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Groups > linux.kernel > #1659705

[PATCH v5 22/23] mtd: nand: denali: use non-managed kmalloc() for DMA buffer

From Masahiro Yamada <yamada.masahiro@socionext.com>
Newsgroups linux.kernel
Subject [PATCH v5 22/23] mtd: nand: denali: use non-managed kmalloc() for DMA buffer
Date 2017-06-07 14:00 +0200
Message-ID <tPHMZ-68d-7@gated-at.bofh.it> (permalink)
References <tPHMZ-68d-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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>
---

Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
  - Newly added

 drivers/mtd/nand/denali.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
index 963638693850..904f859e19b6 100644
--- a/drivers/mtd/nand/denali.c
+++ b/drivers/mtd/nand/denali.c
@@ -23,6 +23,7 @@
 #include <linux/mutex.h>
 #include <linux/mtd/mtd.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 
 #include "denali.h"
 
@@ -1386,13 +1387,6 @@ 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;
 
@@ -1477,17 +1471,30 @@ 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);
 
@@ -1501,6 +1508,7 @@ 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);
-- 
2.7.4

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Thread

[PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 22/23] mtd: nand: denali: use non-managed kmalloc() for DMA buffer Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 15/23] mtd: nand: denali: use interrupt instead of polling for bank reset Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 16/23] mtd: nand: denali: propagate page to helpers via function argument Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 18/23] mtd: nand: denali: use flag instead of register macro for direction Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 21/23] mtd: nand: denali: skip driver internal bounce buffer when possible Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 11/23] mtd: nand: denali: fix NAND_CMD_STATUS handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 19/23] mtd: nand: denali: fix raw and oob accessors for syndrome page layout Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
    Re: [PATCH v5 19/23] mtd: nand: denali: fix raw and oob accessors  for syndrome page layout Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-07 16:10 +0200
      Re: [PATCH v5 19/23] mtd: nand: denali: fix raw and oob accessors for  syndrome page layout Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 13:30 +0200
        Re: [PATCH v5 19/23] mtd: nand: denali: fix raw and oob accessors for  syndrome page layout Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-13 06:50 +0200
  [PATCH v5 09/23] mtd: nand: denali: handle timing parameters by setup_data_interface() Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 14/23] mtd: nand: denali: fix bank reset function to detect the number of chips Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 12/23] mtd: nand: denali: fix NAND_CMD_PARAM handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 17/23] mtd: nand: denali: merge struct nand_buf into struct denali_nand_info Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 06/23] mtd: nand: denali: set NAND_ECC_CUSTOM_PAGE_ACCESS Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
    Re: [PATCH v5 06/23] mtd: nand: denali: set  NAND_ECC_CUSTOM_PAGE_ACCESS Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-07 15:30 +0200
      Re: [PATCH v5 06/23] mtd: nand: denali: set NAND_ECC_CUSTOM_PAGE_ACCESS Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 09:40 +0200
  [PATCH v5 05/23] mtd: nand: denali_dt: add compatible strings for UniPhier SoC variants Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
    Re: [PATCH v5 05/23] mtd: nand: denali_dt: add compatible strings  for UniPhier SoC variants Rob Herring <robh@kernel.org> - 2017-06-07 21:10 +0200
  [PATCH v5 23/23] mtd: nand: denali: enable bad block table scan Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 01/23] mtd: nand: add generic helpers to check, match, maximize ECC settings Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 20/23] mtd: nand: denali: support hardware-assisted erased page detection Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
    Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-07 16:00 +0200
      Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 08:20 +0200
        Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 09:20 +0200
          Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 12:50 +0200
            Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 13:30 +0200
              Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 15:00 +0200
                Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 17:50 +0200
                Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 19:30 +0200
                Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 19:40 +0200
                Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-09 10:00 +0200
                Re: [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-13 06:50 +0200
  [PATCH v5 04/23] mtd: nand: denali: remove Toshiba and Hynix specific fixup code Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 13/23] mtd: nand: denali: switch over to cmd_ctrl instead of cmdfunc Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:00 +0200
  [PATCH v5 02/23] mtd: nand: add a shorthand to generate nand_ecc_caps structure Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:10 +0200
  [PATCH v5 03/23] mtd: nand: denali: avoid hard-coding ECC step, strength, bytes Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:10 +0200
  [PATCH v5 07/23] mtd: nand: denali: do not propagate NAND_STATUS_FAIL to waitfunc() Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-07 14:10 +0200
    Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate  NAND_STATUS_FAIL to waitfunc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-07 15:40 +0200
      Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate  NAND_STATUS_FAIL to waitfunc() Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 08:20 +0200
        Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate  NAND_STATUS_FAIL to waitfunc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 09:10 +0200
          Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate  NAND_STATUS_FAIL to waitfunc() Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 11:50 +0200
            Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate  NAND_STATUS_FAIL to waitfunc() Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 12:10 +0200
  Re: [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 08:20 +0200
    Re: [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 09:20 +0200
    Re: [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-08 09:20 +0200
      Re: [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-08 09:20 +0200
      Re: [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-06-11 22:20 +0200

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