[PATCH] virtio-blk: fixup coccinelle warnings

[PATCH] virtio-blk: fixup coccinelle warnings

[cgel.zte]

From: Ye Guojin <ye.guojin@zte.com.cn>

coccicheck complains about the use of snprintf() in sysfs show
functions:
WARNING  use scnprintf or sprintf

Use sysfs_emit instead of scnprintf or sprintf makes more sense.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn>
---
 drivers/block/virtio_blk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 303caf2d17d0..8a71b2f9f4b7 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -624,7 +624,7 @@ cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
 	u8 writeback = virtblk_get_cache_mode(vblk->vdev);
 
 	BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
-	return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
+	return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
 }
 
 static DEVICE_ATTR_RW(cache_type);
-- 
2.25.1

Re: [PATCH] virtio-blk: fixup coccinelle warnings

[Joe Perches]

On Thu, 2021-10-21 at 06:51 +0000, cgel.zte@gmail.com wrote:
> From: Ye Guojin <ye.guojin@zte.com.cn>
> 
> coccicheck complains about the use of snprintf() in sysfs show
> functions:
> WARNING  use scnprintf or sprintf
> 
> Use sysfs_emit instead of scnprintf or sprintf makes more sense.
[]
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
[]
> @@ -624,7 +624,7 @@ cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
> -	return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
> +	return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);

Perhaps scripts/coccinelle/api/device_attr_show.cocci should be updated
to be more like the script used in commit 1c7fd72687d6

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	sprintf(buf,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	snprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	scnprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	strcpy(buf, chr);
+	sysfs_emit(buf, chr);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	sprintf(buf,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	snprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	scnprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
-	len += scnprintf(buf + len, PAGE_SIZE - len,
+	len += sysfs_emit_at(buf, len,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	...
-	strcpy(buf, chr);
-	return strlen(buf);
+	return sysfs_emit(buf, chr);
}

Re: [PATCH] virtio-blk: fixup coccinelle warnings

[Stefan Hajnoczi]

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On Thu, Oct 21, 2021 at 12:08:23AM -0700, Joe Perches wrote:
> On Thu, 2021-10-21 at 06:51 +0000, cgel.zte@gmail.com wrote:
> > From: Ye Guojin <ye.guojin@zte.com.cn>
> > 
> > coccicheck complains about the use of snprintf() in sysfs show
> > functions:
> > WARNING  use scnprintf or sprintf
> > 
> > Use sysfs_emit instead of scnprintf or sprintf makes more sense.
> []
> > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> []
> > @@ -624,7 +624,7 @@ cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
> > -	return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
> > +	return sysfs_emit(buf, "%s\n", virtblk_cache_types[writeback]);
> 
> Perhaps scripts/coccinelle/api/device_attr_show.cocci should be updated
> to be more like the script used in commit 1c7fd72687d6

This won't catch the case covered by the patch because it's
"snprintf(buf, 40" instead of "snprintf(buf, PAGE_SIZE", although
any size that's not PAGE_SIZE needs to be reviewed carefully in case the
intent of the statement is to truncate the output.

Stefan

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Re: [PATCH] virtio-blk: fixup coccinelle warnings

[Stefan Hajnoczi]

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On Thu, Oct 21, 2021 at 06:51:11AM +0000, cgel.zte@gmail.com wrote:
> From: Ye Guojin <ye.guojin@zte.com.cn>
> 
> coccicheck complains about the use of snprintf() in sysfs show
> functions:
> WARNING  use scnprintf or sprintf
> 
> Use sysfs_emit instead of scnprintf or sprintf makes more sense.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn>
> ---
>  drivers/block/virtio_blk.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [PATCH] virtio-blk: fixup coccinelle warnings

[Stefano Garzarella]

On Thu, Oct 21, 2021 at 06:51:11AM +0000, cgel.zte@gmail.com wrote:
>From: Ye Guojin <ye.guojin@zte.com.cn>
>
>coccicheck complains about the use of snprintf() in sysfs show
>functions:
>WARNING  use scnprintf or sprintf
>
>Use sysfs_emit instead of scnprintf or sprintf makes more sense.
>
>Reported-by: Zeal Robot <zealci@zte.com.cn>
>Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn>
>---
> drivers/block/virtio_blk.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>