| Since the old definition is not used in the way before(x, y)
!before(y, x), but rather in the
| fashion before(x, y) or after(y, x), the main advantage of the new
definition is that it makes
| this type of use a safe case.
|
| This is not true because
|
| if (before(x, y))
|
| The key point where the new definition differs from the old is that _the
relation_
| before(x,y) is unambiguous: the case before(x,y) before(y,x) will no
longer occur.
|
| This is highly dependent on how the before macro is used in actual code.
| There is nothing to suggest that this
On Fri, Jan 05, 2007 at 11:51:16AM +, Gerrit Renker wrote:
| 2) Change before/after such that before(x, x+2^31) == !before(x+2^31, x).
This is what the new definition does: in the old definition we always have
that
before(x, x+2^31) == before(x+2^31, x).
Sorry but the new
Quoting Herbert Xu:
| On Fri, Jan 05, 2007 at 11:51:16AM +, Gerrit Renker wrote:
|
| | 2) Change before/after such that before(x, x+2^31) == !before(x+2^31,
x).
| This is what the new definition does: in the old definition we always have
that
| before(x, x+2^31) ==
| With the implementation now, the output of before(x,y) is reliable: it
returns true
| if (and only if) x is indeed `before' y.
|
| Sorry but I don't think you've answered my question.
|
| Let y = (x + 2^31) % 2^32, how is making
|
| before(x, y) == before(y, x) == 0
|
| any
On Thu, Jan 04, 2007 at 12:49:02PM +, Gerrit Renker wrote:
The key point where the new definition differs from the old is that _the
relation_
before(x,y) is unambiguous: the case before(x,y) before(y,x) will no
longer occur.
This is highly dependent on how the before macro is used in
Hi Herbert,
| While looking at DCCP sequence numbers, I stumbled over a problem with
| the following definition of before in tcp.h:
|
| static inline int before(__u32 seq1, __u32 seq2)
| {
| return (__s32)(seq1-seq2) 0;
| }
|
| Problem: This definition suffers from
Gerrit Renker [EMAIL PROTECTED] wrote:
| Prior to the patch, we have values x and y such that both
| before(x, y) and before(y, x) are true. Now for those same
| values both before(x, y) and before(y, x) are false.
|
| It's still as ambiguous as ever. Surely to resolve the
|
Hi David,
many thanks for taking the matter seriously and investigating
it further.
| I went over this patch and analysis a dozen times, because I
| couldn't believe something like this has been broken for
| so long :-)
It gave me some grief too, when I looked at DCCP sequence numbers %-)
David Miller [EMAIL PROTECTED] wrote:
From: Gerrit Renker [EMAIL PROTECTED]
Date: Thu, 14 Dec 2006 15:07:06 +
While looking at DCCP sequence numbers, I stumbled over a problem with
the following definition of before in tcp.h:
static inline int before(__u32 seq1, __u32 seq2)
{
From: Gerrit Renker [EMAIL PROTECTED]
Date: Thu, 14 Dec 2006 15:07:06 +
While looking at DCCP sequence numbers, I stumbled over a problem with
the following definition of before in tcp.h:
static inline int before(__u32 seq1, __u32 seq2)
{
return (__s32)(seq1-seq2) 0;
}
On Thu, Dec 14, 2006 at 03:07:06PM +, Gerrit Renker wrote:
diff --git a/include/net/tcp.h b/include/net/tcp.h
index c99774f..b7d8317 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -242,14 +242,9 @@ extern int tcp_memory_pressure;
static inline int before(__u32 seq1, __u32
While looking at DCCP sequence numbers, I stumbled over a problem with
the following definition of before in tcp.h:
static inline int before(__u32 seq1, __u32 seq2)
{
return (__s32)(seq1-seq2) 0;
}
Problem: This definition suffers from an an ambiguity, i.e. always
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