From:   Keith Busch <kbusch@meta.com>
To:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <willy@infradead.org>, <hch@lst.de>, <tonyb@cybernetics.com>,
        <akpm@linux-foundation.org>
CC:     <kernel-team@meta.com>, Keith Busch <kbusch@kernel.org>
Subject: [PATCHv4 06/12] dmapool: move debug code to own functions
Date:   Thu, 26 Jan 2023 13:51:19 -0800
Message-ID: <20230126215125.4069751-7-kbusch@meta.com>
In-Reply-To: <20230126215125.4069751-1-kbusch@meta.com>
References: <20230126215125.4069751-1-kbusch@meta.com>
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From: Keith Busch <kbusch@kernel.org>

Clean up the normal path by moving the debug code outside it.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 mm/dmapool.c | 128 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 77 insertions(+), 51 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index eaed3ffb42aa8..30b069e999968 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -96,6 +96,78 @@ static ssize_t pools_show(struct device *dev, struct d=
evice_attribute *attr, cha
=20
 static DEVICE_ATTR_RO(pools);
=20
+#ifdef DMAPOOL_DEBUG
+static void pool_check_block(struct dma_pool *pool, void *retval,
+			     unsigned int offset, gfp_t mem_flags)
+{
+	int i;
+	u8 *data =3D retval;
+	/* page->offset is stored in first 4 bytes */
+	for (i =3D sizeof(offset); i < pool->size; i++) {
+		if (data[i] =3D=3D POOL_POISON_FREED)
+			continue;
+		dev_err(pool->dev, "%s %s, %p (corrupted)\n",
+			__func__, pool->name, retval);
+
+		/*
+		 * Dump the first 4 bytes even if they are not
+		 * POOL_POISON_FREED
+		 */
+		print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
+				data, pool->size, 1);
+		break;
+	}
+	if (!want_init_on_alloc(mem_flags))
+		memset(retval, POOL_POISON_ALLOCATED, pool->size);
+}
+
+static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
+			  void *vaddr, dma_addr_t dma)
+{
+	unsigned int offset =3D vaddr - page->vaddr;
+	unsigned int chain =3D page->offset;
+
+	if ((dma - page->dma) !=3D offset) {
+		dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n",
+			__func__, pool->name, vaddr, &dma);
+		return true;
+	}
+
+	while (chain < pool->allocation) {
+		if (chain !=3D offset) {
+			chain =3D *(int *)(page->vaddr + chain);
+			continue;
+		}
+		dev_err(pool->dev, "%s %s, dma %pad already free\n",
+			__func__, pool->name, &dma);
+		return true;
+	}
+	memset(vaddr, POOL_POISON_FREED, pool->size);
+	return false;
+}
+
+static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
+{
+	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+}
+#else
+static void pool_check_block(struct dma_pool *pool, void *retval,
+			     unsigned int offset, gfp_t mem_flags)
+
+{
+}
+
+static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
+			  void *vaddr, dma_addr_t dma)
+{
+	return false;
+}
+
+static void pool_init_page(struct dma_pool *pool, struct dma_page *page)
+{
+}
+#endif
+
 /**
  * dma_pool_create - Creates a pool of consistent memory blocks, for dma=
.
  * @name: name of pool, for diagnostics
@@ -223,9 +295,7 @@ static struct dma_page *pool_alloc_page(struct dma_po=
ol *pool, gfp_t mem_flags)
 	page->vaddr =3D dma_alloc_coherent(pool->dev, pool->allocation,
 					 &page->dma, mem_flags);
 	if (page->vaddr) {
-#ifdef	DMAPOOL_DEBUG
-		memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
-#endif
+		pool_init_page(pool, page);
 		pool_initialise_page(pool, page);
 		page->in_use =3D 0;
 		page->offset =3D 0;
@@ -245,9 +315,7 @@ static void pool_free_page(struct dma_pool *pool, str=
uct dma_page *page)
 {
 	dma_addr_t dma =3D page->dma;
=20
-#ifdef	DMAPOOL_DEBUG
-	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
-#endif
+	pool_init_page(pool, page);
 	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
 	list_del(&page->page_list);
 	kfree(page);
@@ -336,29 +404,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t me=
m_flags,
 	page->offset =3D *(int *)(page->vaddr + offset);
 	retval =3D offset + page->vaddr;
 	*handle =3D offset + page->dma;
-#ifdef	DMAPOOL_DEBUG
-	{
-		int i;
-		u8 *data =3D retval;
-		/* page->offset is stored in first 4 bytes */
-		for (i =3D sizeof(page->offset); i < pool->size; i++) {
-			if (data[i] =3D=3D POOL_POISON_FREED)
-				continue;
-			dev_err(pool->dev, "%s %s, %p (corrupted)\n",
-				__func__, pool->name, retval);
-
-			/*
-			 * Dump the first 4 bytes even if they are not
-			 * POOL_POISON_FREED
-			 */
-			print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
-					data, pool->size, 1);
-			break;
-		}
-	}
-	if (!want_init_on_alloc(mem_flags))
-		memset(retval, POOL_POISON_ALLOCATED, pool->size);
-#endif
+	pool_check_block(pool, retval, offset, mem_flags);
 	spin_unlock_irqrestore(&pool->lock, flags);
=20
 	if (want_init_on_alloc(mem_flags))
@@ -394,7 +440,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr=
, dma_addr_t dma)
 {
 	struct dma_page *page;
 	unsigned long flags;
-	unsigned int offset;
=20
 	spin_lock_irqsave(&pool->lock, flags);
 	page =3D pool_find_page(pool, dma);
@@ -405,35 +450,16 @@ void dma_pool_free(struct dma_pool *pool, void *vad=
dr, dma_addr_t dma)
 		return;
 	}
=20
-	offset =3D vaddr - page->vaddr;
 	if (want_init_on_free())
 		memset(vaddr, 0, pool->size);
-#ifdef	DMAPOOL_DEBUG
-	if ((dma - page->dma) !=3D offset) {
+	if (pool_page_err(pool, page, vaddr, dma)) {
 		spin_unlock_irqrestore(&pool->lock, flags);
-		dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n",
-			__func__, pool->name, vaddr, &dma);
 		return;
 	}
-	{
-		unsigned int chain =3D page->offset;
-		while (chain < pool->allocation) {
-			if (chain !=3D offset) {
-				chain =3D *(int *)(page->vaddr + chain);
-				continue;
-			}
-			spin_unlock_irqrestore(&pool->lock, flags);
-			dev_err(pool->dev, "%s %s, dma %pad already free\n",
-				__func__, pool->name, &dma);
-			return;
-		}
-	}
-	memset(vaddr, POOL_POISON_FREED, pool->size);
-#endif
=20
 	page->in_use--;
 	*(int *)vaddr =3D page->offset;
-	page->offset =3D offset;
+	page->offset =3D vaddr - page->vaddr;
 	/*
 	 * Resist a temptation to do
 	 *    if (!is_page_busy(page)) pool_free_page(pool, page);
--=20
2.30.2