From: Bart Van Assche <bart.vanassche@sandisk.com>
Date: Fri, 22 Apr 2016 21:14:15 +0000 (-0700)
Subject: IB/srp: Avoid that mapping failure triggers an infinite loop
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ffc548bb3601f0250474afcfa10ceb0b8b8b9764;p=linux-beck.git

IB/srp: Avoid that mapping failure triggers an infinite loop

The srp_queuecommand() function translates ENOMEM into QUEUE_FULL
which causes the SCSI mid-layer to retry the command. All other
error codes are translated into DID_ERROR which causes the SCSI
command to fail. Return E2BIG if mapping will always fail to
prevent that the SCSI mid-layer keeps resubmitting a command
forever.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 92d2d98c9831..fbd2edbedf05 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1681,6 +1681,8 @@ map_complete:
 
 unmap:
 	srp_unmap_data(scmnd, ch, req);
+	if (ret == -ENOMEM && req->nmdesc >= target->mr_pool_size)
+		ret = -E2BIG;
 	return ret;
 }