Re: [FSAIO][PATCH 7/8] Filesystem AIO read

From: Christoph Hellwig
Date: Thu Dec 28 2006 - 06:58:13 EST

> + if (in_aio()) {
> + /* Avoid repeat readahead */
> + if (kiocbTryRestart(io_wait_to_kiocb(current->io_wait)))
> + next_index = last_index;
> + }

Every place we use kiocbTryRestart in this and the next patch it's in
this from, so we should add a little helper for it:

int aio_try_restart(void)
struct wait_queue_head_t *wq = current->io_wait;

if (!is_sync_wait(wq) && kiocbTryRestart(io_wait_to_kiocb(wq)))
return 1;
return 0;

with a big kerneldoc comment explaining this idiom (and possible a better
name for the function ;-))

> +
> + if ((error = __lock_page(page, current->io_wait))) {
> + goto readpage_error;
> + }

This should be

error = __lock_page(page, current->io_wait);
if (error)
goto readpage_error;

Pluse possible naming updates discussed in the last mail. Also do we
really need to pass current->io_wait here? Isn't the waitqueue in
the kiocb always guaranteed to be the same? Now that all pagecache
I/O goes through the ->aio_read/->aio_write routines I'd prefer to
get rid of the task_struct field cludges and pass all this around in
the kiocb.

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