[PATCH] sg: fix leak when dio setup fails

[Douglas Gilbert <dougg@torque.net>]

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Further to this thread started by Bryan Holty:
http://marc.theaimsgroup.com/?l=linux-scsi&m=114306885116728&w=2

Here is the reworked patch again. This time it has been
tested with a program provided by Bryan. The patch is
against lk 2.6.16 .

Changelog:
  - when the sg driver is unable to setup direct IO,
    free that scatter gather list prior to falling
    back to indirect IO

Signed-off-by: Douglas Gilbert <dougg@torque.net>

Doug Gilbert


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--- linux/drivers/scsi/sg.c	2006-03-20 10:08:49.000000000 -0500
+++ linux/drivers/scsi/sg.c2616dio_lk	2006-03-22 18:26:23.000000000 -0500
@@ -1834,8 +1834,10 @@
 	res = st_map_user_pages(schp->buffer, mx_sc_elems,
 				(unsigned long)hp->dxferp, dxfer_len, 
 				(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
-	if (res <= 0)
+	if (res <= 0) {
+		sg_remove_scat(schp);
 		return 1;
+	}
 	schp->k_use_sg = res;
 	schp->dio_in_use = 1;
 	hp->info |= SG_INFO_DIRECT_IO;