lkml.org 
[lkml]   [2007]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 1/4] Linux Kernel Markers - Architecture Independent Code
* Rusty Russell (rusty@rustcorp.com.au) wrote:
> On Fri, 2007-08-24 at 12:26 -0400, Mathieu Desnoyers wrote:
> > * Rusty Russell (rusty@rustcorp.com.au) wrote:
> > > On Mon, 2007-08-20 at 16:27 -0400, Mathieu Desnoyers wrote:
> > > > +{
> > > > + struct hlist_head *head;
> > > > + struct hlist_node *node;
> > > > + struct marker_entry *e;
> > > > + size_t len = strlen(name) + 1;
> > > > + u32 hash = jhash(name, len-1, 0);
> > > > +
> > > > + head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
> > > > + hlist_for_each_entry(e, node, head, hlist) {
> > > > + if (!strcmp(name, e->name))
> > > > + return e;
> > > > + }
> > > > + return NULL;
> > > > +}
> > >
> > > OK, don't understand the strlen, len, len-1 dance here?
> > >
> >
> > Let's say we have abc\0 for marker name as name input.
> >
> > len = 3 + 1 = 4 (including \0)
> > hash is done only on the 3 first chars, excluding the \0 (therefore the
> > len-1 there)
> >
> > Actually, it's like this only for a matter of consistency between
> > add_marker and remove_marker, which are quite similar, but add_marker
> > needs name_len to include the \0 value. It would be odd to change the
> > logic between the two functions to one including the \0 and the other
> > excluding it.
>
> Sure, but that doesn't really explain why the code does:
>
> size_t len = strlen(name) + 1;
> u32 hash = jhash(name, len-1, 0);
>
> Rather than:
>
> u32 hash = jhash(name, strlen(name), 0);
>

Yup, good point. Fixed.

Thanks,

Mathieu

> > Thanks for the review,
>
> That's fine, just some light reading...
>
> Cheers,
> Rusty.
> >
>

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-25 23:29    [from the cache]
©2003-2011 Jasper Spaans