On 01.12.2020 09:21, Juergen Gross wrote:
> @@ -1003,12 +1006,131 @@ static struct notifier_block cpu_nfb = {
> .notifier_call = cpu_callback
> };
>
> +#ifdef CONFIG_HYPFS
> +static const struct hypfs_entry *cpupool_pooldir_enter(
> + const struct hypfs_entry *entry);
> +
> +static struct hypfs_funcs cpupool_pooldir_funcs = {
Yet one more const missing?
> + .enter = cpupool_pooldir_enter,
> + .exit = hypfs_node_exit,
> + .read = hypfs_read_dir,
> + .write = hypfs_write_deny,
> + .getsize = hypfs_getsize,
> + .findentry = hypfs_dir_findentry,
> +};
> +
> +static HYPFS_VARDIR_INIT(cpupool_pooldir, "%u", &cpupool_pooldir_funcs);
> +
> +static const struct hypfs_entry *cpupool_pooldir_enter(
> + const struct hypfs_entry *entry)
> +{
> + return &cpupool_pooldir.e;
> +}
> +
> +static int cpupool_dir_read(const struct hypfs_entry *entry,
> + XEN_GUEST_HANDLE_PARAM(void) uaddr)
> +{
> + int ret = 0;
> + const struct cpupool *c;
> + unsigned int size = 0;
> +
> + list_for_each_entry(c, &cpupool_list, list)
> + {
> + size += hypfs_dynid_entry_size(entry, c->cpupool_id);
Why do you maintain size here? I can't spot any use.
With this dropped the function then no longer depends on its
"entry" parameter, which makes me wonder ...
> + ret = hypfs_read_dyndir_id_entry(&cpupool_pooldir, c->cpupool_id,
> + list_is_last(&c->list,
> &cpupool_list),
> + &uaddr);
> + if ( ret )
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static unsigned int cpupool_dir_getsize(const struct hypfs_entry *entry)
> +{
> + const struct cpupool *c;
> + unsigned int size = 0;
> +
> + list_for_each_entry(c, &cpupool_list, list)
> + size += hypfs_dynid_entry_size(entry, c->cpupool_id);
... why this one does. To be certain their results are consistent
with one another, I think both should produce their results from
the same data.
> + return size;
> +}
> +
> +static const struct hypfs_entry *cpupool_dir_enter(
> + const struct hypfs_entry *entry)
> +{
> + struct hypfs_dyndir_id *data;
> +
> + data = hypfs_alloc_dyndata(sizeof(*data));
I generally like the added type safety of the macro wrappers
around _xmalloc(). I wonder if it wouldn't be a good idea to have
such here as well, to avoid random mistakes like
data = hypfs_alloc_dyndata(sizeof(data));
However I further notice that the struct allocated isn't cpupool
specific at all. It would seem to me that such an allocation
therefore doesn't belong here. Therefore I wonder whether ...
> + if ( !data )
> + return ERR_PTR(-ENOMEM);
> + data->id = CPUPOOLID_NONE;
> +
> + spin_lock(&cpupool_lock);
... these two properties (initial ID and lock) shouldn't e.g. be
communicated via the template, allowing the enter/exit hooks to
become generic for all ID templates.
Yet in turn I notice that the "id" field only ever gets set, both
in patch 14 and here. But yes, I've now spotted the consumers in
patch 16.
> + return entry;
> +}
> +
> +static void cpupool_dir_exit(const struct hypfs_entry *entry)
> +{
> + spin_unlock(&cpupool_lock);
> +
> + hypfs_free_dyndata();
> +}
> +
> +static struct hypfs_entry *cpupool_dir_findentry(
> + const struct hypfs_entry_dir *dir, const char *name, unsigned int
> name_len)
> +{
> + unsigned long id;
> + const char *end;
> + const struct cpupool *cpupool;
> +
> + id = simple_strtoul(name, &end, 10);
> + if ( end != name + name_len )
> + return ERR_PTR(-ENOENT);
> +
> + cpupool = __cpupool_find_by_id(id, true);
Silent truncation from unsigned long to unsigned int?
> + if ( !cpupool )
> + return ERR_PTR(-ENOENT);
> +
> + return hypfs_gen_dyndir_entry_id(&cpupool_pooldir, id);
> +}
> +
> +static struct hypfs_funcs cpupool_dir_funcs = {
Yet another missing const?
> + .enter = cpupool_dir_enter,
> + .exit = cpupool_dir_exit,
> + .read = cpupool_dir_read,
> + .write = hypfs_write_deny,
> + .getsize = cpupool_dir_getsize,
> + .findentry = cpupool_dir_findentry,
> +};
> +
> +static HYPFS_VARDIR_INIT(cpupool_dir, "cpupool", &cpupool_dir_funcs);
Why VARDIR? This isn't a template, is it? Or does VARDIR really
serve multiple purposes?
> +static void cpupool_hypfs_init(void)
> +{
> + hypfs_add_dir(&hypfs_root, &cpupool_dir, true);
> + hypfs_add_dyndir(&cpupool_dir, &cpupool_pooldir);
> +}
> +#else
> +
> +static void cpupool_hypfs_init(void)
> +{
> +}
> +#endif
I think you want to be consistent with the use of blank lines next
to #if / #else / #endif. In cases when they enclose multiple entities,
I think it's generally better to have intervening blank lines
everywhere. I also think in such cases commenting #else and #endif is
helpful. But you're the maintainer of this code ...
Jan
