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Re: [Xen-devel] [PATCH 02/16] x86: fix: make atomic_read() param const
On 7/12/2016 3:49 PM, Andrew Cooper wrote:
On 12/07/16 11:38, Corneliu ZUZU wrote:
On 7/12/2016 1:22 PM, Andrew Cooper wrote:
On 12/07/16 11:11, Corneliu ZUZU wrote:
If you are really feeling up to it, having a common xen/atomic.h
with
typedef struct { int counter; } atomic_t;
#define ATOMIC_INIT(i) { (i) }
and some prototypes such as:
static inline int atomic_read(const atomic_t *v);
would be great, but this looks like it has the possibility to turn
into
a rats nest. If it does, then just doubling up this code for arm
is ok.
~Andrew
Yes, that might be more complicated than we expect and I don't
know if
making code such as this common would be a good idea, usually these
functions are always architecture-specific.
I only suggested making the prototype common, not the implementation.
As such, the issue you accidentally introduced would become a hard
build
failure on affected architectures, rather than a subtle build
failure in
common code at some point in the future.
~Andrew
Oh, I see, good idea, I've just tested it and it works, what did you
have in mind when you said it could cause problems?
The build issues would come at some point later when someone attempts to
atomic_read() a constant atomic_t in common code, when the ARM build
would break.
~Andrew
Ooh, no, I was asking what you meant when you said "this looks like it
has the possibility to turn into a rats nest" in your first message,
not the thing about hard build failure..
Ah. sorry.
You would have to invert all the includes of atomic.h to include
<xen/atomic.h> rather than <asm/atomic.h>, and have xen/atomic.h include
asm/atomic.h towards the end, such that the common prototypes are
first. I just suspect that this might not be completely trivial to
untangle (of course, I could also be wrong).
~Andrew
I did it the other way - included <xen/monitor.h> from <asm/monitor.h>.
Zuzu C.
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