linux-kernel - [PATCH 2/2] mtd: rawnand: use bounce buffer when vmalloced data buf detected

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Message-Id: <20190906194719.15761-2-kdasu.kdev@gmail.com>
Date:   Fri,  6 Sep 2019 15:47:16 -0400
From:   Kamal Dasu <kdasu.kdev@...il.com>
To:     kdasu.kdev@...il.com
Cc:     Brian Norris <computersforpeace@...il.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Marek Vasut <marek.vasut@...il.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Boris Brezillon <bbrezillon@...nel.org>,
        Frieder Schrempf <frieder.schrempf@...tron.de>,
        linux-mtd@...ts.infradead.org,
        bcm-kernel-feedback-list@...adcom.com, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] mtd: rawnand: use bounce buffer when vmalloced data buf detected

For controller drivers that use DMA and set NAND_USE_BOUNCE_BUFFER
option use data buffers that are not vmalloced, aligned and have
valid virtual address to be able to do DMA transfers. This change
adds additional check and makes use of data buffer allocated
in nand_base driver when it is passed a vmalloced data buffer for
DMA transfers.

Signed-off-by: Kamal Dasu <kdasu.kdev@...il.com>
---
 drivers/mtd/nand/raw/nand_base.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 91f046d4d452..46f6965a896a 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -45,6 +45,12 @@
 
 #include "internals.h"
 
+static int nand_need_bounce_buf(const void *buf, struct nand_chip *chip)
+{
+	return !virt_addr_valid(buf) || is_vmalloc_addr(buf) ||
+		!IS_ALIGNED((unsigned long)buf, chip->buf_align);
+}
+
 /* Define default oob placement schemes for large and small page devices */
 static int nand_ooblayout_ecc_sp(struct mtd_info *mtd, int section,
 				 struct mtd_oob_region *oobregion)
@@ -3183,9 +3189,7 @@ static int nand_do_read_ops(struct nand_chip *chip, loff_t from,
 		if (!aligned)
 			use_bufpoi = 1;
 		else if (chip->options & NAND_USE_BOUNCE_BUFFER)
-			use_bufpoi = !virt_addr_valid(buf) ||
-				     !IS_ALIGNED((unsigned long)buf,
-						 chip->buf_align);
+			use_bufpoi = nand_need_bounce_buf(buf, chip);
 		else
 			use_bufpoi = 0;
 
@@ -4009,9 +4013,7 @@ static int nand_do_write_ops(struct nand_chip *chip, loff_t to,
 		if (part_pagewr)
 			use_bufpoi = 1;
 		else if (chip->options & NAND_USE_BOUNCE_BUFFER)
-			use_bufpoi = !virt_addr_valid(buf) ||
-				     !IS_ALIGNED((unsigned long)buf,
-						 chip->buf_align);
+			use_bufpoi = nand_need_bounce_buf(buf, chip);
 		else
 			use_bufpoi = 0;
 
-- 
2.17.1