[PATCH v4 2/3] drm/printer: Allow NULL data in devcoredump printer

[Matthew Brost]

Useful to determine size of devcoreump before writing it out.

Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/drm_print.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index cf24dfdeb6b2..a1a4de9f9c44 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -100,8 +100,9 @@ void __drm_puts_coredump(struct drm_printer *p, const char *str)
 			copy = iterator->remain;
 
 		/* Copy out the bit of the string that we need */
-		memcpy(iterator->data,
-			str + (iterator->start - iterator->offset), copy);
+		if (iterator->data)
+			memcpy(iterator->data,
+				str + (iterator->start - iterator->offset), copy);
 
 		iterator->offset = iterator->start + copy;
 		iterator->remain -= copy;
@@ -110,7 +111,8 @@ void __drm_puts_coredump(struct drm_printer *p, const char *str)
 
 		len = min_t(ssize_t, strlen(str), iterator->remain);
 
-		memcpy(iterator->data + pos, str, len);
+		if (iterator->data)
+			memcpy(iterator->data + pos, str, len);
 
 		iterator->offset += len;
 		iterator->remain -= len;
@@ -140,8 +142,9 @@ void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf)
 	if ((iterator->offset >= iterator->start) && (len < iterator->remain)) {
 		ssize_t pos = iterator->offset - iterator->start;
 
-		snprintf(((char *) iterator->data) + pos,
-			iterator->remain, "%pV", vaf);
+		if (iterator->data)
+			snprintf(((char *) iterator->data) + pos,
+				iterator->remain, "%pV", vaf);
 
 		iterator->offset += len;
 		iterator->remain -= len;
-- 
2.34.1