drivers: staging: lustre: Track sign separately

The `mult' parameter is negated if the user data begins with a '-' so
that the final value has the appropriate sign.  But `mult' is only used
if the user data does not include a "units" suffix.  In this case,
`mult' is overridden with the numeric scale conveyed by the units suffix,
but retains the sign of the original value.

Having `mult' serving double-duty works but is confusing.  Use a new
local variable to store the sign of the user data instead.  This also
fixes a pitfall of passing 0 to `mult', expecting it to be ignored when
a units suffix is specified, but having the effect of taking the
absolute value of the user-provided data.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c
index 5aada17c64507baacad3f697bb8b092dedf3fc72..9043f72c21ba1301e5248cd22adc920e7f16b9ad 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c
+++ b/drivers/staging/lustre/lustre/obdclass/lprocfs_status.c
@@ -1862,6 +1862,7 @@ int lprocfs_write_frac_u64_helper(const char *buffer, unsigned long count,
        char kernbuf[22], *end, *pbuf;
        __u64 whole, frac = 0, units;
        unsigned frac_d = 1;
+       int sign = 1;
 
        if (count > (sizeof(kernbuf) - 1))
                return -EINVAL;
@@ -1872,7 +1873,7 @@ int lprocfs_write_frac_u64_helper(const char *buffer, unsigned long count,
        kernbuf[count] = '\0';
        pbuf = kernbuf;
        if (*pbuf == '-') {
-               mult = -mult;
+               sign = -1;
                pbuf++;
        }
 
@@ -1909,11 +1910,11 @@ int lprocfs_write_frac_u64_helper(const char *buffer, unsigned long count,
        }
        /* Specified units override the multiplier */
        if (units > 1)
-               mult = mult < 0 ? -units : units;
+               mult = units;
 
        frac *= mult;
        do_div(frac, frac_d);
-       *val = whole * mult + frac;
+       *val = sign * (whole * mult + frac);
        return 0;
 }
 EXPORT_SYMBOL(lprocfs_write_frac_u64_helper);