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authorThomas Gleixner <tglx@linutronix.de>2020-12-10 20:26:04 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-12-15 16:19:37 +0100
commit62ebcda8a8dfa4aeaa3288020a082787910afebc (patch)
treed5671333409d71e98bf96ccbe8af5c096f81729d /drivers/xen/events
parentf7a6f994b4f0ee69c656dda3da11431d92d6b08f (diff)
downloadlinux-62ebcda8a8dfa4aeaa3288020a082787910afebc.tar.gz
xen/events: Reduce irq_info:: Spurious_cnt storage size
To prepare for interrupt spreading reduce the storage size of
irq_info::spurious_cnt to u8 so the required flag for the spreading logic
will not increase the storage size.

Protect the usage site against overruns.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20201210194045.360198201@linutronix.de


Diffstat (limited to 'drivers/xen/events')
-rw-r--r--drivers/xen/events/events_base.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 679b2cbd2de4..b352440963ee 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -95,7 +95,7 @@ struct irq_info {
 	struct list_head list;
 	struct list_head eoi_list;
 	short refcnt;
-	short spurious_cnt;
+	u8 spurious_cnt;
 	enum xen_irq_type type; /* type */
 	unsigned irq;
 	evtchn_port_t evtchn;   /* event channel */
@@ -528,8 +528,10 @@ static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious)
 		return;
 
 	if (spurious) {
-		if ((1 << info->spurious_cnt) < (HZ << 2))
-			info->spurious_cnt++;
+		if ((1 << info->spurious_cnt) < (HZ << 2)) {
+			if (info->spurious_cnt != 0xFF)
+				info->spurious_cnt++;
+		}
 		if (info->spurious_cnt > 1) {
 			delay = 1 << (info->spurious_cnt - 2);
 			if (delay > HZ)