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Message-Id: <1206208949.4393.25.camel@localhost.localdomain>
Date: Sat, 22 Mar 2008 13:02:28 -0500
From: James Bottomley <James.Bottomley@...senPartnership.com>
To: Greg KH <greg@...ah.com>
Cc: Hannes Reinecke <hare@...e.de>, Kay Sievers <kay.sievers@...y.org>,
linux-scsi <linux-scsi@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] sysfs: allow the group is_visible() method to
return a mode and add an update API
On Fri, 2008-03-21 at 15:26 -0700, Greg KH wrote:
> On Fri, Mar 21, 2008 at 04:27:12PM -0500, James Bottomley wrote:
> > We have a problem in scsi_transport_spi in that we need to customise
> > not only the visibility of the attributes, but also their mode. Fix
> > this by making the is_visible() callback return a mode, with 0
> > indicating is not visible.
> >
> > Also add a sysfs_update_group() API to allow us to change either the
> > visibility or mode of the files at any time on the fly.
> >
> > Signed-off-by: James Bottomley <James.Bottomley@...senPartnership.com>
> > ---
> >
> > Greg, can I take this through SCSI, please ... assuming it's OK? We
> > need this to fix up the SPI transport class.
>
> Sure. But can you document that "update" field a bit more so we can
> remember what it means in the future?
How about this? I also added docbook for create and update attribute
group.
James
---
From: James Bottomley <James.Bottomley@...senPartnership.com>
Date: Thu, 20 Mar 2008 20:47:52 -0500
Subject: [SCSI] sysfs: make group is_valid return a mode_t
We have a problem in scsi_transport_spi in that we need to customise
not only the visibility of the attributes, but also their mode. Fix
this by making the is_visible() callback return a mode, with 0
indicating is not visible.
Also add a sysfs_update_group() API to allow us to change either the
visibility or mode of the files at any time on the fly.
Signed-off-by: James Bottomley <James.Bottomley@...senPartnership.com>
---
fs/sysfs/file.c | 14 ++++++--
fs/sysfs/group.c | 77 +++++++++++++++++++++++++++++++++++++++++-------
fs/sysfs/sysfs.h | 2 +
include/linux/sysfs.h | 4 ++-
4 files changed, 80 insertions(+), 17 deletions(-)
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 6f5954a..8f7ee10 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -490,11 +490,10 @@ const struct file_operations sysfs_file_operations = {
.poll = sysfs_poll,
};
-
-int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
- int type)
+int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
+ const struct attribute *attr, int type, mode_t amode)
{
- umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
+ umode_t mode = (amode & S_IALLUGO) | S_IFREG;
struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
int rc;
@@ -515,6 +514,13 @@ int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
}
+int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
+ int type)
+{
+ return sysfs_add_file_mode(dir_sd, attr, type, attr->mode);
+}
+
+
/**
* sysfs_create_file - create an attribute file for an object.
* @kobj: object we're creating for.
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 4779049..dac9383 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -23,30 +23,41 @@ static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
int i;
for (i = 0, attr = grp->attrs; *attr; i++, attr++)
- if (!grp->is_visible ||
- grp->is_visible(kobj, *attr, i))
- sysfs_hash_and_remove(dir_sd, (*attr)->name);
+ sysfs_hash_and_remove(dir_sd, (*attr)->name);
}
static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
- const struct attribute_group *grp)
+ const struct attribute_group *grp, int update)
{
struct attribute *const* attr;
int error = 0, i;
- for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++)
- if (!grp->is_visible ||
- grp->is_visible(kobj, *attr, i))
- error |=
- sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
+ for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
+ mode_t mode = 0;
+
+ /* in update mode, we're changing the permissions or
+ * visibility. Do this by first removing then
+ * re-adding (if required) the file */
+ if (update)
+ sysfs_hash_and_remove(dir_sd, (*attr)->name);
+ if (grp->is_visible) {
+ mode = grp->is_visible(kobj, *attr, i);
+ if (!mode)
+ continue;
+ }
+ error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
+ (*attr)->mode | mode);
+ if (unlikely(error))
+ break;
+ }
if (error)
remove_files(dir_sd, kobj, grp);
return error;
}
-int sysfs_create_group(struct kobject * kobj,
- const struct attribute_group * grp)
+static int internal_create_group(struct kobject *kobj, int update,
+ const struct attribute_group *grp)
{
struct sysfs_dirent *sd;
int error;
@@ -60,7 +71,7 @@ int sysfs_create_group(struct kobject * kobj,
} else
sd = kobj->sd;
sysfs_get(sd);
- error = create_files(sd, kobj, grp);
+ error = create_files(sd, kobj, grp, update);
if (error) {
if (grp->name)
sysfs_remove_subdir(sd);
@@ -69,6 +80,47 @@ int sysfs_create_group(struct kobject * kobj,
return error;
}
+/**
+ * sysfs_create_group - given a directory kobject, create an attribute group
+ * @kobj: The kobject to create the group on
+ * @grp: The attribute group to create
+ *
+ * This function creates a group for the first time. It will explicitly
+ * warn and error if any of the attribute files being created already exist.
+ *
+ * Returns 0 on success or error.
+ */
+int sysfs_create_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ return internal_create_group(kobj, 0, grp);
+}
+
+/**
+ * sysfs_update_group - given a directory kobject, create an attribute group
+ * @kobj: The kobject to create the group on
+ * @grp: The attribute group to create
+ *
+ * This function updates an attribute group. Unlike
+ * sysfs_create_group(), it will explicitly not warn or error if any
+ * of the attribute files being created already exist. Furthermore,
+ * if the visibility of the files has changed through the is_visible()
+ * callback, it will update the permissions and add or remove the
+ * relevant files.
+ *
+ * The primary use for this function is to call it after making a change
+ * that affects group visibility.
+ *
+ * Returns 0 on success or error.
+ */
+int sysfs_update_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ return internal_create_group(kobj, 1, grp);
+}
+
+
+
void sysfs_remove_group(struct kobject * kobj,
const struct attribute_group * grp)
{
@@ -95,4 +147,5 @@ void sysfs_remove_group(struct kobject * kobj,
EXPORT_SYMBOL_GPL(sysfs_create_group);
+EXPORT_SYMBOL_GPL(sysfs_update_group);
EXPORT_SYMBOL_GPL(sysfs_remove_group);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 52aaa8c..2915959 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -155,6 +155,8 @@ extern const struct file_operations sysfs_file_operations;
int sysfs_add_file(struct sysfs_dirent *dir_sd,
const struct attribute *attr, int type);
+int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
+ const struct attribute *attr, int type, mode_t amode);
/*
* bin.c
*/
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 0f388af..07d9c12 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -32,7 +32,7 @@ struct attribute {
struct attribute_group {
const char *name;
- int (*is_visible)(struct kobject *,
+ mode_t (*is_visible)(struct kobject *,
struct attribute *, int);
struct attribute **attrs;
};
@@ -105,6 +105,8 @@ void sysfs_remove_link(struct kobject *kobj, const char *name);
int __must_check sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp);
+int sysfs_update_group(struct kobject *kobj,
+ const struct attribute_group *grp);
void sysfs_remove_group(struct kobject *kobj,
const struct attribute_group *grp);
int sysfs_add_file_to_group(struct kobject *kobj,
--
1.5.4.3
--
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