[Crash-utility] Re: Adding the zram decompression algorithm "lzo-rle" to support kernel versions >= 5.1

["Tang Yulong" <1637403063@xxxxxx>]

OK, I have made the modifications as per your suggestions. Should I proceed with resubmitting the patch? And how should I acknowledge your contribution? I'm not quite clear on that for the first submission. Thank you for your guidance.

Thanks,
Yulong

diff --git a/lzorle_decompress.c b/lzorle_decompress.c
index bd7ee3f..5e83430 100644
--- a/lzorle_decompress.c
+++ b/lzorle_decompress.c
@@ -20,6 +20,8 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "defs.h"
+
 /* This MAX_255_COUNT is the maximum number of times we can add 255 to a base
  * count without overflowing an integer. The multiply will overflow when
  * multiplying 255 by more than MAXINT/255. The sum will overflow earlier
@@ -91,7 +93,28 @@ int lzorle_decompress_safe(const unsigned char *in, unsigned long in_len,
 				}
 				t += 3;
 copy_literal_run:
-				{
+				if (get_kernel_config("CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS", NULL) == IKCONFIG_Y) {
+					if (HAVE_IP(t + 15) && HAVE_OP(t + 15)) {
+						const unsigned char *ie = ip + t;
+						unsigned char *oe = op + t;
+						do {
+							COPY8(op, ip);
+							op += 8;
+							ip += 8;
+							COPY8(op, ip);
+							op += 8;
+							ip += 8;
+						} while (ip < ie);
+						ip = ie;
+						op = oe;
+					} else {
+						NEED_OP(t);
+						NEED_IP(t + 3);
+						do {
+							*op++ = *ip++;
+						} while (--t > 0);
+					}
+				} else {
 					NEED_OP(t);
 					NEED_IP(t + 3);
 					do {
@@ -194,7 +217,45 @@ copy_literal_run:
 			}
 		}
 		TEST_LB(m_pos);
-		{
+
+		if (get_kernel_config("CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS", NULL) == IKCONFIG_Y) {
+			if (op - m_pos >= 8) {
+				unsigned char *oe = op + t;
+				if (HAVE_OP(t + 15)) {
+					do {
+						COPY8(op, m_pos);
+						op += 8;
+						m_pos += 8;
+						COPY8(op, m_pos);
+						op += 8;
+						m_pos += 8;
+					} while (op < oe);
+					op = oe;
+					if (HAVE_IP(6)) {
+						state = next;
+						COPY4(op, ip);
+						op += next;
+						ip += next;
+						continue;
+					}
+				} else {
+					NEED_OP(t);
+					do {
+						*op++ = *m_pos++;
+					} while (op < oe);
+				}
+			} else {
+				unsigned char *oe = op + t;
+				NEED_OP(t);
+				op[0] = m_pos[0];
+				op[1] = m_pos[1];
+				op += 2;
+				m_pos += 2;
+				do {
+					*op++ = *m_pos++;
+				} while (op < oe);
+			}
+		} else {
 			unsigned char *oe = op + t;
 			NEED_OP(t);
 			op[0] = m_pos[0];
@@ -208,7 +269,20 @@ copy_literal_run:
 match_next:
 		state = next;
 		t = next;
-		{
+		if (get_kernel_config("CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS", NULL) == IKCONFIG_Y) {
+			if (HAVE_IP(6) && HAVE_OP(4)) {
+				COPY4(op, ip);
+				op += t;
+				ip += t;
+			} else {
+				NEED_IP(t + 3);
+				NEED_OP(t);
+				while (t > 0) {
+					*op++ = *ip++;
+					t--;
+				}
+			}
+		} else {
 			NEED_IP(t + 3);
 			NEED_OP(t);
 			while (t > 0) {
--
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