Re: [PATCH 03/22] libiscsi: Make use of new the sg_map helper function

2017-04-14 Thread Logan Gunthorpe


On 14/04/17 02:36 AM, Christoph Hellwig wrote:
> On Thu, Apr 13, 2017 at 04:05:16PM -0600, Logan Gunthorpe wrote:
>> Convert the kmap and kmap_atomic uses to the sg_map function. We now
>> store the flags for the kmap instead of a boolean to indicate
>> atomicitiy. We also propogate a possible kmap error down and create
>> a new ISCSI_TCP_INTERNAL_ERR error type for this.
> 
> Can you split out the new error handling into a separate prep patch
> which should go to the iscsi maintainers ASAP?
> 

Yes, I can do that. I'd just have thought they'd want to see the use
case for the new error before accepting a patch like that...

Logan


Re: [PATCH 03/22] libiscsi: Make use of new the sg_map helper function

2017-04-14 Thread Christoph Hellwig
On Thu, Apr 13, 2017 at 04:05:16PM -0600, Logan Gunthorpe wrote:
> Convert the kmap and kmap_atomic uses to the sg_map function. We now
> store the flags for the kmap instead of a boolean to indicate
> atomicitiy. We also propogate a possible kmap error down and create
> a new ISCSI_TCP_INTERNAL_ERR error type for this.

Can you split out the new error handling into a separate prep patch
which should go to the iscsi maintainers ASAP?


[PATCH 03/22] libiscsi: Make use of new the sg_map helper function

2017-04-13 Thread Logan Gunthorpe
Convert the kmap and kmap_atomic uses to the sg_map function. We now
store the flags for the kmap instead of a boolean to indicate
atomicitiy. We also propogate a possible kmap error down and create
a new ISCSI_TCP_INTERNAL_ERR error type for this.

Signed-off-by: Logan Gunthorpe 
---
 drivers/scsi/cxgbi/libcxgbi.c |  5 +
 drivers/scsi/libiscsi_tcp.c   | 32 
 include/scsi/libiscsi_tcp.h   |  3 ++-
 3 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
index bd7d39e..e38d0c1 100644
--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c
@@ -1556,6 +1556,11 @@ static inline int read_pdu_skb(struct iscsi_conn *conn,
 */
iscsi_conn_printk(KERN_ERR, conn, "Invalid pdu or skb.");
return -EFAULT;
+   case ISCSI_TCP_INTERNAL_ERR:
+   pr_info("skb 0x%p, off %u, %d, TCP_INTERNAL_ERR.\n",
+   skb, offset, offloaded);
+   iscsi_conn_printk(KERN_ERR, conn, "Internal error.");
+   return -EFAULT;
case ISCSI_TCP_SEGMENT_DONE:
log_debug(1 << CXGBI_DBG_PDU_RX,
"skb 0x%p, off %u, %d, TCP_SEG_DONE, rc %d.\n",
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index 63a1d69..a2427699 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -133,25 +133,23 @@ static void iscsi_tcp_segment_map(struct iscsi_segment 
*segment, int recv)
if (page_count(sg_page(sg)) >= 1 && !recv)
return;
 
-   if (recv) {
-   segment->atomic_mapped = true;
-   segment->sg_mapped = kmap_atomic(sg_page(sg));
-   } else {
-   segment->atomic_mapped = false;
-   /* the xmit path can sleep with the page mapped so use kmap */
-   segment->sg_mapped = kmap(sg_page(sg));
+   /* the xmit path can sleep with the page mapped so don't use atomic */
+   segment->sg_map_flags = recv ? SG_KMAP_ATOMIC : SG_KMAP;
+   segment->sg_mapped = sg_map(sg, segment->sg_map_flags);
+
+   if (IS_ERR(segment->sg_mapped)) {
+   segment->sg_mapped = NULL;
+   return;
}
 
-   segment->data = segment->sg_mapped + sg->offset + segment->sg_offset;
+   segment->data = segment->sg_mapped + segment->sg_offset;
 }
 
 void iscsi_tcp_segment_unmap(struct iscsi_segment *segment)
 {
if (segment->sg_mapped) {
-   if (segment->atomic_mapped)
-   kunmap_atomic(segment->sg_mapped);
-   else
-   kunmap(sg_page(segment->sg));
+   sg_unmap(segment->sg, segment->sg_mapped,
+ segment->sg_map_flags);
segment->sg_mapped = NULL;
segment->data = NULL;
}
@@ -304,6 +302,9 @@ iscsi_tcp_segment_recv(struct iscsi_tcp_conn *tcp_conn,
break;
}
 
+   if (segment->data)
+   return -EFAULT;
+
copy = min(len - copied, segment->size - segment->copied);
ISCSI_DBG_TCP(tcp_conn->iscsi_conn, "copying %d\n", copy);
memcpy(segment->data + segment->copied, ptr + copied, copy);
@@ -927,6 +928,13 @@ int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct 
sk_buff *skb,
  avail);
rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
BUG_ON(rc == 0);
+   if (rc < 0) {
+   ISCSI_DBG_TCP(conn, "memory fault. Consumed %d\n",
+ consumed);
+   *status = ISCSI_TCP_INTERNAL_ERR;
+   goto skb_done;
+   }
+
consumed += rc;
 
if (segment->total_copied >= segment->total_size) {
diff --git a/include/scsi/libiscsi_tcp.h b/include/scsi/libiscsi_tcp.h
index 30520d5..58c79af 100644
--- a/include/scsi/libiscsi_tcp.h
+++ b/include/scsi/libiscsi_tcp.h
@@ -47,7 +47,7 @@ struct iscsi_segment {
struct scatterlist  *sg;
void*sg_mapped;
unsigned intsg_offset;
-   boolatomic_mapped;
+   int sg_map_flags;
 
iscsi_segment_done_fn_t *done;
 };
@@ -92,6 +92,7 @@ enum {
ISCSI_TCP_SKB_DONE, /* skb is out of data */
ISCSI_TCP_CONN_ERR, /* iscsi layer has fired a conn err */
ISCSI_TCP_SUSPENDED,/* conn is suspended */
+   ISCSI_TCP_INTERNAL_ERR, /* an internal error occurred */
 };
 
 extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
-- 
2.1.4