[SCSI] libiscsi_tcp: use kmap in xmit path

The xmit path can sleep with a page kmapped in the network
xmit code while it waits for space to open up, so we have to use
kmap instead of kmap atomic in that path.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index 8eeb39ffa37f..e98ae33f1295 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -132,14 +132,25 @@ static void iscsi_tcp_segment_map(struct iscsi_segment *segment, int recv)
         if (page_count(sg_page(sg)) >= 1 && !recv)
                 return;
 
-        segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
+        if (recv) {
+                segment->atomic_mapped = true;
+                segment->sg_mapped = kmap_atomic(sg_page(sg), KM_SOFTIRQ0);
+        } else {
+                segment->atomic_mapped = false;
+                /* the xmit path can sleep with the page mapped so use kmap */
+                segment->sg_mapped = kmap(sg_page(sg));
+        }
+
         segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
 }
 
 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 {
         if (segment->sg_mapped) {
-                kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
+                if (segment->atomic_mapped)
+                        kunmap_atomic(segment->sg_mapped, KM_SOFTIRQ0);
+                else
+                        kunmap(sg_page(segment->sg));
                 segment->sg_mapped = NULL;
                 segment->data = NULL;
         }