From faa7c4eee412ca14dd6a107cb6122d31c4277cbe Mon Sep 17 00:00:00 2001 From: Pranjal Ramajor Asha Kanojiya Date: Wed, 17 May 2023 13:35:38 -0600 Subject: [PATCH] accel/qaic: Flush the transfer list again Before calling synchronize_srcu() we clear the transfer list, this is to allow all the QAIC_WAIT_BO callers to exit otherwise the system could deadlock. There could be a corner case where more elements get added to transfer list after we have flushed it. Re-flush the transfer list once all the holders of dbc->ch_lock have completed execution i.e. synchronize_srcu() is complete. Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Pranjal Ramajor Asha Kanojiya Reviewed-by: Carl Vanderlip Reviewed-by: Jeffrey Hugo Signed-off-by: Jeffrey Hugo Link: https://patchwork.freedesktop.org/patch/msgid/20230517193540.14323-4-quic_jhugo@quicinc.com --- drivers/accel/qaic/qaic_data.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e672dd244703..c1af99cfd2d1 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -1845,6 +1845,11 @@ void wakeup_dbc(struct qaic_device *qdev, u32 dbc_id) dbc->usr = NULL; empty_xfer_list(qdev, dbc); synchronize_srcu(&dbc->ch_lock); + /* + * Threads holding channel lock, may add more elements in the xfer_list. + * Flush out these elements from xfer_list. + */ + empty_xfer_list(qdev, dbc); } void release_dbc(struct qaic_device *qdev, u32 dbc_id)