Re: [PATCH v6 8/8] fs/resctrl: Introduce interface to modify io_alloc Capacity Bit Masks

[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/6f8158ba0eebf41c9ec59e82dcdc28d4d3151c3b.1749677012.git.babu.moger%40amd.com
patch subject: [PATCH v6 8/8] fs/resctrl: Introduce interface to modify io_alloc Capacity Bit Masks
config: x86_64-randconfig-r071-20250612 (https://download.01.org/0day-ci/archive/20250613/202506131403.MWHHLsxB-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/202506131403.MWHHLsxB-lkp@intel.com/

New smatch warnings:
fs/resctrl/rdtgroup.c:2105 resctrl_io_alloc_cbm_write() warn: unsigned 'io_alloc_closid' is never less than zero.
fs/resctrl/rdtgroup.c:2105 resctrl_io_alloc_cbm_write() warn: error code type promoted to positive: 'io_alloc_closid'

Old 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'
fs/resctrl/rdtgroup.c:2026 resctrl_io_alloc_cbm_show() warn: unsigned 'io_alloc_closid' is never less than zero.
fs/resctrl/rdtgroup.c:2026 resctrl_io_alloc_cbm_show() warn: error code type promoted to positive: 'io_alloc_closid'

vim +/io_alloc_closid +2105 fs/resctrl/rdtgroup.c

  2072	
  2073	static ssize_t resctrl_io_alloc_cbm_write(struct kernfs_open_file *of,
  2074						  char *buf, size_t nbytes, loff_t off)
  2075	{
  2076		struct resctrl_schema *s = rdt_kn_parent_priv(of->kn);
  2077		struct rdt_resource *r = s->res;
  2078		u32 io_alloc_closid;
  2079		int ret = 0;
  2080	
  2081		/* Valid input requires a trailing newline */
  2082		if (nbytes == 0 || buf[nbytes - 1] != '\n')
  2083			return -EINVAL;
  2084	
  2085		buf[nbytes - 1] = '\0';
  2086	
  2087		if (!r->cache.io_alloc_capable) {
  2088			rdt_last_cmd_puts("io_alloc feature is not supported on the resource\n");
  2089			return -EINVAL;
  2090		}
  2091	
  2092		cpus_read_lock();
  2093		mutex_lock(&rdtgroup_mutex);
  2094	
  2095		rdt_last_cmd_clear();
  2096		rdt_staged_configs_clear();
  2097	
  2098		if (!resctrl_arch_get_io_alloc_enabled(r)) {
  2099			rdt_last_cmd_puts("io_alloc feature is not enabled\n");
  2100			ret = -EINVAL;
  2101			goto cbm_write_out;
  2102		}
  2103	
  2104		io_alloc_closid = resctrl_io_alloc_closid_get(r);
> 2105		if (io_alloc_closid < 0) {
  2106			rdt_last_cmd_puts("Max CLOSID to support io_alloc is not available\n");
  2107			ret = -EINVAL;
  2108			goto cbm_write_out;
  2109		}
  2110	
  2111		ret = resctrl_io_alloc_parse_line(buf, r, resctrl_schema_io_alloc(s),
  2112						  io_alloc_closid);
  2113		if (ret)
  2114			goto cbm_write_out;
  2115	
  2116		ret = resctrl_arch_update_domains(r, io_alloc_closid);
  2117	
  2118	cbm_write_out:
  2119		rdt_staged_configs_clear();
  2120		mutex_unlock(&rdtgroup_mutex);
  2121		cpus_read_unlock();
  2122	
  2123		return ret ?: nbytes;
  2124	}
  2125	

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