queue-4.4/ipmi-ssif-compare-block-number-correctly-for-multi-part-return-messages.patch

   1 From 55be8658c7e2feb11a5b5b33ee031791dbd23a69 Mon Sep 17 00:00:00 2001
   2 From: Kamlakant Patel <kamlakantp@marvell.com>
   3 Date: Wed, 24 Apr 2019 11:50:43 +0000
   4 Subject: ipmi:ssif: compare block number correctly for multi-part return messages
   5
   6 From: Kamlakant Patel <kamlakantp@marvell.com>
   7
   8 commit 55be8658c7e2feb11a5b5b33ee031791dbd23a69 upstream.
   9
  10 According to ipmi spec, block number is a number that is incremented,
  11 starting with 0, for each new block of message data returned using the
  12 middle transaction.
  13
  14 Here, the 'blocknum' is data[0] which always starts from zero(0) and
  15 'ssif_info->multi_pos' starts from 1.
  16 So, we need to add +1 to blocknum while comparing with multi_pos.
  17
  18 Fixes: 7d6380cd40f79 ("ipmi:ssif: Fix handling of multi-part return messages").
  19 Reported-by: Kiran Kolukuluru <kirank@ami.com>
  20 Signed-off-by: Kamlakant Patel <kamlakantp@marvell.com>
  21 Message-Id: <1556106615-18722-1-git-send-email-kamlakantp@marvell.com>
  22 [Also added a debug log if the block numbers don't match.]
  23 Signed-off-by: Corey Minyard <cminyard@mvista.com>
  24 Cc: stable@vger.kernel.org # 4.4
  25 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  26
  27 ---
  28  drivers/char/ipmi/ipmi_ssif.c |    6 +++++-
  29  1 file changed, 5 insertions(+), 1 deletion(-)
  30
  31 --- a/drivers/char/ipmi/ipmi_ssif.c
  32 +++ b/drivers/char/ipmi/ipmi_ssif.c
  33 @@ -695,12 +695,16 @@ static void msg_done_handler(struct ssif
  34                         /* End of read */
  35                         len = ssif_info->multi_len;
  36                         data = ssif_info->data;
  37 -               } else if (blocknum != ssif_info->multi_pos) {
  38 +               } else if (blocknum + 1 != ssif_info->multi_pos) {
  39                         /*
  40                          * Out of sequence block, just abort.  Block
  41                          * numbers start at zero for the second block,
  42                          * but multi_pos starts at one, so the +1.
  43                          */
  44 +                       if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
  45 +                               dev_dbg(&ssif_info->client->dev,
  46 +                                       "Received message out of sequence, expected %u, got %u\n",
  47 +                                       ssif_info->multi_pos - 1, blocknum);
  48                         result = -EIO;
  49                 } else {
  50                         ssif_inc_stat(ssif_info, received_message_parts);