Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 14 May 2003 15:35:24 +0300 | From | Muli Ben-Yehuda <> | Subject | Re: [PATCH] PAG support only |
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On Wed, May 14, 2003 at 10:54:36AM +0100, David Howells wrote: > > Muli Ben-Yehuda wrote: > > > > + * VFS session authentication token cache > > ... > > > > If you know the type of the data, why keep it all in one binary blob, > > instead of a struct? cache effects? > > No. We _don't_ know the type of the data. A filesystem entrusts us with a > token to keep in the PAG on its behalf. However, since this is meant to be a > generic mechanism, it's entirely dependent on the fs as to what's in > the blob.
But you do know the type of the data in the blob... it's char* fsname, const void* key and const void* data, according to your code.
You do
void* blob = kmalloc(fsname size + key size + data size)
memcpy(blob, fsname, fsname size) memcpy(blob + fsname offset, key, key size) mempcy(blob + fsname offset + key offset, data, data size)
I suggest
struct fsblob { const char* fsname; const void* key; size_t keysize; const void* data; size_t datasize; };
struct fsblob b;
b->fsname = kmalloc(fsname size) memcpy(b->fsname, fsname, fsname size)
etc.
Your method loses on additional complexity, and wins on speed. However, unless it's really, really speed sensitive code, I would go for KISS any day.
> > Nothing in this patch appears to be using it. You aren't taking a > > reference to the token here, what's protecting it from disappearing > > after the return and before the caller gets a chance to do something > > with it? > > Thanks. Fixed.
My pleasure. -- Muli Ben-Yehuda http://www.mulix.org
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