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mtd: nand: denali: use non-managed kmalloc() for DMA buffer

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As Russell and Lars stated in the discussion [1], using
devm_k*alloc() with DMA is not a good idea.

Let's use kmalloc (not kzalloc because no need for zero-out).
Also, allocate the buffer as late as possible because it must be
freed for any error that follows.

[1] https://lkml.org/lkml/2017/3/8/693

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Masahiro Yamada 2017-06-13 22:45:48 +09:00 committed by Boris Brezillon
parent 997cde2a22
commit 7d370b2c25
1 changed files with 17 additions and 9 deletions
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26
drivers/mtd/nand/denali.c
View file

@ -23,6 +23,7 @@
#include <linux/mutex.h>
#include <linux/mtd/mtd.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "denali.h"
@ -1352,13 +1353,6 @@ int denali_init(struct denali_nand_info *denali)
if (ret)
goto disable_irq;
denali->buf = devm_kzalloc(denali->dev, mtd->writesize + mtd->oobsize,
GFP_KERNEL);
if (!denali->buf) {
ret = -ENOMEM;
goto disable_irq;
}
if (ioread32(denali->flash_reg + FEATURES) & FEATURES__DMA)
denali->dma_avail = 1;
@ -1443,17 +1437,30 @@ int denali_init(struct denali_nand_info *denali)
if (ret)
goto disable_irq;
/*
* This buffer is DMA-mapped by denali_{read,write}_page_raw. Do not
* use devm_kmalloc() because the memory allocated by devm_ does not
* guarantee DMA-safe alignment.
*/
denali->buf = kmalloc(mtd->writesize + mtd->oobsize, GFP_KERNEL);
if (!denali->buf) {
ret = -ENOMEM;
goto disable_irq;
}
ret = nand_scan_tail(mtd);
if (ret)
goto disable_irq;
goto free_buf;
ret = mtd_device_register(mtd, NULL, 0);
if (ret) {
dev_err(denali->dev, "Failed to register MTD: %d\n", ret);
goto disable_irq;
goto free_buf;
}
return 0;
free_buf:
kfree(denali->buf);
disable_irq:
denali_disable_irq(denali);
@ -1467,6 +1474,7 @@ void denali_remove(struct denali_nand_info *denali)
struct mtd_info *mtd = nand_to_mtd(&denali->nand);
nand_release(mtd);
kfree(denali->buf);
denali_disable_irq(denali);
}
EXPORT_SYMBOL(denali_remove);