platform/x86: thinkpad_acpi: Switch to memdup_user_nul() helper

Use memdup_user_nul() helper instead of open-coding to simplify the code.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230810122012.2110410-1-ruanjinjie@huawei.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 25cc86a..34b8b3f 100644 (file)
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -913,16 +913,9 @@ static ssize_t dispatch_proc_write(struct file *file,
        if (count > PAGE_SIZE - 1)
                return -EINVAL;
 
-       kernbuf = kmalloc(count + 1, GFP_KERNEL);
-       if (!kernbuf)
-               return -ENOMEM;
-
-       if (copy_from_user(kernbuf, userbuf, count)) {
-               kfree(kernbuf);
-               return -EFAULT;
-       }
-
-       kernbuf[count] = 0;
+       kernbuf = memdup_user_nul(userbuf, count);
+       if (IS_ERR(kernbuf))
+               return PTR_ERR(kernbuf);
        ret = ibm->write(kernbuf);
        if (ret == 0)
                ret = count;