| Message ID | 20211227164317.4146918-31-schnelle@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options | expand |
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? In looking closer, this change could be taken now as the use of this variable already is behind this same #ifdef statement, right? thanks, greg k-h
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
On Wed, Dec 29, 2021 at 11:25:12AM +0100, Niklas Schnelle wrote: > 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 Great, feel free to send this individually, not as a RFC patch, and I will be glad to queue it up. thanks, greg k-h
On Wed, Dec 29, 2021 at 5:38 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > > > -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 > > Great, feel free to send this individually, not as a RFC patch, and I > will be glad to queue it up. I think this patch should contain the 'depends on HAS_IOPORT' that is currently added in a different patch (char: impi, tpm: depend on HAS_IOPORT). However, we can't merge that version until HAS_IOPORT is actually added to the kernel. Arnd
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 static const struct file_operations zero_fops = { .llseek = zero_lseek,