[PATCH V3] UIO: make maximum memory and port regions configurable

[Qiang Su]

Now each uio device can only support 5 memory regions and
5 port regions. It may be far from enough for some big system.
On the other hand, the hard-coded style is not flexible.
So make these values configurable by menuconfig, thus users
can easily expand them according to their actual situation.

Consider the marco is used as array index, so a range for
the config is set in menuconfig. The range is set as 1 to 512.
The default value is still set as 5 to keep consistent with
current code.

Signed-off-by: Qiang Su <suqiang4@xxxxxxxxxx>
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Reviewed-by: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
also make port regions configurable in menuconfig.
fix kbuild errors.
---
Changes since v2:
provide more information in the help texts.
---
 drivers/uio/Kconfig        | 28 ++++++++++++++++++++++++++++
 include/linux/uio_driver.h |  4 ++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 202ee81cfc2b..669000df80df 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -165,4 +165,32 @@ config UIO_HV_GENERIC
 	  to network and storage devices from userspace.
 
 	  If you compile this as a module, it will be called uio_hv_generic.
+
+config MAX_UIO_MAPS
+	depends on UIO
+	int "Maximum of memory nodes each uio device support(1-512)"
+	range 1 512
+	default 5
+	help
+	  make the max number of memory regions in uio device configurable.
+	  For some big system, you may need to map more memory regions
+	  than the default 5. For example, your driver need to access 10
+	  discontinuous address space, thus you need to set this value.
+	  to 10 or greater.
+
+	  If you do not understand, just keep the default value.
+
+config MAX_UIO_PORT_REGIONS
+	depends on UIO
+	int "Maximum of port regions each uio device support(1-512)"
+	range 1 512
+	default 5
+	help
+	  make the max number of port regions in uio device configurable.
+	  For some big system, you may need to use more port regions than
+	  the default 5. For example, your driver need to use 10 port regions
+	  of gpio type, then you need to set this value to 10 or greater.
+
+	  If you do not understand, just keep the default value.
+
 endif
diff --git a/include/linux/uio_driver.h b/include/linux/uio_driver.h
index 01081c4726c0..5dc60088834c 100644
--- a/include/linux/uio_driver.h
+++ b/include/linux/uio_driver.h
@@ -44,7 +44,7 @@ struct uio_mem {
 	struct uio_map		*map;
 };
 
-#define MAX_UIO_MAPS	5
+#define MAX_UIO_MAPS	CONFIG_MAX_UIO_MAPS
 
 struct uio_portio;
 
@@ -64,7 +64,7 @@ struct uio_port {
 	struct uio_portio	*portio;
 };
 
-#define MAX_UIO_PORT_REGIONS	5
+#define MAX_UIO_PORT_REGIONS	CONFIG_MAX_UIO_PORT_REGIONS
 
 struct uio_device {
         struct module           *owner;
-- 
2.12.3