Once the reserved page array is unused we can reset the
'res_in_use' state; here we can do a lazy update without
holding the mutex as we only need to check against
concurrent access, not concurrent release.

Fixes: 1bc0eb0 ("scsi: sg: protect accesses to 'reserved' page array")
Signed-off-by: Hannes Reinecke <[email protected]>
---
 drivers/scsi/sg.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 8147147..06503c1 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2056,6 +2056,8 @@ static long sg_compat_ioctl(struct file *filp, unsigned 
int cmd_in, unsigned lon
        req_schp->page_order = 0;
        req_schp->sglist_len = 0;
        srp->res_used = 0;
+       /* Called without mutex lock to avoid deadlock */
+       sfp->res_in_use = 0;
 }
 
 static Sg_request *
-- 
1.8.5.6

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