[PATCH 3.16 083/366] IB/isert: Fix for lib/dma_debug check_sync warning

Ben Hutchings
2018-11-11T20:17:37Z

From: Alex Estrin <alex.estrin@intel.com>

commit 763b69654bfb88ea3230d015e7d755ee8339f8ee upstream.

The following error message occurs on a target host in a debug build
during session login:

[ 3524.411874] WARNING: CPU: 5 PID: 12063 at lib/dma-debug.c:1207 check_sync+0x4ec/0x5b0
[ 3524.421057] infiniband hfi1_0: DMA-API: device driver tries to sync DMA memory it has not allocated [device address=0x0000000000000000] [size=76 bytes]
......snip .....

[ 3524.535846] CPU: 5 PID: 12063 Comm: iscsi_np Kdump: loaded Not tainted 3.10.0-862.el7.x86_64.debug #1
[ 3524.546764] Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 1.2.6 06/08/2015
[ 3524.555740] Call Trace:
[ 3524.559102] [<ffffffffa5fe915b>] dump_stack+0x19/0x1b
[ 3524.565477] [<ffffffffa58a2f58>] __warn+0xd8/0x100
[ 3524.571557] [<ffffffffa58a2fdf>] warn_slowpath_fmt+0x5f/0x80
[ 3524.578610] [<ffffffffa5bf5b8c>] check_sync+0x4ec/0x5b0
[ 3524.585177] [<ffffffffa58efc3f>] ? set_cpus_allowed_ptr+0x5f/0x1c0
[ 3524.592812] [<ffffffffa5bf5cd0>] debug_dma_sync_single_for_cpu+0x80/0x90
[ 3524.601029] [<ffffffffa586add3>] ? x2apic_send_IPI_mask+0x13/0x20
[ 3524.608574] [<ffffffffa585ee1b>] ? native_smp_send_reschedule+0x5b/0x80
[ 3524.616699] [<ffffffffa58e9b76>] ? resched_curr+0xf6/0x140
[ 3524.623567] [<ffffffffc0879af0>] isert_create_send_desc.isra.26+0xe0/0x110 [ib_isert]
[ 3524.633060] [<ffffffffc087af95>] isert_put_login_tx+0x55/0x8b0 [ib_isert]
[ 3524.641383] [<ffffffffa58ef114>] ? try_to_wake_up+0x1a4/0x430
[ 3524.648561] [<ffffffffc098cfed>] iscsi_target_do_tx_login_io+0xdd/0x230 [iscsi_target_mod]
[ 3524.658557] [<ffffffffc098d827>] iscsi_target_do_login+0x1a7/0x600 [iscsi_target_mod]
[ 3524.668084] [<ffffffffa59f9bc9>] ? kstrdup+0x49/0x60
[ 3524.674420] [<ffffffffc098e976>] iscsi_target_start_negotiation+0x56/0xc0 [iscsi_target_mod]
[ 3524.684656] [<ffffffffc098c2ee>] __iscsi_target_login_thread+0x90e/0x1070 [iscsi_target_mod]
[ 3524.694901] [<ffffffffc098ca50>] ? __iscsi_target_login_thread+0x1070/0x1070 [iscsi_target_mod]
[ 3524.705446] [<ffffffffc098ca50>] ? __iscsi_target_login_thread+0x1070/0x1070 [iscsi_target_mod]
[ 3524.715976] [<ffffffffc098ca78>] iscsi_target_login_thread+0x28/0x60 [iscsi_target_mod]
[ 3524.725739] [<ffffffffa58d60ff>] kthread+0xef/0x100
[ 3524.732007] [<ffffffffa58d6010>] ? insert_kthread_work+0x80/0x80
[ 3524.739540] [<ffffffffa5fff1b7>] ret_from_fork_nospec_begin+0x21/0x21
[ 3524.747558] [<ffffffffa58d6010>] ? insert_kthread_work+0x80/0x80
[ 3524.755088] ---[ end trace 23f8bf9238bd1ed8 ]---
[ 3595.510822] iSCSI/iqn.1994-05.com.redhat:537fa56299: Unsupported SCSI Opcode 0xa3, sending CHECK_CONDITION.

The code calls dma_sync on login_tx_desc->dma_addr prior to initializing it
with dma-mapped address.
login_tx_desc is a part of iser_conn structure and is used only once
during login negotiation, so the issue is fixed by eliminating
dma_sync call for this buffer using a special case routine.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Don Dutile <ddutile@redhat.com>
Signed-off-by: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.16:
- Parameters to isert_create_send_desc() are not redundant; forward them
all to __isert_create_send_desc()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/infiniband/ulp/isert/ib_isert.c | 26 ++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)

--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1033,14 +1033,10 @@ isert_post_send(struct isert_conn *isert
}

static void
-isert_create_send_desc(struct isert_conn *isert_conn,
- struct isert_cmd *isert_cmd,
- struct iser_tx_desc *tx_desc)
+__isert_create_send_desc(struct isert_conn *isert_conn,
+ struct isert_cmd *isert_cmd,
+ struct iser_tx_desc *tx_desc)
{
- struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
-
- ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
- ISER_HEADERS_LEN, DMA_TO_DEVICE);

memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
tx_desc->iser_header.flags = ISER_VER;
@@ -1054,6 +1050,19 @@ isert_create_send_desc(struct isert_conn
}
}

+static void
+isert_create_send_desc(struct isert_conn *isert_conn,
+ struct isert_cmd *isert_cmd,
+ struct iser_tx_desc *tx_desc)
+{
+ struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+
+ ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
+ ISER_HEADERS_LEN, DMA_TO_DEVICE);
+
+ __isert_create_send_desc(isert_conn, isert_cmd, tx_desc);
+}
+
static int
isert_init_tx_hdrs(struct isert_conn *isert_conn,
struct iser_tx_desc *tx_desc)
@@ -1150,7 +1159,7 @@ isert_put_login_tx(struct iscsi_conn *co
struct iser_tx_desc *tx_desc = &isert_conn->conn_login_tx_desc;
int ret;

- isert_create_send_desc(isert_conn, NULL, tx_desc);
+ __isert_create_send_desc(isert_conn, NULL, tx_desc);

memcpy(&tx_desc->iscsi_header, &login->rsp[0],
sizeof(struct iscsi_hdr));