[Xen-devel] [PATCH Linux-2.6.18] scsifront: avoid aquiring same lock twice if ring is full

[Juergen Gross <jgross@xxxxxxxx>]

The locking in scsifront_dev_reset_handler() is obviously wrong. In
case of a full ring the host lock is aquired twice.

Fixing this issue enables to get rid of the endless fo loop with an
explicit break statement.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---

diff -r 078f1bb69ea5 drivers/xen/scsifront/scsifront.c
--- a/drivers/xen/scsifront/scsifront.c Wed Dec 10 10:22:39 2014 +0100
+++ b/drivers/xen/scsifront/scsifront.c Tue Jan 13 14:32:33 2015 +0100
@@ -447,12 +447,10 @@ static int scsifront_dev_reset_handler(s
        uint16_t rqid;
        int err = 0;
 
-       for (;;) {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
-               spin_lock_irq(host->host_lock);
+       spin_lock_irq(host->host_lock);
 #endif
-               if (!RING_FULL(&info->ring))
-                       break;
+       while (RING_FULL(&info->ring)) {
                if (err) {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,12)
                        spin_unlock_irq(host->host_lock);

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