xen-scsifront: don't deadlock if the ring becomes full

scsifront_action_handler() will deadlock on host->host_lock, if the
ring is full and it has to wait for entries to become available.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index 7e88659bf5af9ba2ff4ad5caefde0e504673959f..cc14c8ddd369580cc89b63cdf2cafb6c7947acb8 100644 (file)
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -541,8 +541,9 @@ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
        if (!shadow)
                return FAILED;
 
+       spin_lock_irq(host->host_lock);
+
        for (;;) {
-               spin_lock_irq(host->host_lock);
                if (!RING_FULL(&info->ring)) {
                        ring_req = scsifront_command2ring(info, sc, shadow);
                        if (ring_req)