kern/170267: IXGBE_LE32_TO_CPUS is probably an unintentional no-op

[Rich Lowe]

>Number:         170267
>Category:       kern
>Synopsis:       IXGBE_LE32_TO_CPUS is probably an unintentional no-op
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jul 30 04:10:10 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Rich Lowe
>Release:        CURRENT
>Organization:
>Environment:
>Description:
Fixing a bug in another system, using an ixgbe driver derived from yours, I've happened upon the fact that IXGBE_LE32_TO_CPUS appears to be a no-op.

On FreeBSD, it's defined to be le32dec(), which is a pure function, however the uses in ixgbe_common.c are as if it were side-effecting its argument:

  3964          /* Pull in the rest of the buffer (bi is where we left off)*/
  3965          for (; bi <= dword_len; bi++) {
  3966                  buffer[bi] = IXGBE_READ_REG_ARRAY(hw, IXGBE_FLEX_MNG, bi);
  3967                  IXGBE_LE32_TO_CPUS(&buffer[bi]);
  3968          }
>How-To-Repeat:
Read through ixgbe_common.c and ixgbe_osdep.h.  I'm unsure if this causes practical problems (I don't have a big-endian system with this board).
>Fix:
Guessing suggests that:
    buffer[bi] = IXGBE_LE32_TO_CPUS(buffer[bi]);

(there are two instances).

Is what was intended.

>Release-Note:
>Audit-Trail:
>Unformatted: