linux-kernel - [PATCH v2 2/5] firmware: google: memconsole: Use devm

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Date:   Fri, 10 May 2019 14:24:53 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Wei-Ning Huang <wnhuang@...omium.org>,
        Julius Werner <jwerner@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        Samuel Holland <samuel@...lland.org>,
        Guenter Roeck <groeck@...omium.org>
Subject: [PATCH v2 2/5] firmware: google: memconsole: Use devm_memremap()

Use the devm version of memremap so that we can delete the unmapping
code in driver remove, but more importantly so that we can unmap this
memory region if memconsole_sysfs_init() errors out for some reason.

Cc: Wei-Ning Huang <wnhuang@...omium.org>
Cc: Julius Werner <jwerner@...omium.org>
Cc: Brian Norris <briannorris@...omium.org>
Cc: Samuel Holland <samuel@...lland.org>
Cc: Guenter Roeck <groeck@...omium.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---

Quoting Stephen Boyd (2019-05-10 11:01:48)
> diff --git a/drivers/firmware/google/memconsole-coreboot.c b/drivers/firmware/google/memconsole-coreboot.c
> index 86331807f1d5..0b29b27b86f5 100644
> --- a/drivers/firmware/google/memconsole-coreboot.c
> +++ b/drivers/firmware/google/memconsole-coreboot.c
> @@ -85,7 +85,7 @@ static int memconsole_probe(struct coreboot_device *dev)
>  
>         /* Read size only once to prevent overrun attack through /dev/mem. */
>         cbmem_console_size = tmp_cbmc->size_dont_access_after_boot;
> -       cbmem_console = memremap(dev->cbmem_ref.cbmem_addr,
> +       cbmem_console = devm_memremap(&dev->dev, dev->cbmem_ref.cbmem_addr,

Whoops, this returns an error pointer now. Here's an updated patch.

 drivers/firmware/google/memconsole-coreboot.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/google/memconsole-coreboot.c b/drivers/firmware/google/memconsole-coreboot.c
index 86331807f1d5..cc3797f1ba85 100644
--- a/drivers/firmware/google/memconsole-coreboot.c
+++ b/drivers/firmware/google/memconsole-coreboot.c
@@ -85,13 +85,13 @@ static int memconsole_probe(struct coreboot_device *dev)
 
 	/* Read size only once to prevent overrun attack through /dev/mem. */
 	cbmem_console_size = tmp_cbmc->size_dont_access_after_boot;
-	cbmem_console = memremap(dev->cbmem_ref.cbmem_addr,
+	cbmem_console = devm_memremap(&dev->dev, dev->cbmem_ref.cbmem_addr,
 				 cbmem_console_size + sizeof(*cbmem_console),
 				 MEMREMAP_WB);
 	memunmap(tmp_cbmc);
 
-	if (!cbmem_console)
-		return -ENOMEM;
+	if (IS_ERR(cbmem_console))
+		return PTR_ERR(cbmem_console);
 
 	memconsole_setup(memconsole_coreboot_read);
 
@@ -102,9 +102,6 @@ static int memconsole_remove(struct coreboot_device *dev)
 {
 	memconsole_exit();
 
-	if (cbmem_console)
-		memunmap(cbmem_console);
-
 	return 0;
 }
 

base-commit: e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd
prerequisite-patch-id: b7c2a1e21fb108364f0e8cfaf1970cbc7903c750
-- 
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