5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Koichiro Den <redacted>
commit 256496397287334a19ed80ec7be92bffcae76b9d upstream.
ntb_tx_copy_callback() invokes the client callback before returning the
entry to tx_free_q. The callback may wake a stopped client queue, only
for the next enqueue to find no local entry and return -EBUSY. The window
is narrow, but the retry is unnecessary.
Save the callback data and length, then return the entry to tx_free_q
before invoking the client. A completion callback then means both the
client buffer and transport entry are ready for reuse.
Fixes: fce8a7bb5b4b ("PCI-Express Non-Transparent Bridge Support")
Cc: <redacted>
Signed-off-by: Koichiro Den <redacted>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260817053519.4135287-2-den@valinux.co.jp (local)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/ntb/ntb_transport.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1732,9 +1732,16 @@ static void ntb_transport_rxc_db(unsigne
static void ntb_tx_copy_callback(void *data,
const struct dmaengine_result *res)
{
+ struct ntb_payload_header __iomem *hdr;
struct ntb_queue_entry *entry = data;
- struct ntb_transport_qp *qp = entry->qp;
- struct ntb_payload_header __iomem *hdr = entry->tx_hdr;
+ struct ntb_transport_qp *qp;
+ unsigned int len;
+ void *cb_data;
+
+ qp = entry->qp;
+ hdr = entry->tx_hdr;
+ cb_data = entry->cb_data;
+ len = entry->len;
/* we need to check DMA results if we are using DMA */
if (res) {@@ -1774,15 +1781,13 @@ static void ntb_tx_copy_callback(void *d
* "link down" or similar. Since no payload is being sent in these
* cases, there is nothing to add to the completion queue.
*/
- if (entry->len > 0) {
- qp->tx_bytes += entry->len;
-
- if (qp->tx_handler)
- qp->tx_handler(qp, qp->cb_data, entry->cb_data,
- entry->len);
- }
+ if (len > 0)
+ qp->tx_bytes += len;
ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q);
+
+ if (len > 0 && qp->tx_handler)
+ qp->tx_handler(qp, qp->cb_data, cb_data, len);
}
static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset)