[PATCH 0/1] /dev/port: Handle HAS_IOPORT dependencies

[PATCH 0/1] /dev/port: Handle HAS_IOPORT dependencies

[Niklas Schnelle]

Hi Greg, Hi Arnd,

This is a follow up in my ongoing effort of making inb()/outb() and
similar I/O port accessors compile-time optional. Previously I sent this
as a treewide series titled "treewide: Remove I/O port accessors for
HAS_IOPORT=n" with the latest being its 5th version[0]. With a significant
subset of patches merged I've changed over to per-subsystem series. These
series are stand alone and should be merged via the relevant tree such
that with all subsystems complete we can follow this up with the final
patch that will make the I/O port accessors compile-time optional.

The current state of the full series with changes to the remaining
subsystems and the aforementioned final patch can be found for your
convenience on my git.kernel.org tree in the has_ioport_v6 branch[1] with
signed tags. As for compile-time vs runtime see Linus' reply to my first
attempt[2].

Thanks,
Niklas

[0] https://lore.kernel.org/all/20230522105049.1467313-1-schnelle@linux.ibm.com/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git/log/?h=has_ioport_v6
[2] https://lore.kernel.org/lkml/CAHk-=wg80je=K7madF4e7WrRNp37e3qh6y10Svhdc7O8SZ_-8g@mail.gmail.com/

Niklas Schnelle (1):
  /dev/port: don't compile file operations without CONFIG_DEVPORT

 drivers/char/mem.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

-- 
2.40.1

[PATCH 1/1] /dev/port: don't compile file operations without CONFIG_DEVPORT

[Niklas Schnelle]

In the future inb() and friends will not be available when compiling
with CONFIG_HAS_IOPORT=n so we must only try to access them here if
CONFIG_DEVPORT is set which depends on HAS_IOPORT.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
Note: This patch does not depend any not-yet-mainline HAS_IOPORT changes
and may be merged via subsystem specific trees at your earliest
convenience.

 drivers/char/mem.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 3c6670cf905f..7904e2bb6427 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -383,6 +383,7 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma)
 	return 0;
 }
 
+#ifdef CONFIG_DEVPORT
 static ssize_t read_port(struct file *file, char __user *buf,
 			 size_t count, loff_t *ppos)
 {
@@ -424,6 +425,7 @@ static ssize_t write_port(struct file *file, const char __user *buf,
 	*ppos = i;
 	return tmp-buf;
 }
+#endif
 
 static ssize_t read_null(struct file *file, char __user *buf,
 			 size_t count, loff_t *ppos)
@@ -653,12 +655,14 @@ static const struct file_operations null_fops = {
 	.uring_cmd	= uring_cmd_null,
 };
 
-static const struct file_operations __maybe_unused port_fops = {
+#ifdef CONFIG_DEVPORT
+static const struct file_operations port_fops = {
 	.llseek		= memory_lseek,
 	.read		= read_port,
 	.write		= write_port,
 	.open		= open_port,
 };
+#endif
 
 static const struct file_operations zero_fops = {
 	.llseek		= zero_lseek,
-- 
2.40.1