1. 16 Sep, 2020 1 commit
    • Vaibhav Jain's avatar
      powerpc/papr_scm: Fix warning triggered by perf_stats_show() · ca78ef2f
      Vaibhav Jain authored
      A warning is reported by the kernel in case perf_stats_show() returns
      an error code. The warning is of the form below:
      
       papr_scm ibm,persistent-memory:ibm,pmemory@44100001:
       	  Failed to query performance stats, Err:-10
       dev_attr_show: perf_stats_show+0x0/0x1c0 [papr_scm] returned bad count
       fill_read_buffer: dev_attr_show+0x0/0xb0 returned bad count
      
      On investigation it looks like that the compiler is silently
      truncating the return value of drc_pmem_query_stats() from 'long' to
      'int', since the variable used to store the return code 'rc' is an
      'int'. This truncated value is then returned back as a 'ssize_t' back
      from perf_stats_show() to 'dev_attr_show()' which thinks of it as a
      large unsigned number and triggers this warning..
      
      To fix this we update the type of variable 'rc' from 'int' to
      'ssize_t' that prevents the compiler from truncating the return value
      of drc_pmem_query_stats() and returning correct signed value back from
      perf_stats_show().
      
      Fixes: 2d02bf83 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP")
      Signed-off-by: default avatarVaibhav Jain <vaibhav@linux.ibm.com>
      Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20200912081451.66225-1-vaibhav@linux.ibm.com
      ca78ef2f
  2. 15 Sep, 2020 39 commits