2011/4/8 Steve French <[email protected]>:
> Update on cifs vs. smb2 mids, and the smb2 sendrcv2. Jeff had
> suggested more closely matching the cifs and smb2 mids, in particular
> extending the 16 bit cifs mid (multiplex identifier for inflight
> network requests) to the 64 bit size needed for smb2 (and thus masking
> the mid when used for cifs) and having cifs ignore the various smb2
> unique fields in the mid (which makes the mid larger for cifs).
> Since the smb2 code in cifs-2.6.git (put in February and early March)
> has now been rereviewed, the next step in the smb2 merge is posting
> and reviewing the transport routine for smb2 (smb2_sendrcv2 or reusing
> cifs_sendrcv2) - the latter may make more sense if we go to a common
> mid for cifs and smb2. At the fs summit, Jeff and Jeremy and I
> talked about this, but Pavel and others may have opinions on this
> topic. As soon as the cifs merge activity settles down for 2.6.39, I
> plan to post sendrcv2 alternatives and then begin work with Pavel on
> the superblock, file and inode routines and seeing whether for smb2
> they should be smb2 unique (as we originally expected since smb2 is
> handle based, and simpler) and look more like they did in the smb2.ko
> work that Pavel did last summer or should be more common with the cifs
> routines.
>
> --
> Thanks,
>
> Steve
> --
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>
I suggest to make cifs and smb2 protocol mid structures use common
structure that has equals fields for both and then expand this
structure for protocol-dependent things.
It can look like this:
/* one of these for every pending CIFS request to the server */
struct mid_q_entry {
__u8 protocol_id;
struct list_head qhead; /* mids waiting on reply from this server */
int midState; /* wish this were enum but can not pass to wait_event */
unsigned long when_alloc; /* when mid was created */
#ifdef CONFIG_CIFS_STATS2
unsigned long when_sent; /* time when smb send finished */
unsigned long when_received; /* when demux complete (taken off wire) */
#endif
bool largeBuf:1; /* if valid response, is pointer to large buf */
void *resp_buf; /* response buffer */
mid_callback_t *callback; /* call completion callback */
void *callback_data; /* general purpose pointer for callback */
};
struct cifs_mid_q_entry {
struct mid_q_entry mid_q;
__u16 mid; /* multiplex id */
__u32 sequence_number; /* for CIFS signing */
__u8 command; /* smb command code */
__u16 pid; /* process id */
bool multiRsp:1; /* multiple trans2 responses for one request */
bool multiEnd:1; /* both received */
};
struct smb2_mid_q_entry {
struct mid_q_entry mid_q;
__u64 mid; /* multiplex id(s), bigger for smb2 */
__le16 command; /* smb2 command code */
__u32 pid; /* process id - bigger for smb2 than cifs */
};
So, we always work with a pointer to common structure mid_q_entry and
then expand it according to protocol_id filed when we need it:
#define PROTOCOL_ID(mid) (*((__u8 *)mid))
process_mid(struct mid_q_entry *pmid)
{
if (PROTOCOL_ID(pmid) == SMB2)
process_smb2_mid((struct smb2_mid_q_entry *)pmid);
else
process_cifs_mid((struct cifs_mid_q_entry *)pmid);
}
--
Best regards,
Pavel Shilovsky.
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