On Tue, Feb 21, 2023 at 08:54:00AM -0800, Keith Busch wrote:
> From: Keith Busch <kbusch@xxxxxxxxxx>
>
> Some users of the dmapool need their allocations to happen in ascending
> order. The recent optimizations pushed the blocks in reverse order, so
> restore the previous behavior by linking the next available block from
> low-to-high.
>
> Fixes: ced6d06a81fb69 ("dmapool: link blocks across pages")
> Reported-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
This patch fixes the problem I had observed when trying to boot from
the megasas SCSI controller on powernv.
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Thanks,
Guenter
> ---
> mm/dmapool.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/mm/dmapool.c b/mm/dmapool.c
> index 1920890ff8d3d..a151a21e571b7 100644
> --- a/mm/dmapool.c
> +++ b/mm/dmapool.c
> @@ -300,7 +300,7 @@ EXPORT_SYMBOL(dma_pool_create);
> static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
> {
> unsigned int next_boundary = pool->boundary, offset = 0;
> - struct dma_block *block;
> + struct dma_block *block, *first = NULL, *last = NULL;
>
> pool_init_page(pool, page);
> while (offset + pool->size <= pool->allocation) {
> @@ -311,11 +311,22 @@ static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
> }
>
> block = page->vaddr + offset;
> - pool_block_push(pool, block, page->dma + offset);
> + block->dma = page->dma + offset;
> + block->next_block = NULL;
> +
> + if (last)
> + last->next_block = block;
> + else
> + first = block;
> + last = block;
> +
> offset += pool->size;
> pool->nr_blocks++;
> }
>
> + last->next_block = pool->next_block;
> + pool->next_block = first;
> +
> list_add(&page->page_list, &pool->page_list);
> pool->nr_pages++;
> }
> --
> 2.30.2
>
>
