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IB/ipath: Better comment for rmb() in ipath_intr()

An internal code review found the comment here lacking -- update it with 
more specifics of how and why the rmb() is there.

Signed-off-by: Arthur Jones <arthur.jones@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Arthur Jones 2007-10-17 18:18:29 -07:00 committed by Roland Dreier
parent 6276980138
commit 2f01a70011
1 changed files with 9 additions and 1 deletions

View File

@ -954,7 +954,15 @@ static void handle_urcv(struct ipath_devdata *dd, u32 istat)
int i;
int rcvdint = 0;
/* test_bit below needs this... */
/*
* test_and_clear_bit(IPATH_PORT_WAITING_RCV) and
* test_and_clear_bit(IPATH_PORT_WAITING_URG) below
* would both like timely updates of the bits so that
* we don't pass them by unnecessarily. the rmb()
* here ensures that we see them promptly -- the
* corresponding wmb()'s are in ipath_poll_urgent()
* and ipath_poll_next()...
*/
rmb();
portr = ((istat >> INFINIPATH_I_RCVAVAIL_SHIFT) &
dd->ipath_i_rcvavail_mask)