Commit:     3c887e8a1a4553ae6263fc9490e33de213e3746f
Parent:     7e2b19fbc7b9c1fd8ee9c79b375fcedb69dd07c9
Author:     Robert Jennings <[EMAIL PROTECTED]>
AuthorDate: Tue Oct 30 11:37:07 2007 -0500
Committer:  James Bottomley <[EMAIL PROTECTED]>
CommitDate: Sat Nov 3 12:10:36 2007 -0500

    [SCSI] ibmvscsi: Prevent IO during partner login
    By setting the request_limit in send_srp_login to 1 we allowed login
    requests to be sent to the server adapter.  If this was not an initial
    login, but was a login after a disconnect with the server, other I/O
    requests could attempt to be processed before the login occured.  These
    I/O requests would fail, sometimes resulting in filesystems getting
    marked read-only.
    To address this we can set the request_limit to 0 while doing the login
    and add an exception where login requests, along with task management
    events, are always passed to the server.
    There is a case where the request_limit had already reached 0 would result
    in all events being sent rather than returning SCSI_MLQUEUE_HOST_BUSY; this
    has also been fixed by this patch.
    Signed-off-by: Robert Jennings <[EMAIL PROTECTED]>
    Signed-off-by: Brian King <[EMAIL PROTECTED]>
    Signed-off-by: James Bottomley <[EMAIL PROTECTED]>
 drivers/scsi/ibmvscsi/ibmvscsi.c |   19 ++++++++++++++-----
 1 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 22d91ee..5f2396c 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -556,7 +556,7 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct 
                                   unsigned long timeout)
        u64 *crq_as_u64 = (u64 *) &evt_struct->crq;
-       int request_status;
+       int request_status = 0;
        int rc;
        /* If we have exhausted our request limit, just fail this request,
@@ -574,6 +574,13 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct 
                if (request_status < -1)
                        goto send_error;
                /* Otherwise, we may have run out of requests. */
+               /* If request limit was 0 when we started the adapter is in the
+                * process of performing a login with the server adapter, or
+                * we may have run out of requests.
+                */
+               else if (request_status == -1 &&
+                        evt_struct->iu.srp.login_req.opcode != SRP_LOGIN_REQ)
+                       goto send_busy;
                /* Abort and reset calls should make it through.
                 * Nothing except abort and reset should use the last two
                 * slots unless we had two or less to begin with.
@@ -633,7 +640,8 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct 
        unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
        free_event_struct(&hostdata->pool, evt_struct);
-       atomic_inc(&hostdata->request_limit);
+       if (request_status != -1)
+               atomic_inc(&hostdata->request_limit);
        return SCSI_MLQUEUE_HOST_BUSY;
@@ -927,10 +935,11 @@ static int send_srp_login(struct ibmvscsi_host_data 
        login->req_buf_fmt = SRP_BUF_FORMAT_DIRECT | SRP_BUF_FORMAT_INDIRECT;
        spin_lock_irqsave(hostdata->host->host_lock, flags);
-       /* Start out with a request limit of 1, since this is negotiated in
-        * the login request we are just sending
+       /* Start out with a request limit of 0, since this is negotiated in
+        * the login request we are just sending and login requests always
+        * get sent by the driver regardless of request_limit.
-       atomic_set(&hostdata->request_limit, 1);
+       atomic_set(&hostdata->request_limit, 0);
        rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
        spin_unlock_irqrestore(hostdata->host->host_lock, flags);
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