When data digest is enabled for a nvme tcp qpair, we can use accel_fw
to calculate the data crc32c. Then if there are multiple
c2h pdus are coming, we can use both CPU resource directly
and accel_fw framework to caculate the checksum. Then the datao value compare
will not match since we will not update "datao" in the pdu coming order.
For example, if we receive 4 pdus, named as A, B, C, D.
offset data_len (in bytes)
A: 0 8192
B: 8192 4096
C: 12288 8192
D: 20480 4096
For receving the pdu, we hope that we can continue exeution even if
we use the offloading engine in accel_fw. Then in this situation,
if Pdu(C) is offloaded by accel_fw. Then our logic will continue receving
PDU(D). And according to the logic in our code, this time we leverage CPU
to calculate crc32c (Because we only have one active pdu to receive data).
Then we find the expected data offset is still 12288. Because "datao" in tcp_req will
only be updated after calling nvme_tcp_c2h_data_payload_handle function. So
while we enter nvme_tcp_c2h_data_hdr_handle function, we will find the
expected datao value is not as expected compared with the data offset value
contained in Pdu(D).
So the solution is that we create a new variable "expected_datao"
in tcp_req to do the comparation because we want to comply with the tp8000 spec
and do the offset check.
We still need use "datao" to count whether we receive the whole data or not.
So we cannot reuse "datao" variable in an early way. Otherwise, we will
release tcp_req structure early and cause another bug.
PS: This bug was not found early because previously the sw path in accel_fw
directly calculated the crc32c and called the user callback. Now we use a list and the
poller to handle, then it triggers this issue. Definitely, it will be much easier to
trigger this issue if we use real hardware engine.
Fixes#2098
Signed-off-by: Ziye Yang <ziye.yang@intel.com>
Change-Id: I10f5938a6342028d08d90820b2c14e4260134d77
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9612
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: GangCao <gang.cao@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
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