Re: [PATCH v26 07/13] mm/damon: Implement a debugfs-based user space interface
From: SeongJae Park
On Tue, 30 Mar 2021 09:59:50 + SeongJae Park wrote:
> From: SeongJae Park
>
> On Tue, 30 Mar 2021 11:22:45 +0200 Greg KH wrote:
>
> > On Tue, Mar 30, 2021 at 09:05:31AM +, sj38.p...@gmail.com wrote:
> > > +static int __init __damon_dbgfs_init(void)
> > > +{
> > > + struct dentry *dbgfs_root;
> > > + const char * const file_names[] = {"monitor_on"};
> > > + const struct file_operations *fops[] = {_on_fops};
> > > + int i;
> > > +
> > > + dbgfs_root = debugfs_create_dir("damon", NULL);
> > > +
> > > + for (i = 0; i < ARRAY_SIZE(file_names); i++)
> > > + debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL,
> > > + fops[i]);
> > > + dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
> > > +
> > > + dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL);
> >
> > No error checking for memory allocation failures?
>
> Oops, I will add the check in the next spin.
>
> >
> >
> > > + dbgfs_dirs[0] = dbgfs_root;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/*
> > > + * Functions for the initialization
> > > + */
> > > +
> > > +static int __init damon_dbgfs_init(void)
> > > +{
> > > + int rc;
> > > +
> > > + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
> >
> > No error checking?
>
> Will add in the next spin.
>
> >
> > > + dbgfs_ctxs[0] = dbgfs_new_ctx();
> > > + if (!dbgfs_ctxs[0])
> > > + return -ENOMEM;
And, I found that I'm not printing the error for this failure. I guess this
might made you to to think below error message should printed inside the
callee.
I will add 'pr_err()' here and above unchecked failure case, in the next
version.
BTW, I forgot saying thank you for your review. Appreciate!
Thanks,
SeongJae Park
> > > + dbgfs_nr_ctxs = 1;
> > > +
> > > + rc = __damon_dbgfs_init();
> > > + if (rc)
> > > + pr_err("%s: dbgfs init failed\n", __func__);
> >
> > Shouldn't the error be printed out in the function that failed, not in
> > this one?
>
> I thought some other functions (in future) might want to use
> '__damon_dbgfs_init()' but siletnly handles it's failure. Therefore I made
> the
> function fails silently but returns the error code explicitly. Am I missing
> somthing?
>
>
> Thanks,
> SeongJae Park
>
> >
> > thanks,
> >
> > greg k-h
>
Re: [PATCH v26 07/13] mm/damon: Implement a debugfs-based user space interface
From: SeongJae Park
On Tue, 30 Mar 2021 11:22:45 +0200 Greg KH wrote:
> On Tue, Mar 30, 2021 at 09:05:31AM +, sj38.p...@gmail.com wrote:
> > +static int __init __damon_dbgfs_init(void)
> > +{
> > + struct dentry *dbgfs_root;
> > + const char * const file_names[] = {"monitor_on"};
> > + const struct file_operations *fops[] = {_on_fops};
> > + int i;
> > +
> > + dbgfs_root = debugfs_create_dir("damon", NULL);
> > +
> > + for (i = 0; i < ARRAY_SIZE(file_names); i++)
> > + debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL,
> > + fops[i]);
> > + dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
> > +
> > + dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL);
>
> No error checking for memory allocation failures?
Oops, I will add the check in the next spin.
>
>
> > + dbgfs_dirs[0] = dbgfs_root;
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * Functions for the initialization
> > + */
> > +
> > +static int __init damon_dbgfs_init(void)
> > +{
> > + int rc;
> > +
> > + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
>
> No error checking?
Will add in the next spin.
>
> > + dbgfs_ctxs[0] = dbgfs_new_ctx();
> > + if (!dbgfs_ctxs[0])
> > + return -ENOMEM;
> > + dbgfs_nr_ctxs = 1;
> > +
> > + rc = __damon_dbgfs_init();
> > + if (rc)
> > + pr_err("%s: dbgfs init failed\n", __func__);
>
> Shouldn't the error be printed out in the function that failed, not in
> this one?
I thought some other functions (in future) might want to use
'__damon_dbgfs_init()' but siletnly handles it's failure. Therefore I made the
function fails silently but returns the error code explicitly. Am I missing
somthing?
Thanks,
SeongJae Park
>
> thanks,
>
> greg k-h
Re: [PATCH v26 07/13] mm/damon: Implement a debugfs-based user space interface
On Tue, Mar 30, 2021 at 09:05:31AM +, sj38.p...@gmail.com wrote:
> +static int __init __damon_dbgfs_init(void)
> +{
> + struct dentry *dbgfs_root;
> + const char * const file_names[] = {"monitor_on"};
> + const struct file_operations *fops[] = {_on_fops};
> + int i;
> +
> + dbgfs_root = debugfs_create_dir("damon", NULL);
> +
> + for (i = 0; i < ARRAY_SIZE(file_names); i++)
> + debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL,
> + fops[i]);
> + dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]);
> +
> + dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL);
No error checking for memory allocation failures?
> + dbgfs_dirs[0] = dbgfs_root;
> +
> + return 0;
> +}
> +
> +/*
> + * Functions for the initialization
> + */
> +
> +static int __init damon_dbgfs_init(void)
> +{
> + int rc;
> +
> + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
No error checking?
> + dbgfs_ctxs[0] = dbgfs_new_ctx();
> + if (!dbgfs_ctxs[0])
> + return -ENOMEM;
> + dbgfs_nr_ctxs = 1;
> +
> + rc = __damon_dbgfs_init();
> + if (rc)
> + pr_err("%s: dbgfs init failed\n", __func__);
Shouldn't the error be printed out in the function that failed, not in
this one?
thanks,
greg k-h
