Hi Stephan,
I get an issue with md5sum of a big file with kernel 4.9. It don't get
that issue with kernel 4.13.
When I do an strace, I see a difference in the calls: at the end of the
file, with 4.9 md5sum uses sendmsg() for the last block while with 4.13
it uses splice() as for all the previous blocks.
The problem is that the last block has a size over 32kbytes, which is
the maximum size the talitos driver accepts to hash at once.
It looks like sendmsg() sends the entire block to the crypto driver
while splice() calls the crypto driver with blocks of page size.
Is there a way to workaround this issue on 4.9 ? Is there a way to avoid
talitos ahash being called with more than 32kbytes of data ?
strace with 4.9 kernel:
...
vmsplice(5,
[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
558080}], 1, SPLICE_F_MORE|SPLICE_F_GIFT) = 262144
splice(4, NULL, 7, NULL, 262144, SPLICE_F_MORE) = 262144
vmsplice(5,
[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
295936}], 1, SPLICE_F_MORE|SPLICE_F_GIFT) = 262144
splice(4, NULL, 7, NULL, 262144, SPLICE_F_MORE) = 262144
sendmsg(7, {msg_name(0)=NULL,
msg_iov(1)=[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
33792}], msg_controllen=0, msg_flags=0}, MSG_MORE) = -1 EINVAL (Invalid
argument)
write(2, "Generation of hash for file test"..., 45) = 45
...
strace with 4.13 kernel:
...
vmsplice(5,
[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
558080}], 1, SPLICE_F_MORE|SPLICE_F_GIFT) = 262144
splice(4, NULL, 7, NULL, 262144, SPLICE_F_MORE) = 262144
vmsplice(5,
[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
295936}], 1, SPLICE_F_MORE|SPLICE_F_GIFT) = 262144
splice(4, NULL, 7, NULL, 262144, SPLICE_F_MORE) = 262144
vmsplice(5,
[{"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
33792}], 1, SPLICE_F_MORE|SPLICE_F_GIFT) = 33792
splice(4, NULL, 7, NULL, 33792, SPLICE_F_MORE) = 33792
recvmsg(7, {msg_name(0)=NULL,
msg_iov(1)=[{"\"\35|\3273\302\35\252\4\276l\210\315B\210^", 64}],
msg_controllen=0, msg_flags=0}, 0) = 16
fstat64(1, {st_mode=S_IFCHR|0600, st_rdev=makedev(204, 46), ...}) = 0
ioctl(1, TCGETS, {B115200 opost isig icanon echo ...}) = 0
write(1, "221d7cd733c21daa04be6c88cd42885e"..., 39) = 39
...
Thanks
Christophe
