From f4533a2ceca52c443ddebec01eeaa35d51c39c1b Mon Sep 17 00:00:00 2001
From: John Reiser <jreiser-L8/tzxVKHrlWk0Htik3J/w@public.gmane.org>
Date: Tue, 13 Sep 2011 17:41:43 -0700
Subject: [PATCH 1/3] Parallelize block_module_filter

---
 modules.d/90kernel-modules/module-setup.sh |   22 ++++++++++++++++------
 1 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/modules.d/90kernel-modules/module-setup.sh b/modules.d/90kernel-modules/module-setup.sh
index 9fc4248..09bd87e 100755
--- a/modules.d/90kernel-modules/module-setup.sh
+++ b/modules.d/90kernel-modules/module-setup.sh
@@ -11,12 +11,22 @@ installkernel() {
         }
         block_module_filter() {
             local _blockfuncs='ahci_init_controller|ata_scsi_ioctl|scsi_add_host|blk_init_queue|register_mtd_blktrans|scsi_esp_register|register_virtio_device'
-            local _f
-            while read _f; do case "$_f" in
-                *.ko)    [[ $(<         $_f) =~ $_blockfuncs ]] && echo "$_f" ;;
-                *.ko.gz) [[ $(gzip -dc <$_f) =~ $_blockfuncs ]] && echo "$_f" ;;
-                esac
-            done
+            function bmf1() {
+                local _f
+                while read _f; do case "$_f" in
+                    *.ko)    [[ $(<         $_f) =~ $_blockfuncs ]] && echo "$_f" ;;
+                    *.ko.gz) [[ $(gzip -dc <$_f) =~ $_blockfuncs ]] && echo "$_f" ;;
+                    esac
+                done
+            }
+            # Use two parallel streams to filter alternating modules.
+            local merge side2
+            ( ( local _f1 _f2
+                while  read _f1; do   echo "$_f1"
+                    if read _f2; then echo "$_f2" 1>&${side2}; fi
+                done \
+                | bmf1     1>&${merge}    ) {side2}>&1 \
+                | bmf1  )      {merge}>&1
         }
         hostonly='' instmods sr_mod sd_mod scsi_dh scsi_dh_rdac scsi_dh_emc
         hostonly='' instmods pcmcia firewire-ohci
-- 
1.7.6