Re: [PATCH v2 2/7] sysfs.h: add ATTRIBUTE_GROUPS() macro
From: Oliver Schinagl
Date: Thu Jul 11 2013 - 16:09:25 EST
On 07/11/13 19:06, Greg Kroah-Hartman wrote:
On Thu, Jul 11, 2013 at 01:58:29PM +0200, Oliver Schinagl wrote:
On 11-07-13 02:36, Greg Kroah-Hartman wrote:
To make it easier for driver subsystems to work with attribute groups,
create the ATTRIBUTE_GROUPS macro to remove some of the repetitive
typing for the most common use for attribute groups.
But binary groups are discriminated against :(
Yes, as they are "rarer" by far, as they should be. binary sysfs files
should almost never be used, as they are only "pass-through" files to
the hardware, so I want to see you do more work in order to use them, as
they should not be created lightly.
I guess I can see a valid reason here, but they are only helper macro's
making life easier for people who do need to use these and are on par
with the non-binary versions. And we already have quite some binary
attributes, probably far less then normal ones :)
Anyway, wouldn't all users be reviewed anyway? But I guess it's a small
safety net to make it not TOO easy.
The attached patch should help here.
Can you give me an example of using these macros? I seem to be lost in
them somehow, or maybe my morning coffee just hasn't kicked in...
Yeah, I kinda added the whole shebang there :) I was trying being helpful :(
I suppose one more additional helper wouldn't be bad to have:
#define ATTRIBUTE_(BIN_)GROUPS_R[O/W](_name(, _size)) \
ATTRIBUTE_(BIN_)ATTR_R[O/W](_name, _size); \
ATTRIBUTE_(BIN_)GROUPS(_name)
Would that ever be needed?
Of ourse, by the lazy :)
I think now you create an attribute in a group as this (with this patch):
ATTRIBUTE_ATTR_RO(name, SIZE);
ATTRIBUTE_GROUPS(name);
.group = name;
After that last addition, you'd simply do:
ATTRIBUTE_GROUPS_RO(name);
.group = name;
saves a whole line :)
>From 003ab7a74ff689daa6934e7bc50c498b2d35a1cc Mon Sep 17 00:00:00 2001
From: Oliver Schinagl <oliver@xxxxxxxxxxx>
Date: Thu, 11 Jul 2013 13:48:18 +0200
Subject: [PATCH] sysfs: add more helper macro's for (bin_)attribute(_groups)
With the recent changes to sysfs there's various helper macro's.
However there's no RW, RO BIN_ helper macro's. This patch adds them.
Additionally there are no BIN_ group helpers so there's that aswell
Moreso, if both bin and normal attribute groups are used, there's a
simple helper for that, though the naming code be better. _TXT_ for the
show/store ones and neither TXT or BIN for both, but that would change
things to extensivly.
Finally there's also helpers for ATTRIBUTE_ATTRS.
After this patch, create default attributes can be as easy as:
ATTRIBUTE_(BIN_)ATTR_RO(name, SIZE);
ATTRIBUTE_BIN_GROUPS(name);
Signed-off-by: Oliver Schinagl <oliver@xxxxxxxxxxx>
---
include/linux/sysfs.h | 96 ++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 84 insertions(+), 12 deletions(-)
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 2c3b6a3..0ebed11 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -17,6 +17,7 @@
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/kobject_ns.h>
+#include <linux/stat.h>
#include <linux/atomic.h>
struct kobject;
@@ -94,15 +95,32 @@ struct attribute_group {
#define __ATTR_IGNORE_LOCKDEP __ATTR
#endif
-#define ATTRIBUTE_GROUPS(name) \
-static const struct attribute_group name##_group = { \
- .attrs = name##_attrs, \
+#define __ATTRIBUTE_GROUPS(_name) \
+static const struct attribute_group *_name##_groups[] = { \
+ &_name##_group, \
+ NULL, \
+}
+
+#define ATTRIBUTE_GROUPS(_name) \
+static const struct attribute_group _name##_group = { \
+ .attrs = _name##_attrs, \
}; \
-static const struct attribute_group *name##_groups[] = { \
- &name##_group, \
+__ATTRIBUTE_GROUPS(_name)
+
+#define __ATTRIBUTE_ATTRS(_name) \
+struct bin_attribute *_name##_attrs[] = { \
typo here, scrap bin_ copy paste fail!
+ &_name##_attr, \
NULL, \
}
+#define ATTRIBUTE_ATTR_RO(_name, _size) \
+struct attribute _name##_attr = __ATTR_RO(_name, _size); \
+__ATTRIBUTE_ATTRS(_name)
+
+#define ATTRIBUTE_ATTR_RW(_name, _size) \
+struct attribute _name##_attr = __ATTR_RW(_name, _size); \
+__ATTRIBUTE_ATTRS(_name)
What do these two help out with? "attribute attribute read-write" seems
a bit "clunky", don't you think? :)
I aggree, but I tried to stick with the ATTRIBUTE_GROUP naming and
that's the best I could come up with.
Unless I completely misunderstood (which isn't all that unlikely) the
following is needed to create a group using a .group.
So you pass group an array of attribute_group pointers. The
ATTRIBUTE_GROUPS helps there, right? It saves the typing of creating the
array of groups and adding groups to that.
So a group consists of an array of attributes if I understood right and
that array needs to be filled with pointers attributes? well those
ATTRIBUTE_ATTR's do just that. Granted, maybe the naming is poor, but
just ATTRS() felt to short.
+
#define attr_name(_attr) (_attr).attr.name
struct file;
@@ -132,15 +150,69 @@ struct bin_attribute {
*/
#define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)
-/* macro to create static binary attributes easier */
-#define BIN_ATTR(_name, _mode, _read, _write, _size) \
-struct bin_attribute bin_attr_##_name = { \
- .attr = {.name = __stringify(_name), .mode = _mode }, \
- .read = _read, \
- .write = _write, \
- .size = _size, \
+/* macros to create static binary attributes easier */
+#define __BIN_ATTR(_name, _mode, _read, _write, _size) { \
+ .attr = { .name = __stringify(_name), .mode = _mode }, \
+ .read = _read, \
+ .write = _write, \
+ .size = _size, \
+}
+
+#define __BIN_ATTR_RO(_name, _size) { \
+ .attr = { .name = __stringify(_name), .mode = S_IRUGO }, \
+ .read = _name##_read, \
+ .size = _size, \
+}
+
+#define __BIN_ATTR_RW(_name, _size) __BIN_ATTR(_name, \
+ (S_IWUSR | S_IRUGO), _name##_read, \
+ _name##_write)
+
+#define __BIN_ATTR_NULL __ATTR_NULL
+
+#define BIN_ATTR(_name, _mode, _read, _write, _size) \
+struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read, \
+ _write, _size)
+
+#define BIN_RO_ATTR(_name, _size) \
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)
+
+#define BIN_RW_ATTR(_name, _size) \
+struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
To be consistent, these shoudl be BIN_ATTR_RO and BIN_ATTR_RW, right?
Yes, I too did this before morning coffee, and I don't drink coffee!
These all look fine to me, thanks.
It's these that I'm confused about:
+
+#define __ATTRIBUTE_BIN_GROUPS(_name) \
+static const struct attribute_group *_name##_bin_groups[] = { \
+ &_name##_bin_group, \
+ NULL, \
}
This is just a helper for the ones below.
+#define ATTRIBUTE_BIN_GROUPS(_name) \
+static const struct attribute_group _name##_bin_group = { \
+ .bin_attrs = _name##_bin_attrs, \
+}; \
+__ATTRIBUTE_BIN_GROUPS(_name)
This is the equiv. of ATTRIBUTE_GROUPS(_name) which creates an attribute
group, with only a binary attribute instead.
+
+#define ATTRIBUTE_FULL_GROUPS(_name) \
+static const struct attribute_group _name##_full_group = { \
+ .attrs = _name##_attrs, \
+ .bin_attrs = _name##_bin_attrs, \
+}; \
+__ATTRIBUTE_GROUPS(_name); __ATTRIBUTE_BIN_GROUPS(_name)
This one probably should go, it defines both, and since binaries should
be used cautiously, it's not really needed I guess.
+
+#define __ATTRIBUTE_BIN_ATTRS(_name) \
+struct bin_attribute *_name##_bin_attrs[] = { \
+ &_name##_bin_attr, \
+ NULL, \
+}
Helper macro again for below
+
+#define ATTRIBUTE_BIN_ATTR_RO(_name, _size) \
+struct bin_attribute _name##_bin_attr = __BIN_ATTR_RO(_name, _size); \
+__ATTRIBUTE_BIN_ATTRS(_name)
+
+#define ATTRIBUTE_BIN_ATTR_RW(_name, _size) \
+struct bin_attribute _name##_bin_attr = __BIN_ATTR_RW(_name, _size); \
+__ATTRIBUTE_BIN_ATTRS(_name)
These I guess are the equivialent what ATTRIBUTE_GROUP is for groups,
but now for the attributes that go in groups?
Can you show me how these would be used in a real-world example?
Well my real world is currently limited by my own driver. If I may copy
paste from there:
ATTRIBUTE_BIN_ATTR_RO(sunxi_sid, SID_SIZE);
ATTRIBUTE_BIN_GROUPS(sunxi_sid);
static struct platform_driver sunxi_sid_driver = {
.probe = sunxi_sid_probe,
.remove = sunxi_sid_remove,
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
.of_match_table = sunxi_sid_of_match,
.groups = sunxi_sid_bin_groups,
},
};
module_platform_driver(sunxi_sid_driver);
But if you say, you want to be a little less complete, we can drop
ATTRIBUTE_BIN_ATTR_R[OW]() forcing you to do this instead:
struct bin_attribute sunxi_sid_bin_attr = __BIN_ATTR_RO(eeprom, SID_SIZE);
struct bin_attribute *sunxi_sid_bin_attrs[] = {
&sunxi_sid_bin_attr,
NULL,
};
Which requires some manual labor yet still has the __BIN_ATTR_R[OW]
macro's to help with some of the more tedious work and allowing you to
name the binary attributes nicer?
thanks,
Sorry if I sound a little confusing, it made a lot of sense this morning :(
Oliver
greg k-h
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