On 7/7/23 13:00, Boris Brezillon wrote:
On Fri, 30 Jun 2023 00:25:18 +0200
Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
+/**
+ * drm_gpuva_for_each_va_range - iternator to walk over a range of &drm_gpuvas
+ * @va__: &drm_gpuva structure to assign to in each iteration step
+ * @mgr__: &drm_gpuva_manager to walk over
+ * @start__: starting offset, the first gpuva will overlap this
+ * @end__: ending offset, the last gpuva will start before this (but may
+ * overlap)
+ *
+ * This iterator walks over all &drm_gpuvas in the &drm_gpuva_manager that lie
+ * between @start__ and @end__. It is implemented similarly to list_for_each(),
+ * but is using the &drm_gpuva_manager's internal interval tree to accelerate
+ * the search for the starting &drm_gpuva, and hence isn't safe against removal
+ * of elements. It assumes that @end__ is within (or is the upper limit of) the
+ * &drm_gpuva_manager. This iterator does not skip over the &drm_gpuva_manager's
+ * @kernel_alloc_node.
+ */
+#define drm_gpuva_for_each_va_range(va__, mgr__, start__, end__) \
+ for (va__ = drm_gpuva_find_first((mgr__), (start__), (end__)); \
drm_gpuva_find_first() takes the range size as its last argument, not
the range end:
for (va__ = drm_gpuva_find_first((mgr__), (start__), (end__) - (start__)); \
Good catch! Originally this was
drm_gpuva_it_iter_first(&(mgr)->rb.tree, (start__), (end__) - 1)
but then I changed it since I did not want to expose the interval tree
functions directly.
+ va__ && (va__->va.addr < (end__)) && \
+ !list_entry_is_head(va__, &(mgr__)->rb.list, rb.entry); \
+ va__ = list_next_entry(va__, rb.entry))
If you define:
static inline struct drm_gpuva *
drm_gpuva_next(struct drm_gpuva *va)
{
if (va && !list_is_last(&va->rb.entry, &va->mgr->rb.list))
return list_next_entry(va, rb.entry);
return NULL;
} >
the for loop becomes a bit more readable:
Yes, it would. However, I don't want it to be confused with
drm_gpuva_find_next(). Maybe I should rename the latter to something
like drm_gpuva_find_next_neighbor() then.
for (va__ = drm_gpuva_find_first((mgr__), (start__), (end__) - (start__)); \
va__ && (va__->va.addr < (end__)); \
va__ = drm_gpuva_next(va__))
+
+/**
+ * drm_gpuva_for_each_va_range_safe - iternator to safely walk over a range of
+ * &drm_gpuvas
+ * @va__: &drm_gpuva to assign to in each iteration step
+ * @next__: another &drm_gpuva to use as temporary storage
+ * @mgr__: &drm_gpuva_manager to walk over
+ * @start__: starting offset, the first gpuva will overlap this
+ * @end__: ending offset, the last gpuva will start before this (but may
+ * overlap)
+ *
+ * This iterator walks over all &drm_gpuvas in the &drm_gpuva_manager that lie
+ * between @start__ and @end__. It is implemented similarly to
+ * list_for_each_safe(), but is using the &drm_gpuva_manager's internal interval
+ * tree to accelerate the search for the starting &drm_gpuva, and hence is safe
+ * against removal of elements. It assumes that @end__ is within (or is the
+ * upper limit of) the &drm_gpuva_manager. This iterator does not skip over the
+ * &drm_gpuva_manager's @kernel_alloc_node.
+ */
+#define drm_gpuva_for_each_va_range_safe(va__, next__, mgr__, start__, end__) \
+ for (va__ = drm_gpuva_find_first((mgr__), (start__), (end__)), \
+ next__ = va ? list_next_entry(va__, rb.entry) : NULL; \
+ va__ && (va__->va.addr < (end__)) && \
+ !list_entry_is_head(va__, &(mgr__)->rb.list, rb.entry); \
+ va__ = next__, next__ = list_next_entry(va__, rb.entry))
And this is the safe version using the drm_gpuva_next() helper:
for (va__ = drm_gpuva_find_first((mgr__), (start__), (end__) - (start__)), \
next__ = drm_gpuva_next(va__); \
va__ && (va__->va.addr < (end__)); \
va__ = next__, next__ = drm_gpuva_next(va__))
Those changes fixed an invalid pointer access I had in the sm_unmap()
path.
Sorry you did run into this bug.
- Danilo
