+ dmapool-simplify-freeing.patch added to mm-unstable branch

+ dmapool-simplify-freeing.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: dmapool: simplify freeing
has been added to the -mm mm-unstable branch.  Its filename is
     dmapool-simplify-freeing.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/dmapool-simplify-freeing.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Keith Busch <kbusch@kernel.org>
Subject: dmapool: simplify freeing
Date: Thu, 26 Jan 2023 13:51:22 -0800

The actions for busy and not busy are mostly the same, so combine these
and remove the unnecessary function.  Also, the pool is about to be freed
so there's no need to poison the page data since we only check for poison
on alloc, which can't be done on a freed pool.

Link: https://lkml.kernel.org/r/20230126215125.4069751-10-kbusch@meta.com
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 |   22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

--- a/mm/dmapool.c~dmapool-simplify-freeing
+++ a/mm/dmapool.c
@@ -312,16 +312,6 @@ static inline bool is_page_busy(struct d
 	return page->in_use != 0;
 }
 
-static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
-{
-	dma_addr_t dma = page->dma;
-
-	pool_init_page(pool, page);
-	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
-	list_del(&page->page_list);
-	kfree(page);
-}
-
 /**
  * dma_pool_destroy - destroys a pool of dma memory blocks.
  * @pool: dma pool that will be destroyed
@@ -349,14 +339,14 @@ void dma_pool_destroy(struct dma_pool *p
 	mutex_unlock(&pools_reg_lock);
 
 	list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) {
-		if (is_page_busy(page)) {
+		if (!is_page_busy(page))
+			dma_free_coherent(pool->dev, pool->allocation,
+					  page->vaddr, page->dma);
+		else
 			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);
+		list_del(&page->page_list);
+		kfree(page);
 	}
 
 	kfree(pool);
_

Patches currently in -mm which might be from kbusch@kernel.org are

dmapool-add-alloc-free-performance-test.patch
dmapool-move-debug-code-to-own-functions.patch
dmapool-rearrange-page-alloc-failure-handling.patch
dmapool-consolidate-page-initialization.patch
dmapool-simplify-freeing.patch
dmapool-dont-memset-on-free-twice.patch
dmapool-link-blocks-across-pages.patch
dmapool-create-destroy-cleanup.patch