[PATCH v4] Hardware iSCSI boot disk support

[WANG Chao]

In 1st kernel, the iscsi device could be both software or hardware
based. But we only use software iscsi in 2nd kernel. This is fine for
software iscsi as it's consistent with 1st kernel. However kdump
bringing up hardware iscsi in software mode could lead conflicts with
dracut bringing up logic, depending on the configuration.

If boot disk is hardware iscsi, we should still use hardware iscsi in
2nd kernel. In this case, dracut will bring up the device like it does
for normal boot. kdump don't need to do extra work to configure software
iscsi.

[Quoting from Bao]

hw iscsi --> rd.iscsi.firmware=1 need be specified in
            cmdline of 1st kernel
          /
HBA (bios)
          \ ip=ibft  need be specified in cmdline. But if no
            rd.iscsi.firmware=1, only bring up that NIC

For above 2 cases, we did nothing in kdump shell since it's enough to inherit
the kernel cmdline of 1st kernel. And both of them are only concerned
with the case which boot disk is dump target.

HBA -> /dev/sdx

For above case, the hw firmare is very smart and can take care of
anything. When system bootup if will appear automatically. This works
for kdump kernel too.

[End of quoting]

The other iscsi cases have very complicated combinations, which I've
tried to cover but fail. Since they're the cases not requested by
customers, I think we can handle them case by case in the future. Anyway
we've been stucking at hardware iscsi for a while. If this kind of
partial fix works for most of the use case, I think we can add this
first.

Signed-off-by: WANG Chao 
---
 dracut-module-setup.sh | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index ff7a088..3c96076 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -415,7 +415,11 @@ kdump_get_iscsi_initiator() {
     return 1
 }

-# No ibft handling yet.
+# Figure out if the iscsi session is based on iBFT or firmware
+kdump_handle_hw_iscsi() {
+    [ "$(kdump_iscsi_get_rec_val $1 "node.discovery_type")" = fw ]
+}
+
 kdump_setup_iscsi_device() {
     local path=$1
     local tgt_name; local tgt_ipaddr;
@@ -438,6 +442,10 @@ kdump_setup_iscsi_device() {
         return 1
     fi

+    if kdump_handle_hw_iscsi ${path}; then
+        return 0
+    fi
+
     tgt_name=$(kdump_iscsi_get_rec_val ${path} "node.name")
     tgt_ipaddr=$(kdump_iscsi_get_rec_val ${path} "node.conn[0].address")