Only request the SCSI mid-layer to retry a SCSI command after a
temporary mapping failure (-ENOMEM) but not after a permanent
mapping failure. This patch avoids that SCSI commands are retried
indefinitely if a permanent memory mapping failure occurs.

Signed-off-by: Bart Van Assche <[email protected]>
Cc: Roland Dreier <[email protected]>
Cc: David Dillow <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Cc: Vu Pham <[email protected]>
Cc: Sebastian Parschauer <[email protected]>
---
 drivers/infiniband/ulp/srp/ib_srp.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c 
b/drivers/infiniband/ulp/srp/ib_srp.c
index 1c4b0d3..af94381 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1564,7 +1564,7 @@ static int srp_queuecommand(struct Scsi_Host *shost, 
struct scsi_cmnd *scmnd)
        struct srp_cmd *cmd;
        struct ib_device *dev;
        unsigned long flags;
-       int len, result;
+       int len, result, ret = SCSI_MLQUEUE_HOST_BUSY;
        const bool in_scsi_eh = !in_interrupt() && current == shost->ehandler;
 
        /*
@@ -1580,6 +1580,7 @@ static int srp_queuecommand(struct Scsi_Host *shost, 
struct scsi_cmnd *scmnd)
        if (unlikely(result)) {
                scmnd->result = result;
                scmnd->scsi_done(scmnd);
+               ret = 0;
                goto unlock_rport;
        }
 
@@ -1613,7 +1614,12 @@ static int srp_queuecommand(struct Scsi_Host *shost, 
struct scsi_cmnd *scmnd)
        len = srp_map_data(scmnd, target, req);
        if (len < 0) {
                shost_printk(KERN_ERR, target->scsi_host,
-                            PFX "Failed to map data\n");
+                            PFX "Failed to map data (%d)\n", len);
+               if (len != -ENOMEM) {
+                       scmnd->result = DID_ERROR << 16;
+                       scmnd->scsi_done(scmnd);
+                       ret = 0;
+               }
                goto err_iu;
        }
 
@@ -1625,11 +1631,13 @@ static int srp_queuecommand(struct Scsi_Host *shost, 
struct scsi_cmnd *scmnd)
                goto err_unmap;
        }
 
+       ret = 0;
+
 unlock_rport:
        if (in_scsi_eh)
                mutex_unlock(&rport->mutex);
 
-       return 0;
+       return ret;
 
 err_unmap:
        srp_unmap_data(scmnd, target, req);
@@ -1643,10 +1651,7 @@ err_iu:
 err_unlock:
        spin_unlock_irqrestore(&target->lock, flags);
 
-       if (in_scsi_eh)
-               mutex_unlock(&rport->mutex);
-
-       return SCSI_MLQUEUE_HOST_BUSY;
+       goto unlock_rport;
 }
 
 /*
-- 
1.8.4.5

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