On 12/17/2010 08:38 PM, Jeff Layton wrote: > In order to incorporate async requests, we need to allow for a more > general way to do things on receive, rather than just waking up a > process. > > Turn the task pointer in the mid_q_entry into a callback function and a > generic data pointer. When a response comes in, or the socket is > reconnected, cifsd can call the callback function in order to wake up > the process. > > The default is to just wake up the current process which should mean no > change in behavior for existing code. > > Also, clean up the locking in cifs_reconnect. There doesn't seem to be > any need to hold both the srv_mutex and GlobalMid_Lock when walking the > list of mids. > > Signed-off-by: Jeff Layton <[email protected]> > --- > fs/cifs/cifs_debug.c | 8 +++--- > fs/cifs/cifsglob.h | 15 ++++++++++++- > fs/cifs/connect.c | 56 > +++++++++++++++++++++++++------------------------- > fs/cifs/transport.c | 19 +++++++++++++++- > 4 files changed, 63 insertions(+), 35 deletions(-) > > diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c > index ac7a38f..30d01bc 100644 > --- a/fs/cifs/cifs_debug.c > +++ b/fs/cifs/cifs_debug.c > @@ -79,11 +79,11 @@ void cifs_dump_mids(struct TCP_Server_Info *server) > spin_lock(&GlobalMid_Lock); > list_for_each(tmp, &server->pending_mid_q) { > mid_entry = list_entry(tmp, struct mid_q_entry, qhead); > - cERROR(1, "State: %d Cmd: %d Pid: %d Tsk: %p Mid %d", > + cERROR(1, "State: %d Cmd: %d Pid: %d Cbdata: %p Mid %d", > mid_entry->midState, > (int)mid_entry->command, > mid_entry->pid, > - mid_entry->tsk, > + mid_entry->callback_data, > mid_entry->mid); > #ifdef CONFIG_CIFS_STATS2 > cERROR(1, "IsLarge: %d buf: %p time rcv: %ld now: %ld", > @@ -218,11 +218,11 @@ static int cifs_debug_data_proc_show(struct seq_file > *m, void *v) > mid_entry = list_entry(tmp3, struct mid_q_entry, > qhead); > seq_printf(m, "\tState: %d com: %d pid:" > - " %d tsk: %p mid %d\n", > + " %d cbdata: %p mid %d\n", > mid_entry->midState, > (int)mid_entry->command, > mid_entry->pid, > - mid_entry->tsk, > + mid_entry->callback_data, > mid_entry->mid); > } > spin_unlock(&GlobalMid_Lock); > diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h > index 8c3c165..db90fe0 100644 > --- a/fs/cifs/cifsglob.h > +++ b/fs/cifs/cifsglob.h > @@ -508,6 +508,18 @@ static inline void cifs_stats_bytes_read(struct > cifsTconInfo *tcon, > > #endif > > +struct mid_q_entry; > + > +/* > + * This is the prototype for the mid callback function. When creating one, > + * take special care to avoid deadlocks. Things to bear in mind: > + * > + * - it will be called by cifsd > + * - the GlobalMid_Lock will be held > + * - the mid will be removed from the pending_mid_q list > + */ > +typedef void (mid_callback_t)(struct mid_q_entry *mid); > + > /* one of these for every pending CIFS request to the server */ > struct mid_q_entry { > struct list_head qhead; /* mids waiting on reply from this server */ > @@ -519,7 +531,8 @@ struct mid_q_entry { > unsigned long when_sent; /* time when smb send finished */ > unsigned long when_received; /* when demux complete (taken off wire) */ > #endif > - struct task_struct *tsk; /* task waiting for response */ > + mid_callback_t *callback; /* call completion callback */ > + void *callback_data; /* general purpose pointer for callback */ > struct smb_hdr *resp_buf; /* response buffer */ > int midState; /* wish this were enum but can not pass to wait_event */ > __u8 command; /* smb command code */ > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > index 515cafa..734fb09 100644 > --- a/fs/cifs/connect.c > +++ b/fs/cifs/connect.c > @@ -152,6 +152,7 @@ cifs_reconnect(struct TCP_Server_Info *server) > > /* before reconnecting the tcp session, mark the smb session (uid) > and the tid bad so they are not used until reconnected */ > + cFYI(1, "%s: marking sessions and tcons for reconnect", __func__); > spin_lock(&cifs_tcp_ses_lock); > list_for_each(tmp, &server->smb_ses_list) { > ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list); > @@ -163,7 +164,9 @@ cifs_reconnect(struct TCP_Server_Info *server) > } > } > spin_unlock(&cifs_tcp_ses_lock); > + > /* do not want to be sending data on a socket we are freeing */ > + cFYI(1, "%s: tearing down socket", __func__); > mutex_lock(&server->srv_mutex); > if (server->ssocket) { > cFYI(1, "State: 0x%x Flags: 0x%lx", server->ssocket->state, > @@ -180,22 +183,22 @@ cifs_reconnect(struct TCP_Server_Info *server) > kfree(server->session_key.response); > server->session_key.response = NULL; > server->session_key.len = 0; > + mutex_unlock(&server->srv_mutex); > > + /* > + * move in-progress mids to a private list so that we can walk it later > + * without needing a lock. We'll mark them for retry after reconnect. > + */ > + cFYI(1, "%s: issuing mid callbacks", __func__);
Is the above comment valid? This patchset doesn't use a separate list IIUC? -- Suresh Jayaraman -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
