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    Subject[PATCHv4 1/7] debugfs: add get/set for atomic types
    Date
    debugfs currently lack the ability to create attributes
    that set/get atomic_t values.

    This patch adds support for this through a new
    debugfs_create_atomic_t() function.

    Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    fs/debugfs/file.c | 42 ++++++++++++++++++++++++++++++++++++++++++
    include/linux/debugfs.h | 2 ++
    2 files changed, 44 insertions(+)

    diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
    index c5ca6ae..fa26d5b 100644
    --- a/fs/debugfs/file.c
    +++ b/fs/debugfs/file.c
    @@ -21,6 +21,7 @@
    #include <linux/debugfs.h>
    #include <linux/io.h>
    #include <linux/slab.h>
    +#include <linux/atomic.h>

    static ssize_t default_read_file(struct file *file, char __user *buf,
    size_t count, loff_t *ppos)
    @@ -403,6 +404,47 @@ struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
    }
    EXPORT_SYMBOL_GPL(debugfs_create_size_t);

    +static int debugfs_atomic_t_set(void *data, u64 val)
    +{
    + atomic_set((atomic_t *)data, val);
    + return 0;
    +}
    +static int debugfs_atomic_t_get(void *data, u64 *val)
    +{
    + *val = atomic_read((atomic_t *)data);
    + return 0;
    +}
    +DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
    + debugfs_atomic_t_set, "%llu\n");
    +DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%llu\n");
    +DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%llu\n");
    +
    +/**
    + * debugfs_create_atomic_t - create a debugfs file that is used to read and
    + * write an atomic_t value
    + * @name: a pointer to a string containing the name of the file to create.
    + * @mode: the permission that the file should have
    + * @parent: a pointer to the parent dentry for this file. This should be a
    + * directory dentry if set. If this parameter is %NULL, then the
    + * file will be created in the root of the debugfs filesystem.
    + * @value: a pointer to the variable that the file should read to and write
    + * from.
    + */
    +struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
    + struct dentry *parent, atomic_t *value)
    +{
    + /* if there are no write bits set, make read only */
    + if (!(mode & S_IWUGO))
    + return debugfs_create_file(name, mode, parent, value,
    + &fops_atomic_t_ro);
    + /* if there are no read bits set, make write only */
    + if (!(mode & S_IRUGO))
    + return debugfs_create_file(name, mode, parent, value,
    + &fops_atomic_t_wo);
    +
    + return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
    +}
    +EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);

    static ssize_t read_file_bool(struct file *file, char __user *user_buf,
    size_t count, loff_t *ppos)
    diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
    index 66c434f..51fea70 100644
    --- a/include/linux/debugfs.h
    +++ b/include/linux/debugfs.h
    @@ -79,6 +79,8 @@ struct dentry *debugfs_create_x64(const char *name, umode_t mode,
    struct dentry *parent, u64 *value);
    struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
    struct dentry *parent, size_t *value);
    +struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
    + struct dentry *parent, atomic_t *value);
    struct dentry *debugfs_create_bool(const char *name, umode_t mode,
    struct dentry *parent, u32 *value);

    --
    1.8.1.1


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