[char-misc-next 01/27] mei: debugfs: adjust active clients print buffer

From: Tomas Winkler
Date: Sun Feb 07 2016 - 16:44:50 EST


From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

In case of many active host clients clients (41 and more) 1K buffer
is not enough for full information print.
Calculate buffer size according to real clients number.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
drivers/misc/mei/debugfs.c | 29 ++++++++++++++++++++++-------
1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index a138d8a27ab5..9f5410b98688 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/drivers/misc/mei/debugfs.c
@@ -50,6 +50,7 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
}

pos += scnprintf(buf + pos, bufsz - pos, HDR);
+#undef HDR

/* if the driver is not enabled the list won't be consistent */
if (dev->dev_state != MEI_DEV_ENABLED)
@@ -90,23 +91,37 @@ static ssize_t mei_dbgfs_read_active(struct file *fp, char __user *ubuf,
{
struct mei_device *dev = fp->private_data;
struct mei_cl *cl;
- const size_t bufsz = 1024;
+ size_t bufsz = 1;
char *buf;
int i = 0;
int pos = 0;
int ret;

+#define HDR " |me|host|state|rd|wr|\n"
+
if (!dev)
return -ENODEV;

+ mutex_lock(&dev->device_lock);
+
+ /*
+ * if the driver is not enabled the list won't be consistent,
+ * we output empty table
+ */
+ if (dev->dev_state == MEI_DEV_ENABLED)
+ list_for_each_entry(cl, &dev->file_list, link)
+ bufsz++;
+
+ bufsz *= sizeof(HDR) + 1;
+
buf = kzalloc(bufsz, GFP_KERNEL);
- if (!buf)
+ if (!buf) {
+ mutex_unlock(&dev->device_lock);
return -ENOMEM;
+ }

- pos += scnprintf(buf + pos, bufsz - pos,
- " |me|host|state|rd|wr|\n");
-
- mutex_lock(&dev->device_lock);
+ pos += scnprintf(buf + pos, bufsz - pos, HDR);
+#undef HDR

/* if the driver is not enabled the list won't be consistent */
if (dev->dev_state != MEI_DEV_ENABLED)
@@ -115,7 +130,7 @@ static ssize_t mei_dbgfs_read_active(struct file *fp, char __user *ubuf,
list_for_each_entry(cl, &dev->file_list, link) {

pos += scnprintf(buf + pos, bufsz - pos,
- "%2d|%2d|%4d|%5d|%2d|%2d|\n",
+ "%3d|%2d|%4d|%5d|%2d|%2d|\n",
i, mei_cl_me_id(cl), cl->host_client_id, cl->state,
!list_empty(&cl->rd_completed), cl->writing_state);
i++;
--
2.4.3