[kvm-unit-tests PULL 13/17] s390x: Add linemode buffer to fix newline on every print

Thomas Huth
2019-09-25T16:38:29Z

Linemode seems to add a newline for each sent message which makes
reading rather hard. Hence we add a small buffer and only print if
it's full or a newline is encountered.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190920112345.2359-1-frankja@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
lib/s390x/sclp-console.c | 43 ++++++++++++++++++++++++++++++++++++----
1 file changed, 39 insertions(+), 4 deletions(-)

diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
index 19416b5..6067a1a 100644
--- a/lib/s390x/sclp-console.c
+++ b/lib/s390x/sclp-console.c
@@ -13,6 +13,7 @@
#include <asm/page.h>
#include <asm/arch_def.h>
#include <asm/io.h>
+#include <asm/spinlock.h>
#include "sclp.h"

/*
@@ -87,6 +88,10 @@ static uint8_t _ascebc[256] = {
0x90, 0x3F, 0x3F, 0x3F, 0x3F, 0xEA, 0x3F, 0xFF
};

+static char lm_buff[120];
+static unsigned char lm_buff_off;
+static struct spinlock lm_buff_lock;
+
static void sclp_print_ascii(const char *str)
{
int len = strlen(str);
@@ -103,10 +108,10 @@ static void sclp_print_ascii(const char *str)
sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
}

-static void sclp_print_lm(const char *str)
+static void lm_print(const char *buff, int len)
{
unsigned char *ptr, *end, ch;
- unsigned int count, offset, len;
+ unsigned int count, offset;
struct WriteEventData *sccb;
struct mdb *mdb;
struct mto *mto;
@@ -117,11 +122,10 @@ static void sclp_print_lm(const char *str)
end = (unsigned char *) sccb + 4096 - 1;
memset(sccb, 0, sizeof(*sccb));
ptr = (unsigned char *) &sccb->msg.mdb.mto;
- len = strlen(str);
offset = 0;
do {
for (count = sizeof(*mto); offset < len; count++) {
- ch = str[offset++];
+ ch = buff[offset++];
if (ch == 0x0a || ptr + count > end)
break;
ptr[count] = _ascebc[ch];
@@ -148,6 +152,37 @@ static void sclp_print_lm(const char *str)
sclp_service_call(SCLP_CMD_WRITE_EVENT_DATA, sccb);
}

+
+/*
+ * In contrast to the ascii console, linemode produces a new
+ * line with every write of data. The report() function uses
+ * several printf() calls to generate a line of data which
+ * would all end up on different lines.
+ *
+ * Hence we buffer here until we encounter a \n or the buffer
+ * is full. That means that linemode output can look a bit
+ * different from ascii and that it takes a bit longer for
+ * lines to appear.
+ */
+static void sclp_print_lm(const char *str)
+{
+ int i;
+ const int len = strlen(str);
+
+ spin_lock(&lm_buff_lock);
+
+ for (i = 0; i < len; i++) {
+ lm_buff[lm_buff_off++] = str[i];
+
+ /* Buffer full or newline? */
+ if (str[i] == '\n' || lm_buff_off == (ARRAY_SIZE(lm_buff) - 1)) {
+ lm_print(lm_buff, lm_buff_off);
+ lm_buff_off = 0;
+ }
+ }
+ spin_unlock(&lm_buff_lock);
+}
+
/*
* SCLP needs to be initialized by setting a send and receive mask,
* indicating which messages the control program (we) want(s) to
--
2.18.1