src/patches/suse-2.6.27.39/patches.fixes/iscsi_tcp-propogate-EAGAIN-from-sendpage-to-libiscsi

   1 From: Hannes Reinecke <hare@suse.de>
   2 Date: Tue, 18 Aug 2009 10:01:42 +0200
   3 Subject: iscsi_tcp: propogate EAGAIN from sendpage to libiscsi
   4 References: bnc#472432
   5 X-Git: 32382492eb18e8e20be382a1743d0c08469d1e84
   6
   7 The net layer might return -EAGAIN because it could not
   8 get space/mem within the sock sndtimeo or becuase the tcp/ip
   9 connection was down. For the latter we do not want to retry
  10 because the conn/session should just be shutdown and restarted.
  11 libiscsi knows the state of the session recovery so propogate
  12 this error to that layer. It will either do iscsi recovery
  13 or have us retry the operation. Right now if we have partially
  14 sent a pdu we would always retry the IO xmit slowing down
  15 recovery.
  16
  17 Backported to SLES11.
  18
  19 Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
  20 Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
  21 Signed-off-by: Hannes Reinecke <hare@suse.de>
  22 ---
  23  drivers/scsi/iscsi_tcp.c |   14 +++++++++-----
  24  1 files changed, 9 insertions(+), 5 deletions(-)
  25
  26 diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
  27 index 324e719..25094c9 100644
  28 --- a/drivers/scsi/iscsi_tcp.c
  29 +++ b/drivers/scsi/iscsi_tcp.c
  30 @@ -317,8 +317,6 @@ iscsi_tcp_xmit_segment(struct iscsi_tcp_conn *tcp_conn,
  31
  32                 if (r < 0) {
  33                         iscsi_tcp_segment_unmap(segment);
  34 -                       if (copied || r == -EAGAIN)
  35 -                               break;
  36                         return r;
  37                 }
  38                 copied += r;
  39 @@ -1150,11 +1148,17 @@ iscsi_xmit(struct iscsi_conn *conn)
  40
  41         while (1) {
  42                 rc = iscsi_tcp_xmit_segment(tcp_conn, segment);
  43 -               if (rc < 0) {
  44 +               /*
  45 +                * We may not have been able to send data because the conn
  46 +                * is getting stopped. libiscsi will know so propogate err
  47 +                * for it to do the right thing.
  48 +                */
  49 +               if (rc == -EAGAIN)
  50 +                       return rc;
  51 +               else if (rc < 0) {
  52                         rc = ISCSI_ERR_CONN_FAILED;
  53                         goto error;
  54 -               }
  55 -               if (rc == 0)
  56 +               } else if (rc == 0)
  57                         break;
  58
  59                 consumed += rc;
  60 --
  61 1.6.0.2
  62