* [PATCH 1/2] add typeof_member() macro
@ 2019-05-29 19:07 Alexey Dobriyan
2019-05-29 19:11 ` [PATCH 2/2] proc: use " Alexey Dobriyan
2019-05-30 11:37 ` [PATCH 1/2] add " David Laight
0 siblings, 2 replies; 6+ messages in thread
From: Alexey Dobriyan @ 2019-05-29 19:07 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel
Add typeof_member() macro so that types can be exctracted without
introducing dummy variables.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
include/linux/kernel.h | 2 ++
1 file changed, 2 insertions(+)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -88,6 +88,8 @@
*/
#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
+#define typeof_member(T, m) typeof(((T*)0)->m)
+
#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
#define DIV_ROUND_DOWN_ULL(ll, d) \
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/2] proc: use typeof_member() macro
2019-05-29 19:07 [PATCH 1/2] add typeof_member() macro Alexey Dobriyan
@ 2019-05-29 19:11 ` Alexey Dobriyan
2019-05-29 22:33 ` Andrew Morton
2019-05-30 11:37 ` [PATCH 1/2] add " David Laight
1 sibling, 1 reply; 6+ messages in thread
From: Alexey Dobriyan @ 2019-05-29 19:11 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel
Don't repeat function signatures twice.
This is a kind-of-precursor for "struct proc_ops".
Note:
typeof(pde->proc_fops->...) ...;
can't be used because ->proc_fops is "const struct file_operations *".
"const" prevents assignment down the code and it can't be deleted
in the type system.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
Note 2: 100% false positives with checkpatch.pl :^)
fs/proc/inode.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -200,7 +200,8 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
struct proc_dir_entry *pde = PDE(file_inode(file));
loff_t rv = -EINVAL;
if (use_pde(pde)) {
- loff_t (*llseek)(struct file *, loff_t, int);
+ typeof_member(struct file_operations, llseek) llseek;
+
llseek = pde->proc_fops->llseek;
if (!llseek)
llseek = default_llseek;
@@ -212,10 +213,11 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
- ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
struct proc_dir_entry *pde = PDE(file_inode(file));
ssize_t rv = -EIO;
if (use_pde(pde)) {
+ typeof_member(struct file_operations, read) read;
+
read = pde->proc_fops->read;
if (read)
rv = read(file, buf, count, ppos);
@@ -226,10 +228,11 @@ static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count,
static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
- ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
struct proc_dir_entry *pde = PDE(file_inode(file));
ssize_t rv = -EIO;
if (use_pde(pde)) {
+ typeof_member(struct file_operations, write) write;
+
write = pde->proc_fops->write;
if (write)
rv = write(file, buf, count, ppos);
@@ -242,8 +245,9 @@ static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
{
struct proc_dir_entry *pde = PDE(file_inode(file));
__poll_t rv = DEFAULT_POLLMASK;
- __poll_t (*poll)(struct file *, struct poll_table_struct *);
if (use_pde(pde)) {
+ typeof_member(struct file_operations, poll) poll;
+
poll = pde->proc_fops->poll;
if (poll)
rv = poll(file, pts);
@@ -256,8 +260,9 @@ static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigne
{
struct proc_dir_entry *pde = PDE(file_inode(file));
long rv = -ENOTTY;
- long (*ioctl)(struct file *, unsigned int, unsigned long);
if (use_pde(pde)) {
+ typeof_member(struct file_operations, unlocked_ioctl) ioctl;
+
ioctl = pde->proc_fops->unlocked_ioctl;
if (ioctl)
rv = ioctl(file, cmd, arg);
@@ -271,8 +276,9 @@ static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned
{
struct proc_dir_entry *pde = PDE(file_inode(file));
long rv = -ENOTTY;
- long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
if (use_pde(pde)) {
+ typeof_member(struct file_operations, compat_ioctl) compat_ioctl;
+
compat_ioctl = pde->proc_fops->compat_ioctl;
if (compat_ioctl)
rv = compat_ioctl(file, cmd, arg);
@@ -286,8 +292,9 @@ static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
{
struct proc_dir_entry *pde = PDE(file_inode(file));
int rv = -EIO;
- int (*mmap)(struct file *, struct vm_area_struct *);
if (use_pde(pde)) {
+ typeof_member(struct file_operations, mmap) mmap;
+
mmap = pde->proc_fops->mmap;
if (mmap)
rv = mmap(file, vma);
@@ -305,7 +312,7 @@ proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
unsigned long rv = -EIO;
if (use_pde(pde)) {
- typeof(proc_reg_get_unmapped_area) *get_area;
+ typeof_member(struct file_operations, get_unmapped_area) get_area;
get_area = pde->proc_fops->get_unmapped_area;
#ifdef CONFIG_MMU
@@ -326,8 +333,8 @@ static int proc_reg_open(struct inode *inode, struct file *file)
{
struct proc_dir_entry *pde = PDE(inode);
int rv = 0;
- int (*open)(struct inode *, struct file *);
- int (*release)(struct inode *, struct file *);
+ typeof_member(struct file_operations, open) open;
+ typeof_member(struct file_operations, release) release;
struct pde_opener *pdeo;
/*
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] proc: use typeof_member() macro
2019-05-29 19:11 ` [PATCH 2/2] proc: use " Alexey Dobriyan
@ 2019-05-29 22:33 ` Andrew Morton
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2019-05-29 22:33 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: linux-kernel
On Wed, 29 May 2019 22:11:10 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> Don't repeat function signatures twice.
>
> This is a kind-of-precursor for "struct proc_ops".
>
> Note:
>
> typeof(pde->proc_fops->...) ...;
>
> can't be used because ->proc_fops is "const struct file_operations *".
> "const" prevents assignment down the code and it can't be deleted
> in the type system.
>
> ...
>
> --- a/fs/proc/inode.c
> +++ b/fs/proc/inode.c
> @@ -200,7 +200,8 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
> struct proc_dir_entry *pde = PDE(file_inode(file));
> loff_t rv = -EINVAL;
> if (use_pde(pde)) {
> - loff_t (*llseek)(struct file *, loff_t, int);
> + typeof_member(struct file_operations, llseek) llseek;
ooh. That's pretty nifty.
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH 1/2] add typeof_member() macro
2019-05-29 19:07 [PATCH 1/2] add typeof_member() macro Alexey Dobriyan
2019-05-29 19:11 ` [PATCH 2/2] proc: use " Alexey Dobriyan
@ 2019-05-30 11:37 ` David Laight
2019-05-30 11:53 ` Joe Perches
2019-05-30 19:57 ` Alexey Dobriyan
1 sibling, 2 replies; 6+ messages in thread
From: David Laight @ 2019-05-30 11:37 UTC (permalink / raw)
To: 'Alexey Dobriyan', akpm; +Cc: linux-kernel
From: Alexey Dobriyan
> Sent: 29 May 2019 20:07
>
> Add typeof_member() macro so that types can be exctracted without
> introducing dummy variables.
>
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>
> include/linux/kernel.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -88,6 +88,8 @@
> */
> #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
>
> +#define typeof_member(T, m) typeof(((T*)0)->m)
Should probably be 't' (not 'T') and upper case ?
Hmmm.... the #define is longer that what it expands to ...
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] add typeof_member() macro
2019-05-30 11:37 ` [PATCH 1/2] add " David Laight
@ 2019-05-30 11:53 ` Joe Perches
2019-05-30 19:57 ` Alexey Dobriyan
1 sibling, 0 replies; 6+ messages in thread
From: Joe Perches @ 2019-05-30 11:53 UTC (permalink / raw)
To: David Laight, 'Alexey Dobriyan', akpm; +Cc: linux-kernel
On Thu, 2019-05-30 at 11:37 +0000, David Laight wrote:
> From: Alexey Dobriyan
> > Sent: 29 May 2019 20:07
> >
> > Add typeof_member() macro so that types can be exctracted without
> > introducing dummy variables.
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> > ---
> >
> > include/linux/kernel.h | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > --- a/include/linux/kernel.h
> > +++ b/include/linux/kernel.h
> > @@ -88,6 +88,8 @@
> > */
> > #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
> >
> > +#define typeof_member(T, m) typeof(((T*)0)->m)
>
> Should probably be 't' (not 'T') and upper case ?
>
> Hmmm.... the #define is longer that what it expands to ...
While I did object to the avoidance in the obvious
misnaming of FIELD_SIZEOF, this could reasonably
be named FIELD_TYPEOF for symmetry.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] add typeof_member() macro
2019-05-30 11:37 ` [PATCH 1/2] add " David Laight
2019-05-30 11:53 ` Joe Perches
@ 2019-05-30 19:57 ` Alexey Dobriyan
1 sibling, 0 replies; 6+ messages in thread
From: Alexey Dobriyan @ 2019-05-30 19:57 UTC (permalink / raw)
To: David Laight; +Cc: akpm, linux-kernel
On Thu, May 30, 2019 at 11:37:42AM +0000, David Laight wrote:
> From: Alexey Dobriyan
> > +#define typeof_member(T, m) typeof(((T*)0)->m)
>
> Should probably be 't' (not 'T') and upper case ?
T comes from C++ where they uppercase types in template arguments.
It makes sense as types stand out sligthly around lowercase identifiers.
> Hmmm.... the #define is longer that what it expands to ...
It hides cast of 0 which is implementation detail :^)
Proper syntax would be
typeof(struct foo::bar)
but one can only dream.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2019-05-29 19:07 [PATCH 1/2] add typeof_member() macro Alexey Dobriyan
2019-05-29 19:11 ` [PATCH 2/2] proc: use " Alexey Dobriyan
2019-05-29 22:33 ` Andrew Morton
2019-05-30 11:37 ` [PATCH 1/2] add " David Laight
2019-05-30 11:53 ` Joe Perches
2019-05-30 19:57 ` Alexey Dobriyan
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