[PATCH 5.4 344/348] scsi: target: cxgbit: Unmap DMA buffer before calling target_execute_cmd()

From: Greg Kroah-Hartman
Date: Mon Jul 12 2021 - 02:33:11 EST


From: Varun Prakash <varun@xxxxxxxxxxx>

commit 6ecdafaec79d4b3388a5b017245f23a0ff9d852d upstream.

Instead of calling dma_unmap_sg() after completing WRITE I/O, call
dma_unmap_sg() before calling target_execute_cmd() to sync the DMA buffer.

Link: https://lore.kernel.org/r/1618403949-3443-1-git-send-email-varun@xxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 5.4+
Signed-off-by: Varun Prakash <varun@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/target/iscsi/cxgbit/cxgbit_ddp.c | 19 ++++++++++---------
drivers/target/iscsi/cxgbit/cxgbit_target.c | 21 ++++++++++++++++++---
2 files changed, 28 insertions(+), 12 deletions(-)

--- a/drivers/target/iscsi/cxgbit/cxgbit_ddp.c
+++ b/drivers/target/iscsi/cxgbit/cxgbit_ddp.c
@@ -265,12 +265,13 @@ void cxgbit_unmap_cmd(struct iscsi_conn
struct cxgbit_cmd *ccmd = iscsit_priv_cmd(cmd);

if (ccmd->release) {
- struct cxgbi_task_tag_info *ttinfo = &ccmd->ttinfo;
-
- if (ttinfo->sgl) {
+ if (cmd->se_cmd.se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
+ put_page(sg_page(&ccmd->sg));
+ } else {
struct cxgbit_sock *csk = conn->context;
struct cxgbit_device *cdev = csk->com.cdev;
struct cxgbi_ppm *ppm = cdev2ppm(cdev);
+ struct cxgbi_task_tag_info *ttinfo = &ccmd->ttinfo;

/* Abort the TCP conn if DDP is not complete to
* avoid any possibility of DDP after freeing
@@ -280,14 +281,14 @@ void cxgbit_unmap_cmd(struct iscsi_conn
cmd->se_cmd.data_length))
cxgbit_abort_conn(csk);

+ if (unlikely(ttinfo->sgl)) {
+ dma_unmap_sg(&ppm->pdev->dev, ttinfo->sgl,
+ ttinfo->nents, DMA_FROM_DEVICE);
+ ttinfo->nents = 0;
+ ttinfo->sgl = NULL;
+ }
cxgbi_ppm_ppod_release(ppm, ttinfo->idx);
-
- dma_unmap_sg(&ppm->pdev->dev, ttinfo->sgl,
- ttinfo->nents, DMA_FROM_DEVICE);
- } else {
- put_page(sg_page(&ccmd->sg));
}
-
ccmd->release = false;
}
}
--- a/drivers/target/iscsi/cxgbit/cxgbit_target.c
+++ b/drivers/target/iscsi/cxgbit/cxgbit_target.c
@@ -1013,17 +1013,18 @@ static int cxgbit_handle_iscsi_dataout(s
struct scatterlist *sg_start;
struct iscsi_conn *conn = csk->conn;
struct iscsi_cmd *cmd = NULL;
+ struct cxgbit_cmd *ccmd;
+ struct cxgbi_task_tag_info *ttinfo;
struct cxgbit_lro_pdu_cb *pdu_cb = cxgbit_rx_pdu_cb(csk->skb);
struct iscsi_data *hdr = (struct iscsi_data *)pdu_cb->hdr;
u32 data_offset = be32_to_cpu(hdr->offset);
- u32 data_len = pdu_cb->dlen;
+ u32 data_len = ntoh24(hdr->dlength);
int rc, sg_nents, sg_off;
bool dcrc_err = false;

if (pdu_cb->flags & PDUCBF_RX_DDP_CMP) {
u32 offset = be32_to_cpu(hdr->offset);
u32 ddp_data_len;
- u32 payload_length = ntoh24(hdr->dlength);
bool success = false;

cmd = iscsit_find_cmd_from_itt_or_dump(conn, hdr->itt, 0);
@@ -1038,7 +1039,7 @@ static int cxgbit_handle_iscsi_dataout(s
cmd->data_sn = be32_to_cpu(hdr->datasn);

rc = __iscsit_check_dataout_hdr(conn, (unsigned char *)hdr,
- cmd, payload_length, &success);
+ cmd, data_len, &success);
if (rc < 0)
return rc;
else if (!success)
@@ -1076,6 +1077,20 @@ static int cxgbit_handle_iscsi_dataout(s
cxgbit_skb_copy_to_sg(csk->skb, sg_start, sg_nents, skip);
}

+ ccmd = iscsit_priv_cmd(cmd);
+ ttinfo = &ccmd->ttinfo;
+
+ if (ccmd->release && ttinfo->sgl &&
+ (cmd->se_cmd.data_length == (cmd->write_data_done + data_len))) {
+ struct cxgbit_device *cdev = csk->com.cdev;
+ struct cxgbi_ppm *ppm = cdev2ppm(cdev);
+
+ dma_unmap_sg(&ppm->pdev->dev, ttinfo->sgl, ttinfo->nents,
+ DMA_FROM_DEVICE);
+ ttinfo->nents = 0;
+ ttinfo->sgl = NULL;
+ }
+
check_payload:

rc = iscsit_check_dataout_payload(cmd, hdr, dcrc_err);