Re: [dpdk-dev] [PATCH v4] usertools/devbind: fix binding for built-in kernel drivers

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 20-Nov-20 2:22 AM, Yongxin Liu wrote:
> A driver can be loaded as a dynamic module or a built-in module.
> In commit 681a67288655 ("usertools: check if module is loaded
> before binding"), script only checks modules in /sys/module/.
> 
> However, for built-in kernel driver, it only shows up in /sys/module/,
> if it has a version or at least one parameter. So add check for
> modules in /lib/modules/$(uname -r)/modules.builtin.
> 
> Thanks for Anatoly Burakov's advice.
> 
> Signed-off-by: Yongxin Liu <yongxin.liu@windriver.com>
> ---
> 
> v4:
>   - Replace shell call with platform.uname(). Check file existence
>     before reading.
> 
> v3:
>   - Add built-in module list in loaded_modules for checking
>     instead of removing error check.
> 
> v2:
>   - fix git commit description style in commit log
>   - fix typo spelling
> 
> ---
>   usertools/dpdk-devbind.py | 19 ++++++++++++++++++-
>   1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/usertools/dpdk-devbind.py b/usertools/dpdk-devbind.py
> index 99112b7ab..06721709c 100755
> --- a/usertools/dpdk-devbind.py
> +++ b/usertools/dpdk-devbind.py
> @@ -7,6 +7,7 @@
>   import os
>   import getopt
>   import subprocess
> +import platform
>   from glob import glob
>   from os.path import exists, abspath, dirname, basename
>   from os.path import join as path_join
> @@ -181,7 +182,23 @@ def module_is_loaded(module):
>   
>       loaded_modules = sysfs_mods
>   
> -    return module in sysfs_mods
> +    # add built-in modules as loaded
> +    release = platform.uname().release
> +    filename = os.path.join("/lib/modules/", release, "modules.builtin")
> +    if os.path.exists(filename):
> +        try:
> +            f = open(filename, "r")
> +        except:
> +            print("Error: cannot open %s" % filename)
> +            return
> +
> +        builtin_mods = f.readlines()
> +
> +        for mod in builtin_mods:
> +            mod_name = os.path.splitext(os.path.basename(mod))
> +            loaded_modules.append(mod_name[0])
> +

You're not returning a value in error case, this would cause error in 
the caller of this function.

Also, i'd avoid reading the entire file into memory, instead I'd do 
something like this:

try:
     with open(filename) as f:
         loaded_modules += [os.path.splitext(os.path.basename(mod)[0]
                            for mod in f]
except IOError:
     print("Warning: cannot read list of built-in kernel modules")

# continue with regular code

This will be faster, more and readable as well :)

> +    return module in loaded_modules
>   
>   
>   def check_modules():
> 


-- 
Thanks,
Anatoly