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virtio: add space for device features show

RFC PATCH In review weiping zhang 2 participants 2 messages Dec 26, 2017 – Jan 8, 2018 virtio core

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weiping zhang

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#0 lore raw

RFC PATCH 1/1 virtio: add space for device features show

make features string more readable, add space every 8bit. example:
00101010 01110000 00000000 00001100

Signed-off-by weiping zhang <[email protected]>
---
 drivers/virtio/virtio.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
drivers/virtio/virtio.c +5 -2
index 59e36ef..d7d2db1 100644
@@ -50,9 +50,12 @@ static ssize_t features_show(struct device *_d,
 
 	/* We actually represent this as a bitstring, as it could be
 	 * arbitrary length in future. */
-	for (i = 0; i < sizeof(dev->features)*8; i++)
-		len += sprintf(buf+len, "%c",
+	for (i = 0; i < sizeof(dev->features) * 8; i++) {
+		len += sprintf(buf + len, "%c",
 			       __virtio_test_bit(dev, i) ? '1' : '0');
+		if (i % 8 == 7)
+			len += sprintf(buf + len, " ");
+	}
 	len += sprintf(buf+len, "\n");
 	return len;
 }
Signature · 1 line
2.9.4
#1 lore raw
Quoted 18 lines · On Tue, 26 Dec 2017 21:35:44 +0800 weiping zhang…

make features string more readable, add space every 8bit. example:
00101010 01110000 00000000 00001100

Signed-off-by weiping zhang <[email protected]>
---
 drivers/virtio/virtio.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
drivers/virtio/virtio.c +0 -1
index 59e36ef..d7d2db1 100644
@@ -50,9 +50,12 @@ static ssize_t features_show(struct device *_d,
 
 	/* We actually represent this as a bitstring, as it could be
 	 * arbitrary length in future. */
-	for (i = 0; i < sizeof(dev->features)*8; i++)

drivers/virtio/virtio.c static ssize_t features_show(struct device *_d, · line 61

Quoted 10 lines
drivers/virtio/virtio.c +5 -1
-		len += sprintf(buf+len, "%c",
+	for (i = 0; i < sizeof(dev->features) * 8; i++) {
+		len += sprintf(buf + len, "%c",
 			       __virtio_test_bit(dev, i) ? '1' : '0');
+		if (i % 8 == 7)
+			len += sprintf(buf + len, " ");
+	}
 	len += sprintf(buf+len, "\n");
 	return len;
 }

This might break consumers of this attribute.

I think the better approach is to write a userspace tool that can do additional helpful stuff (like decoding the feature bits).