newbus: Move from bus_child_{pnpinfo,location}_src to bus_child_{pnpinfo,location} with sbuf

Now that the upper layers all go through a layer to tie into these
information functions that translates an sbuf into char * and len. The
current interface suffers issues of what to do in cases of truncation,
etc. Instead, migrate all these functions to using struct sbuf and these
issues go away. The caller is also in charge of any memory allocation
and/or expansion that's needed during this process.

Create a bus_generic_child_{pnpinfo,location} and make it default. It
just returns success. This is for those busses that have no information
for these items. Migrate the now-empty routines to using this as
appropriate.

Document these new interfaces with man pages, and oversight from before.

Reviewed by:		jhb, bcr
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D29937

3 files changed, 18 insertions, 23 deletions

diff --git a/sys/dev/sound/pci/hda/hdaa.c b/sys/dev/sound/pci/hda/hdaa.c
index 8eeeadce6666..ae7d77d431b2 100644
--- a/sys/dev/sound/pci/hda/hdaa.c
+++ b/sys/dev/sound/pci/hda/hdaa.c
@@ -6738,23 +6738,21 @@ hdaa_print_child(device_t dev, device_t child)
 }
 
 static int
-hdaa_child_location_str(device_t dev, device_t child, char *buf,
-    size_t buflen)
+hdaa_child_location(device_t dev, device_t child, struct sbuf *sb)
 {
 	struct hdaa_devinfo *devinfo = device_get_softc(dev);
 	struct hdaa_pcm_devinfo *pdevinfo =
 	    (struct hdaa_pcm_devinfo *)device_get_ivars(child);
 	struct hdaa_audio_as *as;
-	int first = 1, i, len = 0;
+	int first = 1, i;
 
-	len += snprintf(buf + len, buflen - len, "nid=");
+	sbuf_printf(sb, "nid=");
 	if (pdevinfo->playas >= 0) {
 		as = &devinfo->as[pdevinfo->playas];
 		for (i = 0; i < 16; i++) {
 			if (as->pins[i] <= 0)
 				continue;
-			len += snprintf(buf + len, buflen - len,
-			    "%s%d", first ? "" : ",", as->pins[i]);
+			sbuf_printf(sb, "%s%d", first ? "" : ",", as->pins[i]);
 			first = 0;
 		}
 	}
@@ -6763,8 +6761,7 @@ hdaa_child_location_str(device_t dev, device_t child, char *buf,
 		for (i = 0; i < 16; i++) {
 			if (as->pins[i] <= 0)
 				continue;
-			len += snprintf(buf + len, buflen - len,
-			    "%s%d", first ? "" : ",", as->pins[i]);
+			sbuf_printf(sb, "%s%d", first ? "" : ",", as->pins[i]);
 			first = 0;
 		}
 	}
@@ -6830,7 +6827,7 @@ static device_method_t hdaa_methods[] = {
 	DEVMETHOD(device_resume,	hdaa_resume),
 	/* Bus interface */
 	DEVMETHOD(bus_print_child,	hdaa_print_child),
-	DEVMETHOD(bus_child_location_str, hdaa_child_location_str),
+	DEVMETHOD(bus_child_location,	hdaa_child_location),
 	DEVMETHOD(hdac_stream_intr,	hdaa_stream_intr),
 	DEVMETHOD(hdac_unsol_intr,	hdaa_unsol_intr),
 	DEVMETHOD(hdac_pindump,		hdaa_pindump),
diff --git a/sys/dev/sound/pci/hda/hdac.c b/sys/dev/sound/pci/hda/hdac.c
index ec907715c5b1..b1fb193595fe 100644
--- a/sys/dev/sound/pci/hda/hdac.c
+++ b/sys/dev/sound/pci/hda/hdac.c
@@ -1774,21 +1774,20 @@ hdac_print_child(device_t dev, device_t child)
 }
 
 static int
-hdac_child_location_str(device_t dev, device_t child, char *buf, size_t buflen)
+hdac_child_location(device_t dev, device_t child, struct sbuf *sb)
 {
 
-	snprintf(buf, buflen, "cad=%d", (int)(intptr_t)device_get_ivars(child));
+	sbuf_printf(sb, "cad=%d", (int)(intptr_t)device_get_ivars(child));
 	return (0);
 }
 
 static int
-hdac_child_pnpinfo_str_method(device_t dev, device_t child, char *buf,
-    size_t buflen)
+hdac_child_pnpinfo_method(device_t dev, device_t child, struct sbuf *sb)
 {
 	struct hdac_softc *sc = device_get_softc(dev);
 	nid_t cad = (uintptr_t)device_get_ivars(child);
 
-	snprintf(buf, buflen,
+	sbuf_printf(sb,
 	    "vendor=0x%04x device=0x%04x revision=0x%02x stepping=0x%02x",
 	    sc->codecs[cad].vendor_id, sc->codecs[cad].device_id,
 	    sc->codecs[cad].revision_id, sc->codecs[cad].stepping_id);
@@ -2137,8 +2136,8 @@ static device_method_t hdac_methods[] = {
 	/* Bus interface */
 	DEVMETHOD(bus_get_dma_tag,	hdac_get_dma_tag),
 	DEVMETHOD(bus_print_child,	hdac_print_child),
-	DEVMETHOD(bus_child_location_str, hdac_child_location_str),
-	DEVMETHOD(bus_child_pnpinfo_str, hdac_child_pnpinfo_str_method),
+	DEVMETHOD(bus_child_location,	hdac_child_location),
+	DEVMETHOD(bus_child_pnpinfo,	hdac_child_pnpinfo_method),
 	DEVMETHOD(bus_read_ivar,	hdac_read_ivar),
 	DEVMETHOD(hdac_get_mtx,		hdac_get_mtx),
 	DEVMETHOD(hdac_codec_command,	hdac_codec_command),
diff --git a/sys/dev/sound/pci/hda/hdacc.c b/sys/dev/sound/pci/hda/hdacc.c
index 3b1ca7ea61e5..ff72498ecb9f 100644
--- a/sys/dev/sound/pci/hda/hdacc.c
+++ b/sys/dev/sound/pci/hda/hdacc.c
@@ -542,21 +542,20 @@ hdacc_detach(device_t dev)
 }
 
 static int
-hdacc_child_location_str(device_t dev, device_t child, char *buf, size_t buflen)
+hdacc_child_location(device_t dev, device_t child, struct sbuf *sb)
 {
 	struct hdacc_fg *fg = device_get_ivars(child);
 
-	snprintf(buf, buflen, "nid=%d", fg->nid);
+	sbuf_printf(sb, "nid=%d", fg->nid);
 	return (0);
 }
 
 static int
-hdacc_child_pnpinfo_str_method(device_t dev, device_t child, char *buf,
-    size_t buflen)
+hdacc_child_pnpinfo_method(device_t dev, device_t child, struct sbuf *sb)
 {
 	struct hdacc_fg *fg = device_get_ivars(child);
 
-	snprintf(buf, buflen, "type=0x%02x subsystem=0x%08x",
+	sbuf_printf(sb, "type=0x%02x subsystem=0x%08x",
 	    fg->type, fg->subsystem_id);
 	return (0);
 }
@@ -766,8 +765,8 @@ static device_method_t hdacc_methods[] = {
 	DEVMETHOD(device_suspend,	hdacc_suspend),
 	DEVMETHOD(device_resume,	hdacc_resume),
 	/* Bus interface */
-	DEVMETHOD(bus_child_location_str, hdacc_child_location_str),
-	DEVMETHOD(bus_child_pnpinfo_str, hdacc_child_pnpinfo_str_method),
+	DEVMETHOD(bus_child_location,	hdacc_child_location),
+	DEVMETHOD(bus_child_pnpinfo,	hdacc_child_pnpinfo_method),
 	DEVMETHOD(bus_print_child,	hdacc_print_child),
 	DEVMETHOD(bus_probe_nomatch,	hdacc_probe_nomatch),
 	DEVMETHOD(bus_read_ivar,	hdacc_read_ivar),