USB: gadget: f_mass_storage: use static attribute groups for sysfs entries
Instead of manual device_create_file() and device_remove_file() calls, assign the static attribute groups to the lun device to register. The RO or RW permissions for some entries are decided in is_visible callback. This simplifies the code (also the logic) and avoids the possible races, too. Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Takashi Iwai
Greg Kroah-Hartman
parent
c60b89aa36
commit
c7b364f7dd
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@ -2624,13 +2624,10 @@ static ssize_t file_store(struct device *dev, struct device_attribute *attr,
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return fsg_store_file(curlun, filesem, buf, count);
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}
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static DEVICE_ATTR_RW(ro);
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static DEVICE_ATTR_RW(nofua);
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static DEVICE_ATTR_RW(file);
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static struct device_attribute dev_attr_ro_cdrom = __ATTR_RO(ro);
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static struct device_attribute dev_attr_file_nonremovable = __ATTR_RO(file);
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/* mode wil be set in fsg_lun_attr_is_visible() */
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static DEVICE_ATTR(ro, 0, ro_show, ro_store);
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static DEVICE_ATTR(file, 0, file_show, file_store);
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/****************************** FSG COMMON ******************************/
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@ -2745,40 +2742,10 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n)
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}
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EXPORT_SYMBOL_GPL(fsg_common_set_num_buffers);
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static inline void fsg_common_remove_sysfs(struct fsg_lun *lun)
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{
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device_remove_file(&lun->dev, &dev_attr_nofua);
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/*
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* device_remove_file() =>
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*
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* here the attr (e.g. dev_attr_ro) is only used to be passed to:
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*
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* sysfs_remove_file() =>
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*
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* here e.g. both dev_attr_ro_cdrom and dev_attr_ro are in
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* the same namespace and
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* from here only attr->name is passed to:
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*
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* sysfs_hash_and_remove()
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*
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* attr->name is the same for dev_attr_ro_cdrom and
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* dev_attr_ro
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* attr->name is the same for dev_attr_file and
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* dev_attr_file_nonremovable
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*
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* so we don't differentiate between removing e.g. dev_attr_ro_cdrom
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* and dev_attr_ro
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*/
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device_remove_file(&lun->dev, &dev_attr_ro);
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device_remove_file(&lun->dev, &dev_attr_file);
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}
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void fsg_common_remove_lun(struct fsg_lun *lun, bool sysfs)
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{
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if (sysfs) {
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fsg_common_remove_sysfs(lun);
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if (sysfs)
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device_unregister(&lun->dev);
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}
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fsg_lun_close(lun);
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kfree(lun);
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}
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@ -2877,42 +2844,36 @@ int fsg_common_set_cdev(struct fsg_common *common,
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}
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EXPORT_SYMBOL_GPL(fsg_common_set_cdev);
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static inline int fsg_common_add_sysfs(struct fsg_common *common,
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struct fsg_lun *lun)
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static struct attribute *fsg_lun_dev_attrs[] = {
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&dev_attr_ro.attr,
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&dev_attr_file.attr,
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&dev_attr_nofua.attr,
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NULL
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};
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static umode_t fsg_lun_dev_is_visible(struct kobject *kobj,
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struct attribute *attr, int idx)
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{
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int rc;
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struct device *dev = kobj_to_dev(kobj);
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struct fsg_lun *lun = fsg_lun_from_dev(dev);
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rc = device_register(&lun->dev);
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if (rc) {
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put_device(&lun->dev);
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return rc;
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}
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rc = device_create_file(&lun->dev,
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lun->cdrom
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? &dev_attr_ro_cdrom
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: &dev_attr_ro);
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if (rc)
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goto error;
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rc = device_create_file(&lun->dev,
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lun->removable
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? &dev_attr_file
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: &dev_attr_file_nonremovable);
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if (rc)
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goto error;
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rc = device_create_file(&lun->dev, &dev_attr_nofua);
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if (rc)
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goto error;
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return 0;
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error:
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/* removing nonexistent files is a no-op */
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fsg_common_remove_sysfs(lun);
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device_unregister(&lun->dev);
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return rc;
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if (attr == &dev_attr_ro.attr)
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return lun->cdrom ? S_IRUGO : (S_IWUSR | S_IRUGO);
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if (attr == &dev_attr_file.attr)
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return lun->removable ? (S_IWUSR | S_IRUGO) : S_IRUGO;
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return attr->mode;
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}
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static const struct attribute_group fsg_lun_dev_group = {
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.attrs = fsg_lun_dev_attrs,
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.is_visible = fsg_lun_dev_is_visible,
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};
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static const struct attribute_group *fsg_lun_dev_groups[] = {
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&fsg_lun_dev_group,
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NULL
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};
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int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
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unsigned int id, const char *name,
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const char **name_pfx)
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@ -2949,13 +2910,15 @@ int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
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} else {
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lun->dev.release = fsg_lun_release;
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lun->dev.parent = &common->gadget->dev;
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lun->dev.groups = fsg_lun_dev_groups;
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dev_set_drvdata(&lun->dev, &common->filesem);
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dev_set_name(&lun->dev, "%s", name);
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lun->name = dev_name(&lun->dev);
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rc = fsg_common_add_sysfs(common, lun);
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rc = device_register(&lun->dev);
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if (rc) {
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pr_info("failed to register LUN%d: %d\n", id, rc);
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put_device(&lun->dev);
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goto error_sysfs;
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}
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}
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@ -2988,10 +2951,8 @@ int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
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return 0;
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error_lun:
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if (common->sysfs) {
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fsg_common_remove_sysfs(lun);
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if (common->sysfs)
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device_unregister(&lun->dev);
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}
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fsg_lun_close(lun);
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common->luns[id] = NULL;
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error_sysfs:
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@ -3077,8 +3038,6 @@ static void fsg_common_release(struct kref *ref)
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struct fsg_lun *lun = *lun_it;
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if (!lun)
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continue;
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if (common->sysfs)
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fsg_common_remove_sysfs(lun);
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fsg_lun_close(lun);
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if (common->sysfs)
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device_unregister(&lun->dev);
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