mtd: nand: allocate aligned buffers if NAND_OWN_BUFFERS is unset

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>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

1 files changed, 32 insertions, 9 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index de6c8045c85b..c796d0e4039a 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4495,7 +4495,7 @@ int nand_scan_tail(struct mtd_info *mtd)
 {
         struct nand_chip *chip = mtd_to_nand(mtd);
         struct nand_ecc_ctrl *ecc = &chip->ecc;
-        struct nand_buffers *nbuf;
+        struct nand_buffers *nbuf = NULL;
         int ret;
 
         /* New bad blocks should be marked in OOB, flash-based BBT, or both */
@@ -4509,13 +4509,28 @@ 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 = -ENOMEM;
+                        goto err_free;
+                }
+
+                nbuf->ecccode = kmalloc(mtd->oobsize, GFP_KERNEL);
+                if (!nbuf->ecccode) {
+                        ret = -ENOMEM;
+                        goto err_free;
+                }
+
+                nbuf->databuf = kmalloc(mtd->writesize + mtd->oobsize,
+                                        GFP_KERNEL);
+                if (!nbuf->databuf) {
+                        ret = -ENOMEM;
+                        goto err_free;
+                }
 
                 chip->buffers = nbuf;
         } else {
@@ -4755,8 +4770,12 @@ 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))
-                kfree(chip->buffers);
+        if (nbuf) {
+                kfree(nbuf->databuf);
+                kfree(nbuf->ecccode);
+                kfree(nbuf->ecccalc);
+                kfree(nbuf);
+        }
         return ret;
 }
 EXPORT_SYMBOL(nand_scan_tail);
@@ -4807,8 +4826,12 @@ 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) && chip->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