RDMA/siw: Add sendpage_ok() check to disable MSG_SPLICE_PAGES

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Add sendpage_ok() check to disable MSG_SPLICE_PAGES 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@volumez.com/ 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

Where it's fixed