mm: remove struct pagevec

All users are now converted to use the folio_batch so we can get rid of
this data structure.

Link: https://lkml.kernel.org/r/20230621164557.3510324-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Matthew Wilcox (Oracle)

include/linux/pagevec.h

@@ -3,65 +3,18 @@
  * include/linux/pagevec.h
  *
  * In many places it is efficient to batch an operation up against multiple
- * pages.  A pagevec is a multipage container which is used for that.
+ * folios.  A folio_batch is a container which is used for that.
  */
 
 #ifndef _LINUX_PAGEVEC_H
 #define _LINUX_PAGEVEC_H
 
-#include <linux/xarray.h>
+#include <linux/types.h>
 
-/* 15 pointers + header align the pagevec structure to a power of two */
+/* 15 pointers + header align the folio_batch structure to a power of two */
 #define PAGEVEC_SIZE	15
 
-struct page;
 struct folio;
-struct address_space;
-
-/* Layout must match folio_batch */
-struct pagevec {
-	unsigned char nr;
-	bool percpu_pvec_drained;
-	struct page *pages[PAGEVEC_SIZE];
-};
-
-void __pagevec_release(struct pagevec *pvec);
-
-static inline void pagevec_init(struct pagevec *pvec)
-{
-	pvec->nr = 0;
-	pvec->percpu_pvec_drained = false;
-}
-
-static inline void pagevec_reinit(struct pagevec *pvec)
-{
-	pvec->nr = 0;
-}
-
-static inline unsigned pagevec_count(struct pagevec *pvec)
-{
-	return pvec->nr;
-}
-
-static inline unsigned pagevec_space(struct pagevec *pvec)
-{
-	return PAGEVEC_SIZE - pvec->nr;
-}
-
-/*
- * Add a page to a pagevec.  Returns the number of slots still available.
- */
-static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
-{
-	pvec->pages[pvec->nr++] = page;
-	return pagevec_space(pvec);
-}
-
-static inline void pagevec_release(struct pagevec *pvec)
-{
-	if (pagevec_count(pvec))
-		__pagevec_release(pvec);
-}
 
 /**
  * struct folio_batch - A collection of folios.
@@ -78,11 +31,6 @@ struct folio_batch {
 	struct folio *folios[PAGEVEC_SIZE];
 };
 
-/* Layout must match pagevec */
-static_assert(sizeof(struct pagevec) == sizeof(struct folio_batch));
-static_assert(offsetof(struct pagevec, pages) ==
-		offsetof(struct folio_batch, folios));
-
 /**
  * folio_batch_init() - Initialise a batch of folios
  * @fbatch: The folio batch.
@@ -127,10 +75,7 @@ static inline unsigned folio_batch_add(struct folio_batch *fbatch,
 	return folio_batch_space(fbatch);
 }
 
-static inline void __folio_batch_release(struct folio_batch *fbatch)
-{
-	__pagevec_release((struct pagevec *)fbatch);
-}
+void __folio_batch_release(struct folio_batch *pvec);
 
 static inline void folio_batch_release(struct folio_batch *fbatch)
 {

mm/swap.c

@@ -1044,25 +1044,25 @@ void release_pages(release_pages_arg arg, int nr)
 EXPORT_SYMBOL(release_pages);
 
 /*
- * The pages which we're about to release may be in the deferred lru-addition
+ * The folios which we're about to release may be in the deferred lru-addition
  * queues.  That would prevent them from really being freed right now.  That's
- * OK from a correctness point of view but is inefficient - those pages may be
+ * OK from a correctness point of view but is inefficient - those folios may be
  * cache-warm and we want to give them back to the page allocator ASAP.
  *
- * So __pagevec_release() will drain those queues here.
+ * So __folio_batch_release() will drain those queues here.
  * folio_batch_move_lru() calls folios_put() directly to avoid
  * mutual recursion.
  */
-void __pagevec_release(struct pagevec *pvec)
+void __folio_batch_release(struct folio_batch *fbatch)
 {
-	if (!pvec->percpu_pvec_drained) {
+	if (!fbatch->percpu_pvec_drained) {
 		lru_add_drain();
-		pvec->percpu_pvec_drained = true;
+		fbatch->percpu_pvec_drained = true;
 	}
-	release_pages(pvec->pages, pagevec_count(pvec));
-	pagevec_reinit(pvec);
+	release_pages(fbatch->folios, folio_batch_count(fbatch));
+	folio_batch_reinit(fbatch);
 }
-EXPORT_SYMBOL(__pagevec_release);
+EXPORT_SYMBOL(__folio_batch_release);
 
 /**
  * folio_batch_remove_exceptionals() - Prune non-folios from a batch.