dmapool: consolidate page initialization

Various fields of the dma pool are set in different places. Move it all
to one function.

Link: https://lkml.kernel.org/r/20230126215125.4069751-9-kbusch@meta.com
Fixes: 2d55c16c ("dmapool: create/destroy cleanup")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/dmapool.c

@@ -274,6 +274,9 @@ static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
 	unsigned int offset = 0;
 	unsigned int next_boundary = pool->boundary;
 
+	pool_init_page(pool, page);
+	page->in_use = 0;
+	page->offset = 0;
 	do {
 		unsigned int next = offset + pool->size;
 		if (unlikely((next + pool->size) >= next_boundary)) {
@@ -300,11 +303,7 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
 		return NULL;
 	}
 
-	pool_init_page(pool, page);
 	pool_initialise_page(pool, page);
-	page->in_use = 0;
-	page->offset = 0;
-
 	return page;
 }