[PATCH net] gve: Do not fully free QPL pages on prefill errors

[PATCH net] gve: Do not fully free QPL pages on prefill errors

[Shailend Chand]

The prefill function should have only removed the page count bias it
added. Fully freeing the page will cause gve_free_queue_page_list to
free a page the driver no longer owns.

Fixes: 82fd151d38d9 ("gve: Reduce alloc and copy costs in the GQ rx path")
Signed-off-by: Shailend Chand <shailend@google.com>
---
 drivers/net/ethernet/google/gve/gve_rx.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
index d1da7413dc4d..e84a066aa1a4 100644
--- a/drivers/net/ethernet/google/gve/gve_rx.c
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -146,7 +146,7 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
 		err = gve_rx_alloc_buffer(priv, &priv->pdev->dev, &rx->data.page_info[i],
 					  &rx->data.data_ring[i]);
 		if (err)
-			goto alloc_err;
+			goto alloc_err_rda;
 	}
 
 	if (!rx->data.raw_addressing) {
@@ -171,12 +171,26 @@ static int gve_prefill_rx_pages(struct gve_rx_ring *rx)
 	return slots;
 
 alloc_err_qpl:
+	/* Fully free the copy pool pages. */
 	while (j--) {
 		page_ref_sub(rx->qpl_copy_pool[j].page,
 			     rx->qpl_copy_pool[j].pagecnt_bias - 1);
 		put_page(rx->qpl_copy_pool[j].page);
 	}
-alloc_err:
+
+	/* Do not fully free QPL pages - only remove the bias added in this
+	 * function with gve_setup_rx_buffer.
+	 */
+	while (i--)
+		page_ref_sub(rx->data.page_info[i].page,
+			     rx->data.page_info[i].pagecnt_bias - 1);
+
+	gve_unassign_qpl(priv, rx->data.qpl->id);
+	rx->data.qpl = NULL;
+
+	return err;
+
+alloc_err_rda:
 	while (i--)
 		gve_rx_free_buffer(&priv->pdev->dev,
 				   &rx->data.page_info[i],
-- 
2.42.0.655.g421f12c284-goog

Re: [PATCH net] gve: Do not fully free QPL pages on prefill errors

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Sat, 14 Oct 2023 01:41:21 +0000 you wrote:
> The prefill function should have only removed the page count bias it
> added. Fully freeing the page will cause gve_free_queue_page_list to
> free a page the driver no longer owns.
> 
> Fixes: 82fd151d38d9 ("gve: Reduce alloc and copy costs in the GQ rx path")
> Signed-off-by: Shailend Chand <shailend@google.com>
> 
> [...]

Here is the summary with links:
  - [net] gve: Do not fully free QPL pages on prefill errors
    https://git.kernel.org/netdev/net/c/95535e37e895

You are awesome, thank you!
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