Add user friendly command strings sd_wce_rcd to enable/disable
write&read cache. User can enable both write and read cache by one of
the following commands:
echo 10 > cache_type
echo "write back" > cache_type
wce rcd write_cache read_cache
0 0 off on
0 1 off off
1 0 on on
1 1 on off
When execute "cat cache_type", it will show more detail info like following:
write back
10
write:on, read:on
Signed-off-by: weiping zhang <zhangweiping@xxxxxxxxxxxxxxx>
---
drivers/scsi/sd.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a028ab3..722e440 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -139,6 +139,15 @@ static const char *sd_cache_types[] = {
"write back, no read (daft)"
};
+/*
+ * wce rcd write_cache read_cache
+ * 0 0 off on
+ * 0 1 off off
+ * 1 0 on on
+ * 1 1 on off
+ */
+static const char * const sd_wce_rcd[] = {"00", "01", "10", "11"};
+
static void sd_set_flush_flag(struct scsi_disk *sdkp)
{
bool wc = false, fua = false;
@@ -180,8 +189,11 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
}
ct = sysfs_match_string(sd_cache_types, buf);
- if (ct < 0)
- return -EINVAL;
+ if (ct < 0) {
+ ct = sysfs_match_string(sd_wce_rcd, buf);
+ if (ct < 0)
+ return -EINVAL;
+ }
rcd = ct & 0x01 ? 1 : 0;
wce = (ct & 0x02) && !sdkp->write_prot ? 1 : 0;
@@ -282,7 +294,9 @@ cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
struct scsi_disk *sdkp = to_scsi_disk(dev);
int ct = sdkp->RCD + 2*sdkp->WCE;
- return sprintf(buf, "%s\n", sd_cache_types[ct]);
+ return sprintf(buf, "%s\n%s\nwrite:%s, read:%s\n", sd_cache_types[ct],
+ sd_wce_rcd[ct], sdkp->WCE ? "on" : "off",
+ sdkp->RCD ? "off" : "on");
}
static DEVICE_ATTR_RW(cache_type);
--
2.9.4
