linux-kernel - [PATCH 08/10] dmapool: cleanup dma_pool

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Date:   Tue, 31 May 2022 14:22:21 -0400
From:   Tony Battersby <tonyb@...ernetics.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     iommu@...ts.linux-foundation.org, kernel-team@...com,
        Matthew Wilcox <willy@...radead.org>,
        Keith Busch <kbusch@...nel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Robin Murphy <robin.murphy@....com>,
        Tony Lindgren <tony@...mide.com>
Subject: [PATCH 08/10] dmapool: cleanup dma_pool_destroy

Remove a small amount of code duplication between dma_pool_destroy() and
pool_free_page() in preparation for adding more code without having to
duplicate it.  No functional changes.

Signed-off-by: Tony Battersby <tonyb@...ernetics.com>
---
 mm/dmapool.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 8749a9d7927e..58c11dcaa4e4 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -250,14 +250,25 @@ static inline bool is_page_busy(struct dma_page *page)
 	return page->in_use != 0;
 }
 
-static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
+static void pool_free_page(struct dma_pool *pool,
+			   struct dma_page *page,
+			   bool destroying_pool)
 {
+	void *vaddr = page->vaddr;
 	dma_addr_t dma = page->dma;
 
+	if (destroying_pool && is_page_busy(page)) {
+		dev_err(pool->dev,
+			"dma_pool_destroy %s, %p busy\n",
+			pool->name, vaddr);
+		/* leak the still-in-use consistent memory */
+	} else {
 #ifdef	DMAPOOL_DEBUG
-	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+		memset(vaddr, POOL_POISON_FREED, pool->allocation);
 #endif
-	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
+		dma_free_coherent(pool->dev, pool->allocation, vaddr, dma);
+	}
+
 	list_del(&page->page_list);
 	kfree(page);
 }
@@ -272,7 +283,7 @@ static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
  */
 void dma_pool_destroy(struct dma_pool *pool)
 {
-	struct dma_page *page, *tmp;
+	struct dma_page *page;
 	bool empty = false;
 
 	if (unlikely(!pool))
@@ -288,15 +299,10 @@ void dma_pool_destroy(struct dma_pool *pool)
 		device_remove_file(pool->dev, &dev_attr_pools);
 	mutex_unlock(&pools_reg_lock);
 
-	list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
-		if (is_page_busy(page)) {
-			dev_err(pool->dev, "%s %s, %p busy\n", __func__,
-				pool->name, page->vaddr);
-			/* leak the still-in-use consistent memory */
-			list_del(&page->page_list);
-			kfree(page);
-		} else
-			pool_free_page(pool, page);
+	while ((page = list_first_entry_or_null(&pool->page_list,
+						struct dma_page,
+						page_list))) {
+		pool_free_page(pool, page, true);
 	}
 
 	kfree(pool);
@@ -469,7 +475,7 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
 	page->offset = offset;
 	/*
 	 * Resist a temptation to do
-	 *    if (!is_page_busy(page)) pool_free_page(pool, page);
+	 *    if (!is_page_busy(page)) pool_free_page(pool, page, false);
 	 * Better have a few empty pages hang around.
 	 */
 	spin_unlock_irqrestore(&pool->lock, flags);
-- 
2.25.1