From: Niklas Schnelle <schnelle@linux.ibm.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
John Garry <john.garry@huawei.com>,
Nick Hu <nickhu@andestech.com>, Greentime Hu <green.hu@gmail.com>,
Vincent Chen <deanbo422@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-pci@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-csky@vger.kernel.org
Subject: Re: [RFC 30/32] /dev/port: don't compile file operations without CONFIG_DEVPORT
Date: Wed, 29 Dec 2021 11:25:12 +0100 [thread overview]
Message-ID: <b9d0c0b88ef66f9beb51a880e765177670a76394.camel@linux.ibm.com> (raw)
In-Reply-To: <YcrIHxTDipVNUuCA@kroah.com>
On Tue, 2021-12-28 at 09:17 +0100, Greg Kroah-Hartman wrote:
> On Mon, Dec 27, 2021 at 05:43:15PM +0100, Niklas Schnelle wrote:
> > 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>
> > ---
> > 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 cc296f0823bd..c1373617153f 100644
> > --- a/drivers/char/mem.c
> > +++ b/drivers/char/mem.c
> > @@ -402,6 +402,7 @@ 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)
> > {
> > @@ -443,6 +444,7 @@ 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)
> > @@ -665,12 +667,14 @@ static const struct file_operations null_fops = {
> > .splice_write = splice_write_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
>
> Why is this #ifdef needed if it is already __maybe_unused?
Because read_port() calls inb() and write_port() calls outb() they
wouldn't compile once these are no longer defined. Then however the
read_port/write_port symbols in the struct initialization above
couldn't be resolved.
>
> In looking closer, this change could be taken now as the use of this
> variable already is behind this same #ifdef statement, right?
Yes
>
> thanks,
>
> greg k-h
next prev parent reply other threads:[~2021-12-29 10:26 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-27 16:42 [RFC 00/32] Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options Niklas Schnelle
2021-12-27 16:42 ` [RFC 01/32] Kconfig: introduce and depend on LEGACY_PCI Niklas Schnelle
2021-12-27 17:48 ` Guenter Roeck
2021-12-28 2:09 ` Mauro Carvalho Chehab
2021-12-28 8:21 ` Greg Kroah-Hartman
2021-12-28 9:15 ` Mauro Carvalho Chehab
2021-12-28 10:58 ` Niklas Schnelle
2021-12-28 12:01 ` Greg Kroah-Hartman
2021-12-28 12:54 ` Mauro Carvalho Chehab
2021-12-28 15:06 ` Niklas Schnelle
2021-12-28 17:12 ` Mauro Carvalho Chehab
2021-12-29 11:45 ` Niklas Schnelle
2021-12-29 12:12 ` Mauro Carvalho Chehab
2021-12-29 16:03 ` Bjorn Helgaas
2021-12-29 16:55 ` Niklas Schnelle
2022-01-05 17:42 ` John Garry
2022-01-05 19:47 ` Bjorn Helgaas
2022-01-06 17:41 ` John Garry
2022-01-06 18:14 ` Bjorn Helgaas
2022-01-07 17:16 ` John Garry
2022-01-10 9:34 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 02/32] Kconfig: introduce HAS_IOPORT option and select it as necessary Niklas Schnelle
2021-12-28 10:08 ` Geert Uytterhoeven
2021-12-29 1:20 ` Michael Schmitz
2021-12-29 3:41 ` Arnd Bergmann
2021-12-29 4:15 ` Michael Schmitz
2021-12-30 1:48 ` Arnd Bergmann
2021-12-30 3:44 ` Michael Schmitz
2021-12-31 11:28 ` Niklas Schnelle
2021-12-31 16:04 ` Arnd Bergmann
2021-12-31 21:55 ` Michael Schmitz
2021-12-28 16:32 ` Mauro Carvalho Chehab
2021-12-27 16:42 ` [RFC 03/32] ACPI: Kconfig: add HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 16:47 ` Rafael J. Wysocki
2021-12-27 17:02 ` Niklas Schnelle
2021-12-27 17:12 ` Rafael J. Wysocki
2021-12-27 17:15 ` Rafael J. Wysocki
2021-12-27 17:43 ` Niklas Schnelle
2021-12-28 15:20 ` Rafael J. Wysocki
2021-12-28 16:31 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 04/32] parport: PC style parport depends on HAS_IOPORT Niklas Schnelle
2021-12-28 10:14 ` Geert Uytterhoeven
2021-12-28 14:21 ` Niklas Schnelle
2021-12-29 2:58 ` Arnd Bergmann
2021-12-27 16:42 ` [RFC 05/32] char: impi, tpm: depend " Niklas Schnelle
2021-12-28 10:17 ` Geert Uytterhoeven
2021-12-28 12:13 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 06/32] speakup: Kconfig: add HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 17:52 ` Samuel Thibault
2021-12-27 16:42 ` [RFC 07/32] Input: gameport: add ISA and " Niklas Schnelle
2021-12-27 16:42 ` [RFC 08/32] comedi: Kconfig: add " Niklas Schnelle
2021-12-27 16:42 ` [RFC 09/32] sound: " Niklas Schnelle
2021-12-27 16:42 ` [RFC 10/32] i2c: " Niklas Schnelle
2021-12-28 10:21 ` Geert Uytterhoeven
2021-12-28 12:13 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 11/32] Input: " Niklas Schnelle
2021-12-28 10:23 ` Geert Uytterhoeven
2021-12-27 16:42 ` [RFC 12/32] iio: adc: " Niklas Schnelle
2021-12-28 10:32 ` Geert Uytterhoeven
2021-12-28 12:50 ` Niklas Schnelle
2021-12-28 17:01 ` Jonathan Cameron
2022-01-30 15:05 ` Jonathan Cameron
2021-12-27 16:42 ` [RFC 13/32] hwmon: " Niklas Schnelle
2021-12-27 18:07 ` Guenter Roeck
2021-12-27 16:42 ` [RFC 14/32] leds: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 15/32] media: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 16/32] misc: handle " Niklas Schnelle
2021-12-28 8:15 ` Greg Kroah-Hartman
2021-12-27 16:43 ` [RFC 17/32] net: Kconfig: add " Niklas Schnelle
2021-12-27 17:28 ` Marc Kleine-Budde
2021-12-27 16:43 ` [RFC 18/32] pcmcia: " Niklas Schnelle
2021-12-27 18:41 ` Dominik Brodowski
2021-12-27 16:43 ` [RFC 19/32] platform: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 20/32] pnp: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 21/32] power: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 22/32] video: handle " Niklas Schnelle
2021-12-27 16:43 ` [RFC 23/32] rtc: Kconfig: add " Niklas Schnelle
2021-12-27 16:43 ` [RFC 24/32] scsi: " Niklas Schnelle
2021-12-28 10:40 ` Geert Uytterhoeven
2021-12-27 16:43 ` [RFC 25/32] watchdog: " Niklas Schnelle
2021-12-27 18:03 ` Guenter Roeck
2021-12-28 9:58 ` Niklas Schnelle
2021-12-27 16:43 ` [RFC 26/32] drm: handle " Niklas Schnelle
2022-01-03 6:11 ` Gerd Hoffmann
2021-12-27 16:43 ` [RFC 27/32] PCI/sysfs: make I/O resource depend on HAS_IOPORT Niklas Schnelle
2021-12-27 22:04 ` Bjorn Helgaas
2021-12-27 16:43 ` [RFC 28/32] PCI: make quirk using inw() " Niklas Schnelle
2021-12-27 22:33 ` Bjorn Helgaas
2021-12-28 15:25 ` Niklas Schnelle
2021-12-28 16:35 ` Bjorn Helgaas
2021-12-28 16:52 ` Niklas Schnelle
2021-12-28 17:28 ` Bjorn Helgaas
2021-12-27 16:43 ` [RFC 29/32] firmware: dmi-sysfs: handle HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 16:43 ` [RFC 30/32] /dev/port: don't compile file operations without CONFIG_DEVPORT Niklas Schnelle
2021-12-28 8:17 ` Greg Kroah-Hartman
2021-12-29 10:25 ` Niklas Schnelle [this message]
2021-12-29 10:38 ` Greg Kroah-Hartman
2021-12-30 16:19 ` Arnd Bergmann
2021-12-27 16:43 ` [RFC 31/32] usb: handle HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 20:36 ` Alan Stern
2021-12-31 11:06 ` Niklas Schnelle
2021-12-31 17:15 ` Alan Stern
2022-01-03 11:35 ` Niklas Schnelle
2022-01-03 16:15 ` Alan Stern
2021-12-27 16:43 ` [RFC 32/32] asm-generic/io.h: drop inb() etc for HAS_IOPORT=n Niklas Schnelle
2022-01-06 17:45 ` [RFC 00/32] Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options John Garry
2022-01-07 7:21 ` Niklas Schnelle
2022-01-07 16:57 ` John Garry
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