6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Caleb Sander Mateos csander@purestorage.com
[ Upstream commit 8e3100fcc5cbba03518b8b5c059624aba5c29d50 ]
io_send_zc() guards its call to io_send_zc_import() with if (!done_io) in an attempt to avoid calling it redundantly on the same req. However, if the initial non-blocking issue returns -EAGAIN, done_io will stay 0. This causes the subsequent issue to unnecessarily re-import the buffer.
Add an explicit flag "imported" to io_sr_msg to track if its buffer has already been imported. Clear the flag in io_send_zc_prep(). Call io_send_zc_import() and set the flag in io_send_zc() if it is unset.
Signed-off-by: Caleb Sander Mateos csander@purestorage.com Fixes: 54cdcca05abd ("io_uring/net: switch io_send() and io_send_zc() to using io_async_msghdr") Link: https://lore.kernel.org/r/20250321184819.3847386-2-csander@purestorage.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- io_uring/net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/io_uring/net.c b/io_uring/net.c index bfdbbf0b9e90d..706a5bc75a714 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -77,6 +77,7 @@ struct io_sr_msg { u16 buf_group; u16 buf_index; bool retry; + bool imported; /* only for io_send_zc */ void __user *msg_control; /* used only for send zerocopy */ struct io_kiocb *notif; @@ -1251,6 +1252,7 @@ int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
zc->done_io = 0; zc->retry = false; + zc->imported = false; req->flags |= REQ_F_POLL_NO_LAZY;
if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3))) @@ -1413,7 +1415,8 @@ int io_send_zc(struct io_kiocb *req, unsigned int issue_flags) (zc->flags & IORING_RECVSEND_POLL_FIRST)) return -EAGAIN;
- if (!zc->done_io) { + if (!zc->imported) { + zc->imported = true; ret = io_send_zc_import(req, issue_flags); if (unlikely(ret)) return ret;