Re: [TOMOYO #14 (mmotm 2008-12-30-16-05) 02/10] Singly linked listimplementation.

[James Morris]

On Tue, 6 Jan 2009, Tetsuo Handa wrote:

> 
> James Morris wrote:
> > This has a technical ack from Paul, but what about Linus' long-standing 
> > objection to singly-linked lists in the kernel?  I'm sure this has been 
> > discussed re. your patches, but I can't find a reference.
> I couldn't find one neither. (What does "re." mean?)

http://en.wiktionary.org/wiki/re#Etymology_1

> But optimistically speaking, there are many in-tree users who define "struct"
> without "prev" pointer.
> 
>   # grep -hr 'struct [a-zA-Z0-9_]* \*next;' linux-2.6.28/include/linux/ | wc -l
>   42
>   # grep -hr 'struct [a-zA-Z0-9_]* \*prev;' linux-2.6.28/include/linux/ | wc -l
>   7
> 
> Not all structures listed below are used as singly linked list,
> but many of them are used as singly linked list.

Can any of these be converted to your singly linked list implementation ?

> 
>   struct sched_class;
>   struct acpi_pci_driver;
>   struct adb_request;
>   struct atalk_route;
>   struct core_thread;
>   struct dma_async_tx_descriptor;
>   struct erase_info;
>   struct esp_pio_buffer;
>   struct fdtable;
>   struct floppy_raw_cmd;
>   struct ftrace_ops;
>   struct hdlc_proto;
>   struct hwif_s;
>   struct ippp_buf_queue;
>   struct irqaction;
>   struct isdn_net_local_s;
>   struct kcore_list;
>   struct mfc6_cache;
>   struct mfc_cache;
>   struct nls_table;
>   struct notifier_block;
>   struct page_list;
>   struct pbe;
>   struct phone_device;
>   struct pnp_id;
>   struct r3964_block_header;
>   struct r3964_client_info;
>   struct r3964_message;
>   struct rcu_head;
>   struct resource_list;
>   struct sched_group;
>   struct sdio_func_tuple;
>   struct tasklet_struct;
>   struct tty_buffer;
>   struct xor_block_template;
> 
> Thus, I believe it is acceptable that TOMOYO uses singly linked list
> unless Linus comes out and yell "No!".

He's yelled no in the past, so there needs to be a convincing argument 
which he'll accept.


- James
-- 
James Morris
<jmorris@xxxxxxxxx>
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