* [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable
@ 2024-01-16 14:09 Nathan Lynch via B4 Relay
2024-01-16 19:40 ` Christophe JAILLET
2024-01-17 14:32 ` Steven Rostedt
0 siblings, 2 replies; 5+ messages in thread
From: Nathan Lynch via B4 Relay @ 2024-01-16 14:09 UTC (permalink / raw)
To: Steven Rostedt (Google), Kees Cook; +Cc: linux-kernel, Nathan Lynch
From: Nathan Lynch <nathanl@linux.ibm.com>
Using the address operator on the array doesn't work:
./include/linux/seq_buf.h:27:27: error: initialization of ‘char *’
from incompatible pointer type ‘char (*)[128]’
[-Werror=incompatible-pointer-types]
27 | .buffer = &__ ## NAME ## _buffer, \
| ^
Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a
compound literal to define the buffer array without attaching a name
to it. This makes the macro a single statement, allowing constructs
such as:
static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
to work as intended.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()")
---
include/linux/seq_buf.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 5fb1f12c33f9..c44f4b47b945 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -22,9 +22,8 @@ struct seq_buf {
};
#define DECLARE_SEQ_BUF(NAME, SIZE) \
- char __ ## NAME ## _buffer[SIZE] = ""; \
struct seq_buf NAME = { \
- .buffer = &__ ## NAME ## _buffer, \
+ .buffer = (char[SIZE]) { 0 }, \
.size = SIZE, \
}
---
base-commit: 70d201a40823acba23899342d62bc2644051ad2e
change-id: 20240112-declare-seq-buf-fix-9803b7e679bc
Best regards,
--
Nathan Lynch <nathanl@linux.ibm.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable
2024-01-16 14:09 [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable Nathan Lynch via B4 Relay
@ 2024-01-16 19:40 ` Christophe JAILLET
2024-01-16 20:09 ` Steven Rostedt
2024-01-17 14:32 ` Steven Rostedt
1 sibling, 1 reply; 5+ messages in thread
From: Christophe JAILLET @ 2024-01-16 19:40 UTC (permalink / raw)
To: nathanl, Steven Rostedt (Google), Kees Cook; +Cc: linux-kernel
Le 16/01/2024 à 15:09, Nathan Lynch via B4 Relay a écrit :
> From: Nathan Lynch <nathanl@linux.ibm.com>
>
> Using the address operator on the array doesn't work:
>
> /include/linux/seq_buf.h:27:27: error: initialization of ‘char *’
> from incompatible pointer type ‘char (*)[128]’
> [-Werror=incompatible-pointer-types]
> 27 | .buffer = &__ ## NAME ## _buffer, \
> | ^
>
> Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a
> compound literal to define the buffer array without attaching a name
> to it. This makes the macro a single statement, allowing constructs
> such as:
>
> static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
>
> to work as intended.
>
> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
> Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()")
> ---
> include/linux/seq_buf.h | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 5fb1f12c33f9..c44f4b47b945 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -22,9 +22,8 @@ struct seq_buf {
> };
>
> #define DECLARE_SEQ_BUF(NAME, SIZE) \
> - char __ ## NAME ## _buffer[SIZE] = ""; \
> struct seq_buf NAME = { \
> - .buffer = &__ ## NAME ## _buffer, \
> + .buffer = (char[SIZE]) { 0 }, \
> .size = SIZE, \
> }
Hi,
just removing the & in ".buffer = __ ## NAME ## _buffer, \" also works IIRC.
See [1], which unfortunately has been unnoticed.
CJ
[1]:
https://lore.kernel.org/all/2a534333-b5f6-4b1d-b4b8-a1a71f91c3ff@wanadoo.fr/
>
>
> ---
> base-commit: 70d201a40823acba23899342d62bc2644051ad2e
> change-id: 20240112-declare-seq-buf-fix-9803b7e679bc
>
> Best regards,
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable
2024-01-16 19:40 ` Christophe JAILLET
@ 2024-01-16 20:09 ` Steven Rostedt
0 siblings, 0 replies; 5+ messages in thread
From: Steven Rostedt @ 2024-01-16 20:09 UTC (permalink / raw)
To: Christophe JAILLET; +Cc: nathanl, Kees Cook, linux-kernel
On Tue, 16 Jan 2024 20:40:29 +0100
Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote:
> Le 16/01/2024 à 15:09, Nathan Lynch via B4 Relay a écrit :
> > From: Nathan Lynch <nathanl@linux.ibm.com>
> >
> > Using the address operator on the array doesn't work:
> >
> > /include/linux/seq_buf.h:27:27: error: initialization of ‘char *’
> > from incompatible pointer type ‘char (*)[128]’
> > [-Werror=incompatible-pointer-types]
> > 27 | .buffer = &__ ## NAME ## _buffer, \
> > | ^
> >
> > Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a
> > compound literal to define the buffer array without attaching a name
> > to it. This makes the macro a single statement, allowing constructs
> > such as:
> >
> > static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
> >
> > to work as intended.
> >
> > Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
> > Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()")
> > ---
> > include/linux/seq_buf.h | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> > index 5fb1f12c33f9..c44f4b47b945 100644
> > --- a/include/linux/seq_buf.h
> > +++ b/include/linux/seq_buf.h
> > @@ -22,9 +22,8 @@ struct seq_buf {
> > };
> >
> > #define DECLARE_SEQ_BUF(NAME, SIZE) \
> > - char __ ## NAME ## _buffer[SIZE] = ""; \
> > struct seq_buf NAME = { \
> > - .buffer = &__ ## NAME ## _buffer, \
> > + .buffer = (char[SIZE]) { 0 }, \
> > .size = SIZE, \
> > }
>
> Hi,
>
> just removing the & in ".buffer = __ ## NAME ## _buffer, \" also works IIRC.
>
> See [1], which unfortunately has been unnoticed.
>
> CJ
>
>
> [1]:
> https://lore.kernel.org/all/2a534333-b5f6-4b1d-b4b8-a1a71f91c3ff@wanadoo.fr/
I guess I missed that.
But it still doesn't fix this case:
static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
Which this patch does.
-- Steve
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable
2024-01-16 14:09 [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable Nathan Lynch via B4 Relay
2024-01-16 19:40 ` Christophe JAILLET
@ 2024-01-17 14:32 ` Steven Rostedt
2024-01-17 20:29 ` Kees Cook
1 sibling, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2024-01-17 14:32 UTC (permalink / raw)
To: Nathan Lynch via B4 Relay; +Cc: nathanl, Kees Cook, linux-kernel
Kees,
Are you OK with this change? I ran it through my tests and have another
pull request ready to go that includes this. But I don't want to send it
without an Acked-by from you.
Luckily, Linus is on non-voluntary vacation so we may still have time ;-)
-- Steve
On Tue, 16 Jan 2024 08:09:25 -0600
Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org> wrote:
> From: Nathan Lynch <nathanl@linux.ibm.com>
>
> Using the address operator on the array doesn't work:
>
> ./include/linux/seq_buf.h:27:27: error: initialization of ‘char *’
> from incompatible pointer type ‘char (*)[128]’
> [-Werror=incompatible-pointer-types]
> 27 | .buffer = &__ ## NAME ## _buffer, \
> | ^
>
> Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a
> compound literal to define the buffer array without attaching a name
> to it. This makes the macro a single statement, allowing constructs
> such as:
>
> static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
>
> to work as intended.
>
> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
> Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()")
> ---
> include/linux/seq_buf.h | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index 5fb1f12c33f9..c44f4b47b945 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -22,9 +22,8 @@ struct seq_buf {
> };
>
> #define DECLARE_SEQ_BUF(NAME, SIZE) \
> - char __ ## NAME ## _buffer[SIZE] = ""; \
> struct seq_buf NAME = { \
> - .buffer = &__ ## NAME ## _buffer, \
> + .buffer = (char[SIZE]) { 0 }, \
> .size = SIZE, \
> }
>
>
> ---
> base-commit: 70d201a40823acba23899342d62bc2644051ad2e
> change-id: 20240112-declare-seq-buf-fix-9803b7e679bc
>
> Best regards,
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable
2024-01-17 14:32 ` Steven Rostedt
@ 2024-01-17 20:29 ` Kees Cook
0 siblings, 0 replies; 5+ messages in thread
From: Kees Cook @ 2024-01-17 20:29 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Nathan Lynch via B4 Relay, nathanl, linux-kernel
On Wed, Jan 17, 2024 at 09:32:34AM -0500, Steven Rostedt wrote:
>
> Kees,
>
> Are you OK with this change? I ran it through my tests and have another
> pull request ready to go that includes this. But I don't want to send it
> without an Acked-by from you.
Yeah! This cleanly solves the lack of being able to add the "static",
etc.
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
>
> Luckily, Linus is on non-voluntary vacation so we may still have time ;-)
>
> -- Steve
>
>
> On Tue, 16 Jan 2024 08:09:25 -0600
> Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org> wrote:
>
> > From: Nathan Lynch <nathanl@linux.ibm.com>
> >
> > Using the address operator on the array doesn't work:
> >
> > ./include/linux/seq_buf.h:27:27: error: initialization of ‘char *’
> > from incompatible pointer type ‘char (*)[128]’
> > [-Werror=incompatible-pointer-types]
> > 27 | .buffer = &__ ## NAME ## _buffer, \
> > | ^
> >
> > Apart from fixing that, we can improve DECLARE_SEQ_BUF() by using a
> > compound literal to define the buffer array without attaching a name
> > to it. This makes the macro a single statement, allowing constructs
> > such as:
> >
> > static DECLARE_SEQ_BUF(my_seq_buf, MYSB_SIZE);
> >
> > to work as intended.
> >
> > Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
> > Fixes: dcc4e5728eea ("seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()")
> > ---
> > include/linux/seq_buf.h | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> > index 5fb1f12c33f9..c44f4b47b945 100644
> > --- a/include/linux/seq_buf.h
> > +++ b/include/linux/seq_buf.h
> > @@ -22,9 +22,8 @@ struct seq_buf {
> > };
> >
> > #define DECLARE_SEQ_BUF(NAME, SIZE) \
> > - char __ ## NAME ## _buffer[SIZE] = ""; \
> > struct seq_buf NAME = { \
> > - .buffer = &__ ## NAME ## _buffer, \
> > + .buffer = (char[SIZE]) { 0 }, \
> > .size = SIZE, \
> > }
> >
> >
> > ---
> > base-commit: 70d201a40823acba23899342d62bc2644051ad2e
> > change-id: 20240112-declare-seq-buf-fix-9803b7e679bc
> >
> > Best regards,
>
--
Kees Cook
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2024-01-17 20:29 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2024-01-16 14:09 [PATCH] seq_buf: make DECLARE_SEQ_BUF() usable Nathan Lynch via B4 Relay
2024-01-16 19:40 ` Christophe JAILLET
2024-01-16 20:09 ` Steven Rostedt
2024-01-17 14:32 ` Steven Rostedt
2024-01-17 20:29 ` Kees Cook
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