xen: events: simplify comment

It is never valid assume any particular relationship between a Xen
PIRQ number and and Linux IRQ number so there is no need to hedge when
saying so.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/events.c

@@ -583,13 +583,9 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
 	return xen_map_pirq_gsi(gsi, gsi, shareable, name);
 }
 
-/* xen_map_pirq_gsi might allocate irqs from the top down, as a
- * consequence don't assume that the irq number returned has a low value
- * or can be used as a pirq number unless you know otherwise.
- *
- * One notable exception is when xen_map_pirq_gsi is called passing an
- * hardware gsi as argument, in that case the irq number returned
- * matches the gsi number passed as second argument.
+/*
+ * Do not make any assumptions regarding the relationship between the
+ * IRQ number returned here and the Xen pirq argument.
  *
  * Note: We don't assign an event channel until the irq actually started
  * up.  Return an existing irq if we've already got one for the gsi.

include/xen/events.h

@@ -68,9 +68,7 @@ int xen_set_callback_via(uint64_t via);
 void xen_evtchn_do_upcall(struct pt_regs *regs);
 void xen_hvm_evtchn_do_upcall(void);
 
-/* Allocate an irq for a physical interrupt, given a gsi.  "Legacy"
- * GSIs are identity mapped; others are dynamically allocated as
- * usual. */
+/* Allocate an irq for a physical interrupt, given a gsi. */
 int xen_allocate_pirq(unsigned gsi, int shareable, char *name);
 int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name);