Re: [PATCH for-rc v2] RDMA/siw: add sendpage_ok() check to disable MSG_SPLICE_PAGES

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Oct 07, 2024 at 06:28:36PM +0530, Showrya M N wrote:
> 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/
> 
> stack trace:
> ...
> [ 2157.532917] WARNING: CPU: 0 PID: 5342 at net/core/skbuff.c:7140 skb_splice_from_iter+0x173/0x320
> Call Trace:
> [ 2157.533064] Call Trace:
> [ 2157.533069]  ? __warn+0x84/0x130
> [ 2157.533073]  ? skb_splice_from_iter+0x173/0x320
> [ 2157.533075]  ? report_bug+0xfc/0x1e0
> [ 2157.533081]  ? handle_bug+0x3f/0x70
> [ 2157.533085]  ? exc_invalid_op+0x17/0x70
> [ 2157.533088]  ? asm_exc_invalid_op+0x1a/0x20
> [ 2157.533096]  ? skb_splice_from_iter+0x173/0x320
> [ 2157.533101]  tcp_sendmsg_locked+0x368/0xe40
> [ 2157.533111]  siw_tx_hdt+0x695/0xa40 [siw]
> [ 2157.533134]  ? sched_balance_find_src_group+0x44/0x4f0
> [ 2157.533143]  ? __update_load_avg_cfs_rq+0x272/0x300
> [ 2157.533152]  ? place_entity+0x19/0xf0
> [ 2157.533157]  ? enqueue_entity+0xdb/0x3d0
> [ 2157.533162]  ? pick_eevdf+0xe2/0x120
> [ 2157.533169]  ? check_preempt_wakeup_fair+0x161/0x1f0
> [ 2157.533174]  ? wakeup_preempt+0x61/0x70
> [ 2157.533177]  ? ttwu_do_activate+0x5d/0x1e0
> [ 2157.533183]  ? try_to_wake_up+0x78/0x610
> [ 2157.533188]  ? xas_load+0xd/0xb0
> [ 2157.533193]  ? xa_load+0x80/0xb0
> [ 2157.533200]  siw_qp_sq_process+0x102/0xb00 [siw]
> [ 2157.533213]  ? __pfx_siw_run_sq+0x10/0x10 [siw]
> [ 2157.533224]  siw_sq_resume+0x39/0x110 [siw]
> [ 2157.533236]  siw_run_sq+0x74/0x160 [siw]
> [ 2157.533246]  ? __pfx_autoremove_wake_function+0x10/0x10
> [ 2157.533252]  kthread+0xd2/0x100
> [ 2157.533257]  ? __pfx_kthread+0x10/0x10
> [ 2157.533261]  ret_from_fork+0x34/0x40
> [ 2157.533266]  ? __pfx_kthread+0x10/0x10
> [ 2157.533269]  ret_from_fork_asm+0x1a/0x30
> .
> [ 2157.533301] iser: iser_qp_event_callback: qp event QP request error (2)
> [ 2157.533307] iser: iser_qp_event_callback: qp event send queue drained (5)
> [ 2157.533348]  connection26:0: detected conn error (1011)
> 
> Signed-off-by: Showrya M N <showrya@chelsio.com>
> Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
> ---
> V1 -> V2: addressed review comment
> https://lore.kernel.org/all/BN8PR15MB2513C8CC78CBEADA83117A5599712@BN8PR15MB2513.namprd15.prod.outlook.com/
> ---
> 
>  drivers/infiniband/sw/siw/siw_qp_tx.c | 2 ++
>  1 file changed, 2 insertions(+)

Applied to for-rc, thanks

Jason