This has the nice side effect to remove the compiler warning
"dereferencing type-punned pointer will break strict-aliasing rules"
which occur since gcc-4.7.
There are 79 locations where the warning occurs. All of them are in
statements where the htonl/htons/ntohl/ntohs functions are used, e.g.:
in lib/pdu.c itt = ntohl(*(uint32_t *)&in->hdr[16]);
in lib/scsi-lowlevel.c *(uint32_t *)&task->cdb[2] = htonl(lba);
The warning is not related to the htonl/htons/ntohl/ntohs functions but
to the casting/dereferencing operation. If the dereferenced variable is
already a pointer, the warning does not not occur, e.g. this one:
in lib/pdu.c itt = ntohl(*(uint32_t *)&in->data[16]);
The warning is caused by the -fstrict-aliasing option. The
-fstrict-aliasing option is enabled at optimization levels -O2, -O3, -Os.
Signed-off-by: Bernhard Kohl <bernhard.kohl@gmx.net>
These two functions belong in the iscsi layer, not the scsi layer so move them
out from scsi-lowlevel.c so that we can start turning scsi-lowlevel.c to a pure
scsi layer and remove all dependencies to iscsi from it.
It is not real zero-copy since the data is still copied in the kernel,
but it avoids copying the data inside libiscsi as well as in the callback.
For SCSI tasks that will return data from the target, the application can now
specify application buffers for libiscsi to read the data directly into.
This is done by calling scsi_task_add_data_in_buffer(task, ...
These buffers need not be linear, you can specify different areas to read into
by calling this function several times.
See examples/iscsiclient.c for an example.
