Re: SYSFS "errors"

Mauro Carvalho Chehab
2013-02-19T14:35:21Z

Em Tue, 19 Feb 2013 14:50:56 +0100
Borislav Petkov <bp@alien8.de> escreveu:

> On Tue, Feb 19, 2013 at 03:38:09PM +0200, Felipe Balbi wrote:
> > because changing the permission will cause the same issue:
>
> Actually, I take that back. Mauro's patch will already create the file
> anyway:
>
> if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate)
>
> Adjusting the permissions is simply the last missing piece to this patch
> to make the interface to userspace 100% coherent.

That's covers everything but Hannes arguments. I don't think that
adding just one more device_create_file() on a driver that creates
dozens (or hundreds) of sys nodes, depending on the number of DIMMS
on the system would make it any worse.

Regards,
Mauro

[PATCH EDAC] edac: only create sdram_scrub_rate where supported

Currently, sdram_scrub_rate sysfs node is created even if the device
doesn't support get/set the scub rate. Change the logic to only
create this device node when the operation is supported.

Reported-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 9c58da6..4f4b613 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -7,7 +7,7 @@
*
* Written Doug Thompson <norsk5@xmission.com> www.softwarebitmaker.com
*
- * (c) 2012 - Mauro Carvalho Chehab <mchehab@redhat.com>
+ * (c) 2012-2013 - Mauro Carvalho Chehab <mchehab@redhat.com>
* The entire API were re-written, and ported to use struct device
*
*/
@@ -681,9 +681,6 @@ static ssize_t mci_sdram_scrub_rate_store(struct device *dev,
unsigned long bandwidth = 0;
int new_bw = 0;

- if (!mci->set_sdram_scrub_rate)
- return -ENODEV;
-
if (strict_strtoul(data, 10, &bandwidth) < 0)
return -EINVAL;

@@ -707,9 +704,6 @@ static ssize_t mci_sdram_scrub_rate_show(struct device *dev,
struct mem_ctl_info *mci = to_mci(dev);
int bandwidth = 0;

- if (!mci->get_sdram_scrub_rate)
- return -ENODEV;
-
bandwidth = mci->get_sdram_scrub_rate(mci);
if (bandwidth < 0) {
edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n");
@@ -870,8 +864,7 @@ DEVICE_ATTR(ce_count, S_IRUGO, mci_ce_count_show, NULL);
DEVICE_ATTR(max_location, S_IRUGO, mci_max_location_show, NULL);

/* memory scrubber attribute file */
-DEVICE_ATTR(sdram_scrub_rate, S_IRUGO | S_IWUSR, mci_sdram_scrub_rate_show,
- mci_sdram_scrub_rate_store);
+DEVICE_ATTR(sdram_scrub_rate, 0, NULL, NULL);

static struct attribute *mci_attrs[] = {
&dev_attr_reset_counters.attr,
@@ -882,7 +875,6 @@ static struct attribute *mci_attrs[] = {
&dev_attr_ce_noinfo_count.attr,
&dev_attr_ue_count.attr,
&dev_attr_ce_count.attr,
- &dev_attr_sdram_scrub_rate.attr,
&dev_attr_max_location.attr,
NULL
};
@@ -1017,6 +1009,22 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
return err;
}

+ if (mci->set_sdram_scrub_rate || mci->get_sdram_scrub_rate) {
+ if (mci->get_sdram_scrub_rate) {
+ dev_attr_sdram_scrub_rate.attr.mode |= S_IRUGO;
+ dev_attr_sdram_scrub_rate.show = &mci_sdram_scrub_rate_show;
+ }
+ if (mci->set_sdram_scrub_rate) {
+ dev_attr_sdram_scrub_rate.attr.mode |= S_IWUSR;
+ dev_attr_sdram_scrub_rate.store = &mci_sdram_scrub_rate_store;
+ }
+ err = device_create_file(&mci->dev,
+ &dev_attr_sdram_scrub_rate);
+ if (err) {
+ edac_dbg(1, "failure: create sdram_scrub_rate\n");
+ goto fail2;
+ }
+ }
/*
* Create the dimm/rank devices
*/
@@ -1061,6 +1069,7 @@ fail:
continue;
device_unregister(&dimm->dev);
}
+fail2:
device_unregister(&mci->dev);
bus_unregister(&mci->bus);
kfree(mci->bus.name);

--

Cheers,
Mauro