ipmi:ssif: compare block number correctly for multi-part return messages

commit 55be8658c7e2feb11a5b5b33ee031791dbd23a69 upstream.

According to ipmi spec, block number is a number that is incremented,
starting with 0, for each new block of message data returned using the
middle transaction.

Here, the 'blocknum' is data[0] which always starts from zero(0) and
'ssif_info->multi_pos' starts from 1.
So, we need to add +1 to blocknum while comparing with multi_pos.

Fixes: 7d6380cd40f79 ("ipmi:ssif: Fix handling of multi-part return messages").
Reported-by: Kiran Kolukuluru <kirank@ami.com>
Signed-off-by: Kamlakant Patel <kamlakantp@marvell.com>
Message-Id: <1556106615-18722-1-git-send-email-kamlakantp@marvell.com>
[Also added a debug log if the block numbers don't match.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index b7a1ae2afaeac7435410f6c100d7e9941f2cb486..05010b1d04e9f0abfb693f4e9aa8c3bc88e6a266 100644 (file)
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -690,12 +690,16 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
                        /* End of read */
                        len = ssif_info->multi_len;
                        data = ssif_info->data;
-               } else if (blocknum != ssif_info->multi_pos) {
+               } else if (blocknum + 1 != ssif_info->multi_pos) {
                        /*
                         * Out of sequence block, just abort.  Block
                         * numbers start at zero for the second block,
                         * but multi_pos starts at one, so the +1.
                         */
+                       if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
+                               dev_dbg(&ssif_info->client->dev,
+                                       "Received message out of sequence, expected %u, got %u\n",
+                                       ssif_info->multi_pos - 1, blocknum);
                        result = -EIO;
                } else {
                        ssif_inc_stat(ssif_info, received_message_parts);