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From: Xin LI <delphij@FreeBSD.org>
Date: Wed, 23 Nov 2011 20:01:35 +0000 (UTC)
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Subject: svn commit: r227905 - projects/head_mfi/sys/dev/mfi
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Author: delphij
Date: Wed Nov 23 20:01:35 2011
New Revision: 227905
URL: http://svn.freebsd.org/changeset/base/227905

Log:
  Apply a different approach for the timeout from Scott Long.  Instead of doing
  the (expensive) dummy read and do nothing with the result, move it to the end
  of the interrupt handler, and restart the interrupt handler if we see more
  pending job to do.

Modified:
  projects/head_mfi/sys/dev/mfi/mfi.c

Modified: projects/head_mfi/sys/dev/mfi/mfi.c
==============================================================================
--- projects/head_mfi/sys/dev/mfi/mfi.c	Wed Nov 23 19:38:32 2011	(r227904)
+++ projects/head_mfi/sys/dev/mfi/mfi.c	Wed Nov 23 20:01:35 2011	(r227905)
@@ -1230,12 +1230,7 @@ mfi_intr(void *arg)
 	if (sc->mfi_check_clear_intr(sc))
 		return;
 
-	/*
-	 * Do a dummy read to flush the interrupt ACK that we just performed,
-	 * ensuring that everything is really, truly consistent.
-	 */
-	(void)sc->mfi_read_fw_status(sc);
-
+restart:
 	pi = sc->mfi_comms->hw_pi;
 	ci = sc->mfi_comms->hw_ci;
 	mtx_lock(&sc->mfi_io_lock);
@@ -1260,6 +1255,14 @@ mfi_intr(void *arg)
 	mfi_startio(sc);
 	mtx_unlock(&sc->mfi_io_lock);
 
+	/*
+	 * Dummy read to flush the bus; this ensures that the indexes are up
+	 * to date.  Restart processing if more commands have come it.
+	 */
+	(void)sc->mfi_read_fw_status(sc);
+	if (pi != sc->mfi_comms->hw_pi)
+		goto restart;
+
 	return;
 }