[PATCH 05/13] drm: Add put callback for the coredump printer

[Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>]

Add a put function for the coredump printer to bypass printf()
for constant strings for a speed boost.

Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
---
 drivers/gpu/drm/drm_print.c | 42 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_print.h     |  2 ++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index bef8f0ec5d73..bec912215b35 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -30,6 +30,48 @@
 #include <drm/drmP.h>
 #include <drm/drm_print.h>
 
+void __drm_puts_coredump(struct drm_printer *p, const char *str)
+{
+	struct drm_print_iterator *iterator = p->arg;
+
+	ssize_t len;
+
+	if (!iterator->remain)
+		return;
+
+	if (iterator->offset < iterator->start) {
+		ssize_t copy;
+
+		len = strlen(str);
+
+		if (iterator->offset + len <= iterator->start) {
+			iterator->offset += len;
+			return;
+		}
+
+		copy = len - (iterator->start - iterator->offset);
+
+		if (copy > iterator->remain)
+			copy = iterator->remain;
+
+		/* Copy out the bit of the string that we need */
+		memcpy(iterator->data,
+			str + (iterator->start - iterator->offset), copy);
+
+		iterator->offset = iterator->start + copy;
+		iterator->remain -= copy;
+	} else {
+		ssize_t pos = iterator->offset - iterator->start;
+
+		len = min_t(ssize_t, strlen(str), iterator->remain);
+
+		memcpy(iterator->data + pos, str, len);
+
+		iterator->offset += len;
+		iterator->remain -= len;
+	}
+}
+
 void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf)
 {
 	struct drm_print_iterator *iterator = p->arg;
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 3bc6ba4b7b2c..2a903ee7b428 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -75,6 +75,7 @@ struct drm_printer {
 };
 
 void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf);
+void __drm_puts_coredump(struct drm_printer *p, const char *str);
 void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf);
 void __drm_puts_seq_file(struct drm_printer *p, const char *str);
 void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf);
@@ -129,6 +130,7 @@ drm_coredump_printer(struct drm_print_iterator *iter)
 {
 	struct drm_printer p = {
 		.printfn = __drm_printfn_coredump,
+		.puts = __drm_puts_coredump,
 		.arg = iter,
 	};
 	return p;
-- 
2.17.1

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