Re: [PATCH v6 5/8] fs/resctrl: Add user interface to enable/disable io_alloc feature

[kernel test robot <lkp@intel.com>]

Hi Babu,

kernel test robot noticed the following build warnings:

[auto build test WARNING on brauner-vfs/vfs.all]
[also build test WARNING on linus/master v6.16-rc1 next-20250612]
[cannot apply to tip/x86/core aegl/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Babu-Moger/x86-cpufeatures-Add-support-for-L3-Smart-Data-Cache-Injection-Allocation-Enforcement/20250612-053050
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link:    https://lore.kernel.org/r/b3d8e2ccd23b295f3735fc9f5420458cfc18a896.1749677012.git.babu.moger%40amd.com
patch subject: [PATCH v6 5/8] fs/resctrl: Add user interface to enable/disable io_alloc feature
config: x86_64-randconfig-r071-20250612 (https://download.01.org/0day-ci/archive/20250613/202506130912.Uwt49HTq-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506130912.Uwt49HTq-lkp@intel.com/

smatch warnings:
fs/resctrl/rdtgroup.c:1961 resctrl_io_alloc_write() warn: unsigned 'io_alloc_closid' is never less than zero.
fs/resctrl/rdtgroup.c:1961 resctrl_io_alloc_write() warn: error code type promoted to positive: 'io_alloc_closid'

vim +/io_alloc_closid +1961 fs/resctrl/rdtgroup.c

  1934	
  1935	static ssize_t resctrl_io_alloc_write(struct kernfs_open_file *of, char *buf,
  1936					      size_t nbytes, loff_t off)
  1937	{
  1938		struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
  1939		struct rdt_resource *r = s->res;
  1940		char const *grp_name;
  1941		u32 io_alloc_closid;
  1942		bool enable;
  1943		int ret;
  1944	
  1945		ret = kstrtobool(buf, &enable);
  1946		if (ret)
  1947			return ret;
  1948	
  1949		cpus_read_lock();
  1950		mutex_lock(&rdtgroup_mutex);
  1951	
  1952		rdt_last_cmd_clear();
  1953	
  1954		if (!r->cache.io_alloc_capable) {
  1955			rdt_last_cmd_puts("io_alloc feature is not supported on the resource\n");
  1956			ret = -ENODEV;
  1957			goto out_io_alloc;
  1958		}
  1959	
  1960		io_alloc_closid = resctrl_io_alloc_closid_get(r);
> 1961		if (io_alloc_closid < 0) {
  1962			rdt_last_cmd_puts("Max CLOSID to support io_alloc is not available\n");
  1963			ret = -EINVAL;
  1964			goto out_io_alloc;
  1965		}
  1966	
  1967		if (resctrl_arch_get_io_alloc_enabled(r) != enable) {
  1968			if (enable) {
  1969				ret = resctrl_io_alloc_closid_alloc(io_alloc_closid);
  1970				if (ret < 0) {
  1971					grp_name = rdtgroup_name_by_closid(io_alloc_closid);
  1972					rdt_last_cmd_printf("CLOSID for io_alloc is used by %s group\n",
  1973							    grp_name ? grp_name : "another");
  1974					ret = -EINVAL;
  1975					goto out_io_alloc;
  1976				}
  1977	
  1978				ret = resctrl_io_alloc_init_cat(r, resctrl_schema_io_alloc(s),
  1979								io_alloc_closid);
  1980				if (ret) {
  1981					rdt_last_cmd_puts("Failed to initialize io_alloc allocations\n");
  1982					resctrl_io_alloc_closid_free(io_alloc_closid);
  1983					goto out_io_alloc;
  1984				}
  1985	
  1986			} else {
  1987				resctrl_io_alloc_closid_free(io_alloc_closid);
  1988			}
  1989	
  1990			ret = resctrl_arch_io_alloc_enable(r, enable);
  1991		}
  1992	
  1993	out_io_alloc:
  1994		mutex_unlock(&rdtgroup_mutex);
  1995		cpus_read_unlock();
  1996	
  1997		return ret ?: nbytes;
  1998	}
  1999	

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