[PATCH AUTOSEL 6.6 16/23] RDMA/siw: Add sendpage_ok() check to disable MSG_SPLICE_PAGES

[Sasha Levin]

From: Showrya M N <showrya@xxxxxxxxxxx>

[ Upstream commit 4e1e3dd88a4cedd5ccc1a3fc3d71e03b70a7a791 ]

While running ISER over SIW, the initiator machine encounters a warning
from skb_splice_from_iter() indicating that a slab page is being used in
send_page. To address this, it is better to add a sendpage_ok() check
within the driver itself, and if it returns 0, then MSG_SPLICE_PAGES flag
should be disabled before entering the network stack.

A similar issue has been discussed for NVMe in this thread:
https://lore.kernel.org/all/20240530142417.146696-1-ofir.gal@xxxxxxxxxxx/

  WARNING: CPU: 0 PID: 5342 at net/core/skbuff.c:7140 skb_splice_from_iter+0x173/0x320
  Call Trace:
   tcp_sendmsg_locked+0x368/0xe40
   siw_tx_hdt+0x695/0xa40 [siw]
   siw_qp_sq_process+0x102/0xb00 [siw]
   siw_sq_resume+0x39/0x110 [siw]
   siw_run_sq+0x74/0x160 [siw]
   kthread+0xd2/0x100
   ret_from_fork+0x34/0x40
   ret_from_fork_asm+0x1a/0x30

Link: https://patch.msgid.link/r/20241007125835.89942-1-showrya@xxxxxxxxxxx
Signed-off-by: Showrya M N <showrya@xxxxxxxxxxx>
Signed-off-by: Potnuri Bharat Teja <bharat@xxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/sw/siw/siw_qp_tx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c
index 60b6a41359611..feae920784be8 100644
--- a/drivers/infiniband/sw/siw/siw_qp_tx.c
+++ b/drivers/infiniband/sw/siw/siw_qp_tx.c
@@ -337,6 +337,8 @@ static int siw_tcp_sendpages(struct socket *s, struct page **page, int offset,
 			msg.msg_flags &= ~MSG_MORE;
 
 		tcp_rate_check_app_limited(sk);
+		if (!sendpage_ok(page[i]))
+			msg.msg_flags &= ~MSG_SPLICE_PAGES;
 		bvec_set_page(&bvec, page[i], bytes, offset);
 		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
 
-- 
2.43.0