afs: Trace the sending of pages

Add a pair of tracepoints to log the sending of pages for an FS.StoreData
or FS.StoreData64 operation.

Tracepoint afs_send_pages notes each set of pages added to the operation.
There may be several of these per operation as we get up at most 8
contiguous pages in one go because the bvec we're using is on the stack.

Tracepoint afs_sent_pages notes the end of adding data from a whole run of
pages to the operation and the completion of the request phase.
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/rxrpc.c

@@ -308,7 +308,6 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
 
 	do {
 		afs_load_bvec(call, msg, bv, first, last, offset);
-		offset = 0;
 		bytes = msg->msg_iter.count;
 		nr = msg->msg_iter.nr_segs;
 
@@ -318,6 +317,9 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
 		 */
 		if (first + nr - 1 >= last)
 			call->state = AFS_CALL_AWAIT_REPLY;
+		trace_afs_send_pages(call, msg, first, last, offset);
+		offset = 0;
+
 		ret = rxrpc_kernel_send_data(afs_socket, call->rxcall,
 					     msg, bytes);
 		for (loop = 0; loop < nr; loop++)
@@ -328,6 +330,7 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
 		first += nr;
 	} while (first <= last);
 
+	trace_afs_sent_pages(call, first, last, ret);
 	return ret;
 }
 

include/trace/events/afs.h

@@ -310,6 +310,64 @@ TRACE_EVENT(afs_call_done,
 		      __entry->rx_call)
 	    );
 
+TRACE_EVENT(afs_send_pages,
+	    TP_PROTO(struct afs_call *call, struct msghdr *msg,
+		     pgoff_t first, pgoff_t last, unsigned int offset),
+
+	    TP_ARGS(call, msg, first, last, offset),
+
+	    TP_STRUCT__entry(
+		    __field(struct afs_call *,		call		)
+		    __field(pgoff_t,			first		)
+		    __field(pgoff_t,			last		)
+		    __field(unsigned int,		nr		)
+		    __field(unsigned int,		bytes		)
+		    __field(unsigned int,		offset		)
+		    __field(unsigned int,		flags		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->call = call;
+		    __entry->first = first;
+		    __entry->last = last;
+		    __entry->nr = msg->msg_iter.nr_segs;
+		    __entry->bytes = msg->msg_iter.count;
+		    __entry->offset = offset;
+		    __entry->flags = msg->msg_flags;
+			   ),
+
+	    TP_printk(" c=%p %lx-%lx-%lx b=%x o=%x f=%x",
+		      __entry->call,
+		      __entry->first, __entry->first + __entry->nr - 1, __entry->last,
+		      __entry->bytes, __entry->offset,
+		      __entry->flags)
+	    );
+
+TRACE_EVENT(afs_sent_pages,
+	    TP_PROTO(struct afs_call *call, pgoff_t first, pgoff_t last, int ret),
+
+	    TP_ARGS(call, first, last, ret),
+
+	    TP_STRUCT__entry(
+		    __field(struct afs_call *,		call		)
+		    __field(pgoff_t,			first		)
+		    __field(pgoff_t,			last		)
+		    __field(int,			ret		)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->call = call;
+		    __entry->first = first;
+		    __entry->last = last;
+		    __entry->ret = ret;
+			   ),
+
+	    TP_printk(" c=%p %lx-%lx r=%d",
+		      __entry->call,
+		      __entry->first, __entry->last,
+		      __entry->ret)
+	    );
+
 #endif /* _TRACE_AFS_H */
 
 /* This part must be outside protection */