3 files changed, 26 insertions, 9 deletions

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 6f7edb3590ef..02ac34537df9 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -843,11 +843,13 @@ struct damon_attrs {
  * including damon_call() and damos_walk().
  *
  * @ops:	Set of monitoring operations for given use cases.
+ * @probes:	Head of probes (&damon_probe) list.
  * @addr_unit:	Scale factor for core to ops address conversion.
  * @min_region_sz:	Minimum region size.
  * @pause:	Pause kdamond main loop.
  * @adaptive_targets:	Head of monitoring targets (&damon_target) list.
  * @schemes:		Head of schemes (&damos) list.
+ * @rnd_state:	Per-ctx PRNG state for damon_rand().
  */
 struct damon_ctx {
 	struct damon_attrs attrs;
@@ -905,7 +907,6 @@ struct damon_ctx {
 	struct list_head adaptive_targets;
 	struct list_head schemes;
 
-	/* Per-ctx PRNG state for damon_rand(); kdamond is the sole consumer. */
 	struct rnd_state rnd_state;
 };
 
@@ -1065,9 +1066,13 @@ static inline bool damon_target_has_pid(const struct damon_ctx *ctx)
 
 static inline unsigned int damon_max_nr_accesses(const struct damon_attrs *attrs)
 {
-	/* {aggr,sample}_interval are unsigned long, hence could overflow */
-	return min(attrs->aggr_interval / attrs->sample_interval,
+	unsigned long sample_interval;
+	unsigned long max_nr_accesses;
+
+	sample_interval = attrs->sample_interval ? : 1;
+	max_nr_accesses = min(attrs->aggr_interval / sample_interval,
 			(unsigned long)UINT_MAX);
+	return max_nr_accesses ? : 1;
 }
 
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d10897b3a1e3..50ce731a2b78 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2444,6 +2444,11 @@ static inline struct mnt_idmap *file_mnt_idmap(const struct file *file)
 	return mnt_idmap(file->f_path.mnt);
 }
 
+static inline bool file_owner_or_capable(const struct file *file)
+{
+	return inode_owner_or_capable(file_mnt_idmap(file), file_inode(file));
+}
+
 /**
  * is_idmapped_mnt - check whether a mount is mapped
  * @mnt: the mount to check
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 61e876e255e8..f23d4b218da0 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -120,14 +120,18 @@ struct page_ext_iter {
  * page_ext_iter_begin() - Prepare for iterating through page extensions.
  * @iter: page extension iterator.
  * @pfn: PFN of the page we're interested in.
+ * @count: maximum number of page extensions to return.
  *
  * Must be called with RCU read lock taken.
  *
  * Return: NULL if no page_ext exists for this page.
  */
 static inline struct page_ext *page_ext_iter_begin(struct page_ext_iter *iter,
-						unsigned long pfn)
+		unsigned long pfn, unsigned long count)
 {
+	if (!count)
+		return NULL;
+
 	iter->index = 0;
 	iter->start_pfn = pfn;
 	iter->page_ext = page_ext_lookup(pfn);
@@ -138,19 +142,22 @@ static inline struct page_ext *page_ext_iter_begin(struct page_ext_iter *iter,
 /**
  * page_ext_iter_next() - Get next page extension
  * @iter: page extension iterator.
+ * @count: maximum number of page extensions to return.
  *
  * Must be called with RCU read lock taken.
  *
  * Return: NULL if no next page_ext exists.
  */
-static inline struct page_ext *page_ext_iter_next(struct page_ext_iter *iter)
+static inline struct page_ext *page_ext_iter_next(struct page_ext_iter *iter,
+		unsigned long count)
 {
 	unsigned long pfn;
 
 	if (WARN_ON_ONCE(!iter->page_ext))
 		return NULL;
 
-	iter->index++;
+	if (++iter->index >= count)
+		return NULL;
 	pfn = iter->start_pfn + iter->index;
 
 	if (page_ext_iter_next_fast_possible(pfn))
@@ -183,9 +190,9 @@ static inline struct page_ext *page_ext_iter_get(const struct page_ext_iter *ite
  * IMPORTANT: must be called with RCU read lock taken.
  */
 #define for_each_page_ext(__page, __pgcount, __page_ext, __iter) \
-	for (__page_ext = page_ext_iter_begin(&__iter, page_to_pfn(__page));\
-		__page_ext && __iter.index < __pgcount;          \
-		__page_ext = page_ext_iter_next(&__iter))
+	for (__page_ext = page_ext_iter_begin(&__iter, page_to_pfn(__page), __pgcount); \
+		__page_ext; \
+		__page_ext = page_ext_iter_next(&__iter, __pgcount))
 
 #else /* !CONFIG_PAGE_EXTENSION */
 struct page_ext;