[SCSI] ipr: fix eeh recovery for 64-bit adapters

In some scenarios, an EEH error can take a long time to be detected, since the
driver issues an MMIO read only after a device reset command times out and we
try to reset the adapter. This patch adds some code in ipr_cancel_op() to read
a hardware register so we detect the error earlier in case the op is being
aborted because of a timeout caused by a frozen adapter slot.

Another problem in such scenarios is that in __ipr_eh_host_reset() we change the
dump state flag from WAIT_FOR_DUMP to GET_DUMP, and the flag is later changed
from GET_DUMP to READ_DUMP in ipr_reset_restore_cfg_space(). However, if when
__ipr_eh_host_reset() is called by the SCSI error handling the function
ipr_reset_restore_cfg_space() has already been called by the PCI EEH code, we
end up with the flag in an inconsistent state. This patch also prevents this
problem.

Signed-off-by: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 67b169b7a5be..b538f0883fd2 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4613,11 +4613,13 @@ static int __ipr_eh_host_reset(struct scsi_cmnd * scsi_cmd)
         ENTER;
         ioa_cfg = (struct ipr_ioa_cfg *) scsi_cmd->device->host->hostdata;
 
-        dev_err(&ioa_cfg->pdev->dev,
-                "Adapter being reset as a result of error recovery.\n");
+        if (!ioa_cfg->in_reset_reload) {
+                dev_err(&ioa_cfg->pdev->dev,
+                        "Adapter being reset as a result of error recovery.\n");
 
-        if (WAIT_FOR_DUMP == ioa_cfg->sdt_state)
-                ioa_cfg->sdt_state = GET_DUMP;
+                if (WAIT_FOR_DUMP == ioa_cfg->sdt_state)
+                        ioa_cfg->sdt_state = GET_DUMP;
+        }
 
         rc = ipr_reset_reload(ioa_cfg, IPR_SHUTDOWN_ABBREV);
 
@@ -4907,7 +4909,7 @@ static int ipr_cancel_op(struct scsi_cmnd * scsi_cmd)
         struct ipr_ioa_cfg *ioa_cfg;
         struct ipr_resource_entry *res;
         struct ipr_cmd_pkt *cmd_pkt;
-        u32 ioasc;
+        u32 ioasc, int_reg;
         int op_found = 0;
 
         ENTER;
@@ -4920,7 +4922,17 @@ static int ipr_cancel_op(struct scsi_cmnd * scsi_cmd)
          */
         if (ioa_cfg->in_reset_reload || ioa_cfg->ioa_is_dead)
                 return FAILED;
-        if (!res || !ipr_is_gscsi(res))
+        if (!res)
+                return FAILED;
+
+        /*
+         * If we are aborting a timed out op, chances are that the timeout was caused
+         * by a still not detected EEH error. In such cases, reading a register will
+         * trigger the EEH recovery infrastructure.
+         */
+        int_reg = readl(ioa_cfg->regs.sense_interrupt_reg);
+
+        if (!ipr_is_gscsi(res))
                 return FAILED;
 
         list_for_each_entry(ipr_cmd, &ioa_cfg->pending_q, queue) {