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sysfs: Remove sysfs_get/put_active_two

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It turns out that holding an active reference on a directory is
pointless.  The purpose of the active references are to allows us to
block when removing sysfs entries that have custom methods so we don't
remove modules while running modular code and to keep those custom
methods from accessing data structures after the files have been
removed.  Further sysfs_remove_dir remove all elements in the
directory before removing the directory itself, so there is no chance
we will remove a directory with active children.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Eric W. Biederman
2010-02-11 15:18:38 -08:00
committed by Greg Kroah-Hartman
parent 3c31f07ad0
commit e72ceb8cca
4 changed files with 38 additions and 77 deletions
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18
fs/sysfs/file.c
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@@ -85,13 +85,13 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer
return -ENOMEM;
/* need attr_sd for attr and ops, its parent for kobj */
if (!sysfs_get_active_two(attr_sd))
if (!sysfs_get_active(attr_sd))
return -ENODEV;
buffer->event = atomic_read(&attr_sd->s_attr.open->event);
count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
sysfs_put_active_two(attr_sd);
sysfs_put_active(attr_sd);
/*
* The code works fine with PAGE_SIZE return but it's likely to
@@ -203,12 +203,12 @@ flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t
int rc;
/* need attr_sd for attr and ops, its parent for kobj */
if (!sysfs_get_active_two(attr_sd))
if (!sysfs_get_active(attr_sd))
return -ENODEV;
rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count);
sysfs_put_active_two(attr_sd);
sysfs_put_active(attr_sd);
return rc;
}
@@ -344,7 +344,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
memmove(last_sysfs_file, p, strlen(p) + 1);
/* need attr_sd for attr and ops, its parent for kobj */
if (!sysfs_get_active_two(attr_sd))
if (!sysfs_get_active(attr_sd))
return -ENODEV;
/* every kobject with an attribute needs a ktype assigned */
@@ -393,13 +393,13 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
goto err_free;
/* open succeeded, put active references */
sysfs_put_active_two(attr_sd);
sysfs_put_active(attr_sd);
return 0;
err_free:
kfree(buffer);
err_out:
sysfs_put_active_two(attr_sd);
sysfs_put_active(attr_sd);
return error;
}
@@ -437,12 +437,12 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
struct sysfs_open_dirent *od = attr_sd->s_attr.open;
/* need parent for the kobj, grab both */
if (!sysfs_get_active_two(attr_sd))
if (!sysfs_get_active(attr_sd))
goto trigger;
poll_wait(filp, &od->poll, wait);
sysfs_put_active_two(attr_sd);
sysfs_put_active(attr_sd);
if (buffer->event != atomic_read(&od->event))
goto trigger;