[v3,33/37] mtd: nand: allocate aligned buffers if NAND_OWN_BUFFERS is unset

Message ID 1490861708-27813-3-git-send-email-yamada.masahiro@socionext.com
State New
Headers show
Series
  • Untitled series #943
Related show

Commit Message

Masahiro Yamada March 30, 2017, 8:15 a.m.
Some NAND controllers are using DMA engine requiring a specific
buffer alignment.  The core provides no guarantee on the nand_buffers
pointers, which forces some drivers to allocate their own buffers
and pass the NAND_OWN_BUFFERS flag.

Rework the nand_buffers allocation logic to allocate each buffer
independently.  This should make most NAND controllers/DMA engine
happy, and allow us to get rid of these custom buf allocation in
NAND controller drivers.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

---

Changes in v3:
  - Reword git-log

Changes in v2:
  - Newly added

 drivers/mtd/nand/nand_base.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

-- 
2.7.4


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Comments

Leonard Crestez April 6, 2017, 2:08 p.m. | #1
On Thu, Mar 30, 2017 at 11:15 AM, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
> 
> Some NAND controllers are using DMA engine requiring a specific
> buffer alignment.  The core provides no guarantee on the nand_buffers
> pointers, which forces some drivers to allocate their own buffers
> and pass the NAND_OWN_BUFFERS flag.
> 
> Rework the nand_buffers allocation logic to allocate each buffer
> independently.  This should make most NAND controllers/DMA engine
> happy, and allow us to get rid of these custom buf allocation in
> NAND controller drivers.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

> @@ -4914,8 +4930,12 @@ void nand_cleanup(struct nand_chip *chip)
> >         /* Free bad block table memory */
>         kfree(chip->bbt);
> -       if (!(chip->options & NAND_OWN_BUFFERS))
> +       if (!(chip->options & NAND_OWN_BUFFERS)) {
> +               kfree(chip->buffers->databuf);
> +               kfree(chip->buffers->ecccode);
> +               kfree(chip->buffers->ecccalc);
>                 kfree(chip->buffers);
> +       }

It seems that chip->buffers might not be allocated at this point, for
example if nand_cleanup is called during a failed probe. You should
check if (chip->buffers != NULL) before freeing stuff inside it.

When attempting to run linux-next on various imx6qdl-sabreauto boards
they now panic on boot. This happens because they have nand chips in
devicetree which are not physically populated on the board. This
normally fails in nand_scan_ident but now crashes later in
nand_cleanup.

--
Regards,
Leonard

Patch hide | download patch | download mbox

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index f828ad7..e9d3195 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4613,13 +4613,25 @@  int nand_scan_tail(struct mtd_info *mtd)
 	}
 
 	if (!(chip->options & NAND_OWN_BUFFERS)) {
-		nbuf = kzalloc(sizeof(*nbuf) + mtd->writesize
-				+ mtd->oobsize * 3, GFP_KERNEL);
+		nbuf = kzalloc(sizeof(*nbuf), GFP_KERNEL);
 		if (!nbuf)
 			return -ENOMEM;
-		nbuf->ecccalc = (uint8_t *)(nbuf + 1);
-		nbuf->ecccode = nbuf->ecccalc + mtd->oobsize;
-		nbuf->databuf = nbuf->ecccode + mtd->oobsize;
+		nbuf->ecccalc = kmalloc(mtd->oobsize, GFP_KERNEL);
+		if (!nbuf->ecccalc) {
+			ret = -EINVAL;
+			goto err_free;
+		}
+		nbuf->ecccode = kmalloc(mtd->oobsize, GFP_KERNEL);
+		if (!nbuf->ecccode) {
+			ret = -EINVAL;
+			goto err_free;
+		}
+		nbuf->databuf = kmalloc(mtd->writesize + mtd->oobsize,
+					GFP_KERNEL);
+		if (!nbuf->databuf) {
+			ret = -EINVAL;
+			goto err_free;
+		}
 
 		chip->buffers = nbuf;
 	} else {
@@ -4862,8 +4874,12 @@  int nand_scan_tail(struct mtd_info *mtd)
 	/* Build bad block table */
 	return chip->scan_bbt(mtd);
 err_free:
-	if (!(chip->options & NAND_OWN_BUFFERS))
+	if (!(chip->options & NAND_OWN_BUFFERS)) {
+		kfree(chip->buffers->databuf);
+		kfree(chip->buffers->ecccode);
+		kfree(chip->buffers->ecccalc);
 		kfree(chip->buffers);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(nand_scan_tail);
@@ -4914,8 +4930,12 @@  void nand_cleanup(struct nand_chip *chip)
 
 	/* Free bad block table memory */
 	kfree(chip->bbt);
-	if (!(chip->options & NAND_OWN_BUFFERS))
+	if (!(chip->options & NAND_OWN_BUFFERS)) {
+		kfree(chip->buffers->databuf);
+		kfree(chip->buffers->ecccode);
+		kfree(chip->buffers->ecccalc);
 		kfree(chip->buffers);
+	}
 
 	/* Free bad block descriptor memory */
 	if (chip->badblock_pattern && chip->badblock_pattern->options