On Fri, 2015-10-30 at 01:32 +0200, Andy Shevchenko wrote: > On Fri, Oct 30, 2015 at 1:00 AM, James Bottomley <jbottom...@odin.com> wrote: > > On Thu, 2015-10-29 at 17:30 +0100, Vitaly Kuznetsov wrote: > >> Division by zero happens if blk_size=0 is supplied to string_get_size(). > >> Add WARN_ON() and set size to 0 to report '0 B'. > >> > >> Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> > >> --- > >> lib/string_helpers.c | 5 +++++ > >> 1 file changed, 5 insertions(+) > >> > >> diff --git a/lib/string_helpers.c b/lib/string_helpers.c > >> index f6c27dc..ff3575b 100644 > >> --- a/lib/string_helpers.c > >> +++ b/lib/string_helpers.c > >> @@ -50,6 +50,11 @@ void string_get_size(u64 size, u32 blk_size, const enum > >> string_size_units units, > >> > >> tmp[0] = '\0'; > >> i = 0; > >> + > >> + /* Calling string_get_size() with blk_size=0 is wrong! */ > >> + if (WARN_ON(!blk_size)) > > > > Get rid of the WARN_ON; it's the standard thing to do for a partially > > connected device. Seeing zero is standard in a whole variety of > > situations. SCSI shims the zero but most other drivers don't. > > For *block* size? It will crash the kernel. I've checked, it wasn't > changed from the beginning (b9f28d863594).
The standard signal for a drive error in capacity is zero size and zero block size. We have to take that case as standard without emitting scary warnings. James