On Mon, Feb 10, 2014 at 01:52:56PM +0200, Rakesh Pandit wrote:
You're missing a commit message here providing justification for the changes
submitted. Why is this change a good thing? Did it fix any bugs?
-ben
> Signed-off-by: Rakesh Pandit <rakesh@xxxxxxxxxx>
> ---
> fs/aio.c | 55 +++++++++++++++++++++++--------------------------------
> 1 file changed, 23 insertions(+), 32 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index d3d55dc..20d690a 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -278,32 +278,46 @@ static int aio_set_page_dirty(struct page *page)
> }
>
> #if IS_ENABLED(CONFIG_MIGRATION)
> -static int aio_migratepage(struct address_space *mapping, struct page *new,
> - struct page *old, enum migrate_mode mode)
> +static int aio_migratepage_helper(struct address_space *mapping,
> + struct page *new, struct page *old, bool move)
> {
> struct kioctx *ctx;
> unsigned long flags;
> - int rc;
> -
> - rc = 0;
> + int rc = 0;
>
> - /* Make sure the old page hasn't already been changed */
> + /* We can potentially race against kioctx teardown here. Use the
> + * address_space's private data lock to protect the mapping's
> + * private_data.
> + */
> spin_lock(&mapping->private_lock);
> ctx = mapping->private_data;
> if (ctx) {
> pgoff_t idx;
> spin_lock_irqsave(&ctx->completion_lock, flags);
> + if (move)
> + migrate_page_copy(new, old);
> idx = old->index;
> if (idx < (pgoff_t)ctx->nr_pages) {
> if (ctx->ring_pages[idx] != old)
> rc = -EAGAIN;
> + else if (move)
> + ctx->ring_pages[idx] = new;
> } else
> rc = -EINVAL;
> spin_unlock_irqrestore(&ctx->completion_lock, flags);
> } else
> - rc = -EINVAL;
> + rc = move ? -EBUSY : -EINVAL;
> spin_unlock(&mapping->private_lock);
> + return rc;
> +}
>
> +static int aio_migratepage(struct address_space *mapping, struct page *new,
> + struct page *old, enum migrate_mode mode)
> +{
> + int rc = 0;
> +
> + /* Make sure the old page hasn't already been changed */
> + rc = aio_migratepage_helper(mapping, new, old, false);
> if (rc != 0)
> return rc;
>
> @@ -317,31 +331,8 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
> return rc;
> }
>
> - /* We can potentially race against kioctx teardown here. Use the
> - * address_space's private data lock to protect the mapping's
> - * private_data.
> - */
> - spin_lock(&mapping->private_lock);
> - ctx = mapping->private_data;
> - if (ctx) {
> - pgoff_t idx;
> - spin_lock_irqsave(&ctx->completion_lock, flags);
> - migrate_page_copy(new, old);
> - idx = old->index;
> - if (idx < (pgoff_t)ctx->nr_pages) {
> - /* And only do the move if things haven't changed */
> - if (ctx->ring_pages[idx] == old)
> - ctx->ring_pages[idx] = new;
> - else
> - rc = -EAGAIN;
> - } else
> - rc = -EINVAL;
> - spin_unlock_irqrestore(&ctx->completion_lock, flags);
> - } else
> - rc = -EBUSY;
> - spin_unlock(&mapping->private_lock);
> -
> - if (rc == MIGRATEPAGE_SUCCESS)
> + rc = aio_migratepage_helper(mapping, new, old, true);
> + if (rc == 0)
> put_page(old);
> else
> put_page(new);
> --
> 1.8.3.1
--
"Thought is the essence of where you are now."
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