Re: [PATCH 11/11] netlink: add documentation for memory mapped I/O

On Monday 2012-08-20 08:18, Patrick McHardy wrote:

+
+RX and TX rings
+----------------
+
+Each ring contains a number of continous memory blocks, containing frames of
+fixed size dependant on the parameters used for ring setup.

dependent

+The blocks are only visible to the kernel, from the point of view of user-space
+the ring just contains the frames in a continous memory zone.

...to the kernel; from the user-space point of view, the ring...

continuous (multiple occurrences)

+Ring frames
+------------
+
+Each frames contain a frame header, consisting of a synchronization word and some

Each frame contains a frame header,

+The possible values in the status word are:
+
+- NL_MMAP_STATUS_UNUSED:
+	RX ring:	frame belongs to the kernel and contains no message

The frame (mult)

+			for user-space. Approriate action is to invoke poll()
+			to wait for new messages.

The appropriate (mult)

+			if (hdr->nm_status == NL_MMAP_STATUS_VALID)
+				/* Regular memory mapped frame */
+				nlh = (void *hdr) + NL_MMAP_HDRLEN;

(void *)hdr + NL_MMAP_HDRLEN