[PATCH] drivers: pnp: proc.c: Handle errors while attaching devices

Anupama K Patil
2021-04-24T19:43:17Z

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isapnp_proc_init() does not look at the return value from
isapnp_proc_attach_device(). Check for this return value in
isapnp_proc_detach_device().

Cleanup in isapnp_proc_detach_device and
isapnp_proc_detach_bus() for cleanup.

Changed sprintf() to the kernel-space function scnprintf() as it returns
the actual number of bytes written.

Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
save memory.

Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Co-developed-by: B K Karthik <bkkarthik@pesu.pes.edu>
Signed-off-by: B K Karthik <bkkarthik@pesu.pes.edu>
Signed-off-by: Anupama K Patil <anupamakpatil123@gmail.com>
---
drivers/pnp/isapnp/proc.c | 40 +++++++++++++++++++++++++++++----------
1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
index 785a796430fa..46ebc24175b7 100644
--- a/drivers/pnp/isapnp/proc.c
+++ b/drivers/pnp/isapnp/proc.c
@@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
.proc_read = isapnp_proc_bus_read,
};

+static int isapnp_proc_detach_device(struct pnp_dev *dev)
+{
+ proc_remove(dev->procent);
+ dev->procent = NULL;
+ return 0;
+}
+
+static int isapnp_proc_detach_bus(struct pnp_card *bus)
+{
+ proc_remove(bus->procdir);
+ return 0;
+}
+
static int isapnp_proc_attach_device(struct pnp_dev *dev)
{
struct pnp_card *bus = dev->card;
- struct proc_dir_entry *de, *e;
char name[16];

- if (!(de = bus->procdir)) {
- sprintf(name, "%02x", bus->number);
- de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
- if (!de)
+ if (!bus->procdir) {
+ scnprintf(name, 16, "%02x", bus->number);
+ bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
+ if (!bus->procdir)
return -ENOMEM;
}
- sprintf(name, "%02x", dev->number);
- e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
+ scnprintf(name, 16, "%02x", dev->number);
+ dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
&isapnp_proc_bus_proc_ops, dev);
- if (!e)
+ if (!dev->procent) {
+ isapnp_proc_detach_bus(bus);
return -ENOMEM;
- proc_set_size(e, 256);
+ }
+ proc_set_size(dev->procent, 256);
return 0;
}

int __init isapnp_proc_init(void)
{
struct pnp_dev *dev;
+ int dev_attach;

isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
protocol_for_each_dev(&isapnp_protocol, dev) {
- isapnp_proc_attach_device(dev);
+ dev_attach = isapnp_proc_attach_device(dev);
+ if (!dev_attach) {
+ pr_info("procfs: pnp: Unable to attach the device, not enough memory");
+ isapnp_proc_detach_device(dev);
+ return -ENOMEM;
+ }
}
return 0;
}
--
2.25.1

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