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>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index de6c8045c85b66939e86c15601a97304b037abb6..c796d0e4039a7d3de41edef46a299874e15babb7 100644 (file)
--- 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