[SCSI] libiscsi_tcp: use kmap in xmit path
Mike Christie [Thu, 17 Mar 2011 21:22:17 +0000 (16:22 -0500)]
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>

drivers/scsi/libiscsi_tcp.c
include/scsi/libiscsi_tcp.h

index 8eeb39f..e98ae33 100644 (file)
@@ -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;
        }
index 741ae7e..e6b9fd2 100644 (file)
@@ -47,6 +47,7 @@ struct iscsi_segment {
        struct scatterlist      *sg;
        void                    *sg_mapped;
        unsigned int            sg_offset;
+       bool                    atomic_mapped;
 
        iscsi_segment_done_fn_t *done;
 };