Messages in this thread |  | | | Subject | Re: get_unused_fd() | | From | Magnus Ahltorp <> | | Date | 21 Oct 1998 01:27:36 +0200 |
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> > Does anyone have religious problems with this patch? > > I'd like to know who and why needs it..
I sent a message to the list some weeks ago (included below) and since no one has commented on that, I supposed that there were no objections.
The thing is, it's very hard to do some serious file system modules hacking without these functions. Since the Linux module system is built the way it is, symbol names have to, as you know, be explicitly exported.
This is all very good (since you get nice things like version symbols), but it relies on the fact that someone puts the EXPORT_SYMBOL lines in the kernel. Therefore, I am now proposing this patch.
The particular purpose is an open split into two parts (the lookup phase and the opening phase). Cookies are used to divide the process between two syscalls. This is used in Arla, the free AFS client from KTH.
Since the symbol has not been exported, development code must look like this:
int (* get_unused_fd_p)(void) = 0xf0043c3c;
This is what I'm trying to avoid.
/Magnus map@stacken.kth.se
--------------------------------------------------------------- From: Magnus Ahltorp <map@stacken.kth.se> Subject: get_unused_fd & get_empty_filp To: linux-kernel@vger.rutgers.edu Date: 08 Oct 1998 21:56:28 +0200 X-From-Line: nobody Thu Oct 8 21:56:32 1998 Sender: map@yakko.stacken.kth.se Message-ID: <lv1sogyakur.fsf@yakko.stacken.kth.se> X-Mailer: Gnus v5.3/Emacs 19.34 Lines: 12 Xref: yakko.stacken.kth.se sent-mail:151 X-Gnus-Article-Number: 151 Thu Oct 8 21:56:32 1998 Would it be very bad if get_unused_fd() and get_empty_filp() were exported, so that modules are able to allocate entries in the file table?
This is absolutely necessary for "half way" open system calls, that does the file name lookup in one part, and the actual opening in the second part.
/Magnus map@stacken.kth.se
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