Re: [HPDD-discuss] [PATCH] drivers: staging: lustre: Use mult if units not specified
On 2014/12/16, 2:41 AM, "Dan Carpenter" <dan.carpenter(a)oracle.com> wrote:
On Mon, Dec 15, 2014 at 11:41:49PM -0600, Chris Rorvick wrote:
> Units can be passed to lprocfs_write_frac_u64_helper() via a suffix
> (e.g., "...K", "...M", etc.) tacked onto the value. A comment
states
> that "specified units override the multiplier," though the multiplier is
> overridden regardless. Update the conditional logic so that it only
> applies when units are specified.
>
That introduces a bug. We need to take the initial '-' into
consideration. Just remove the condition. Also remove the "mult"
parameter since that is always 1.
bool negative = false;
...
if (*pbuf == '-') {
negative = true;
pbuf++;
}
...
mult = negative ? -units : units;
Sorry, that isn't right. Chris' patch is actually doing the right thing
to check for units > 1. The proposed change above discards "mult"
entirely, which breaks the users of this function that are not in this
file (e.g. osc_cached_mb_seq_write() or ll_max_cached_mb_seq_write())
that have tunables in units of MB by default, but can also use parameters
with units like "4.5G" for convenience.
Cheers, Andreas
--
Andreas Dilger
Lustre Software Architect
Intel High Performance Data Division