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misc: c2port: Calculate bin_attribute size through group callback

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Modifying the size of the global bin_attribute instance can be racy.
Instead use the new .bin_size callback to do so safely.

For this to work move the initialization of c2dev->ops before the call
to device_create() as the size callback will need access to it.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20241221-sysfs-const-bin_attr-misc-drivers-v2-4-ba5e79fe8771@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Weißschuh
2024-12-21 15:48:10 +01:00
committed by Greg Kroah-Hartman
parent c3b8c358c4
commit 85aa1342d7
1 changed files with 14 additions and 3 deletions
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17
drivers/misc/c2port/core.c
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@@ -874,9 +874,22 @@ static struct bin_attribute *c2port_bin_attrs[] = {
NULL,
};
static size_t c2port_bin_attr_size(struct kobject *kobj,
const struct bin_attribute *attr,
int i)
{
struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
if (attr == &bin_attr_flash_data)
return c2dev->ops->blocks_num * c2dev->ops->block_size;
return attr->size;
}
static const struct attribute_group c2port_group = {
.attrs = c2port_attrs,
.bin_attrs = c2port_bin_attrs,
.bin_size = c2port_bin_attr_size,
};
static const struct attribute_group *c2port_groups[] = {
@@ -912,8 +925,7 @@ struct c2port_device *c2port_device_register(char *name,
if (ret < 0)
goto error_idr_alloc;
c2dev->id = ret;
bin_attr_flash_data.size = ops->blocks_num * ops->block_size;
c2dev->ops = ops;
c2dev->dev = device_create(c2port_class, NULL, 0, c2dev,
"c2port%d", c2dev->id);
@@ -924,7 +936,6 @@ struct c2port_device *c2port_device_register(char *name,
dev_set_drvdata(c2dev->dev, c2dev);
strscpy(c2dev->name, name, sizeof(c2dev->name));
c2dev->ops = ops;
mutex_init(&c2dev->mutex);
/* By default C2 port access is off */