[ACPI] acpi_register_gsi() can return error

Current acpi_register_gsi() function has no way to indicate errors to its
callers even though acpi_register_gsi() can fail to register gsi because of
some reasons (out of memory, lack of interrupt vectors, incorrect BIOS, and so
on).  As a result, caller of acpi_register_gsi() cannot handle the case that
acpi_register_gsi() fails.  I think failure of acpi_register_gsi() should be
handled properly.

This series of patches changes acpi_register_gsi() to return negative value on
error, and also changes callers of acpi_register_gsi() to handle failure of
acpi_register_gsi().

This patch changes the type of return value of acpi_register_gsi() from
"unsigned int" to "int" to indicate an error.  If acpi_register_gsi() fails to
register gsi, it returns negative value.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

arch/i386/kernel/acpi/boot.c

@@ -457,7 +457,11 @@ int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 	return 0;
 }
 
-unsigned int acpi_register_gsi(u32 gsi, int edge_level, int active_high_low)
+/*
+ * success: return IRQ number (>=0)
+ * failure: return < 0
+ */
+int acpi_register_gsi(u32 gsi, int edge_level, int active_high_low)
 {
 	unsigned int irq;
 	unsigned int plat_gsi = gsi;

arch/ia64/kernel/acpi.c

@@ -565,7 +565,11 @@ acpi_numa_arch_fixup (void)
 }
 #endif /* CONFIG_ACPI_NUMA */
 
-unsigned int
+/*
+ * success: return IRQ number (>=0)
+ * failure: return < 0
+ */
+int
 acpi_register_gsi (u32 gsi, int edge_level, int active_high_low)
 {
 	if (has_8259 && gsi < 16)

include/linux/acpi.h

@@ -432,7 +432,7 @@ static inline int acpi_boot_table_init(void)
 
 #endif 	/*!CONFIG_ACPI_BOOT*/
 
-unsigned int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low);
+int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low);
 int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
 
 /*