Commit f56cb9da authored Dec 16, 2014 by Chris Rorvick Committed by Greg Kroah-Hartman Jan 17, 2015

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>

parent 965bd8b9

drivers/staging/lustre/lustre/obdclass/lprocfs_status.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -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);