for buffer objects
* @ref_count: Reference count for this structure. Must be first member!
* @start: First currently dirty bit
* @end: Last currently dirty bit + 1
* @method: The currently used dirty method
* @change_count: Number of consecutive method change triggers
* @ref_count: Reference count for this structure
* @bitmap_size: The size of the bitmap in bits. Typically equal to the
* nuber of pages in the bo.
* @bitmap: A bitmap where each bit represents a page. A set bit means a
* dirty page.
*/
struct vmw_bo_dirty {
struct kref ref_count;
unsigned long start;
unsigned long end;
enum vmw_bo_dirty_method method;
unsigned int change_count;
unsigned int ref_count;
unsigned long bitmap_size;
unsigned long bitmap[];
};
@ -221,7 +221,7 @@ int vmw_bo_dirty_add(struct vmw_bo *vbo)
int ret;
if (dirty) {
dirty->ref_count++;
kref_get(&dirty->ref_count);
return 0;
}
@ -235,7 +235,7 @@ int vmw_bo_dirty_add(struct vmw_bo *vbo)
dirty->bitmap_size = num_pages;
dirty->start = dirty->bitmap_size;
dirty->end = 0;
dirty->ref_count = 1;
kref_init(&dirty->ref_count);
if (num_pages < PAGE_SIZE / sizeof(pte_t)) {
dirty->method = VMW_BO_DIRTY_PAGETABLE;
} else {
@ -274,10 +274,8 @@ void vmw_bo_dirty_release(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
if (dirty && --dirty->ref_count == 0) {
kvfree(dirty);
if (dirty && kref_put(&dirty->ref_count, (void *)kvfree))
vbo->dirty = NULL;
}
}
/**