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Re: [Xen-devel] [PATCH RFC V3 1/4] debugfs: Add support to print u32 array in debugfs



On Wed, Nov 30, 2011 at 02:29:39PM +0530, Raghavendra K T wrote:
> Add debugfs support to print u32-arrays in debugfs. Move the code from Xen to 
> debugfs
> to make the code common for other users as well.
> 
> Signed-off-by: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Suzuki Poulose <suzuki@xxxxxxxxxx>
> Signed-off-by: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>

Looks good to me.
> ---
> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
> index 7c0fedd..c8377fb 100644
> --- a/arch/x86/xen/debugfs.c
> +++ b/arch/x86/xen/debugfs.c
> @@ -19,107 +19,3 @@ struct dentry * __init xen_init_debugfs(void)
>       return d_xen_debug;
>  }
>  
> -struct array_data
> -{
> -     void *array;
> -     unsigned elements;
> -};
> -
> -static int u32_array_open(struct inode *inode, struct file *file)
> -{
> -     file->private_data = NULL;
> -     return nonseekable_open(inode, file);
> -}
> -
> -static size_t format_array(char *buf, size_t bufsize, const char *fmt,
> -                        u32 *array, unsigned array_size)
> -{
> -     size_t ret = 0;
> -     unsigned i;
> -
> -     for(i = 0; i < array_size; i++) {
> -             size_t len;
> -
> -             len = snprintf(buf, bufsize, fmt, array[i]);
> -             len++;  /* ' ' or '\n' */
> -             ret += len;
> -
> -             if (buf) {
> -                     buf += len;
> -                     bufsize -= len;
> -                     buf[-1] = (i == array_size-1) ? '\n' : ' ';
> -             }
> -     }
> -
> -     ret++;          /* \0 */
> -     if (buf)
> -             *buf = '\0';
> -
> -     return ret;
> -}
> -
> -static char *format_array_alloc(const char *fmt, u32 *array, unsigned 
> array_size)
> -{
> -     size_t len = format_array(NULL, 0, fmt, array, array_size);
> -     char *ret;
> -
> -     ret = kmalloc(len, GFP_KERNEL);
> -     if (ret == NULL)
> -             return NULL;
> -
> -     format_array(ret, len, fmt, array, array_size);
> -     return ret;
> -}
> -
> -static ssize_t u32_array_read(struct file *file, char __user *buf, size_t 
> len,
> -                           loff_t *ppos)
> -{
> -     struct inode *inode = file->f_path.dentry->d_inode;
> -     struct array_data *data = inode->i_private;
> -     size_t size;
> -
> -     if (*ppos == 0) {
> -             if (file->private_data) {
> -                     kfree(file->private_data);
> -                     file->private_data = NULL;
> -             }
> -
> -             file->private_data = format_array_alloc("%u", data->array, 
> data->elements);
> -     }
> -
> -     size = 0;
> -     if (file->private_data)
> -             size = strlen(file->private_data);
> -
> -     return simple_read_from_buffer(buf, len, ppos, file->private_data, 
> size);
> -}
> -
> -static int xen_array_release(struct inode *inode, struct file *file)
> -{
> -     kfree(file->private_data);
> -
> -     return 0;
> -}
> -
> -static const struct file_operations u32_array_fops = {
> -     .owner  = THIS_MODULE,
> -     .open   = u32_array_open,
> -     .release= xen_array_release,
> -     .read   = u32_array_read,
> -     .llseek = no_llseek,
> -};
> -
> -struct dentry *xen_debugfs_create_u32_array(const char *name, mode_t mode,
> -                                         struct dentry *parent,
> -                                         u32 *array, unsigned elements)
> -{
> -     struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
> -
> -     if (data == NULL)
> -             return NULL;
> -
> -     data->array = array;
> -     data->elements = elements;
> -
> -     return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
> -}
> diff --git a/arch/x86/xen/debugfs.h b/arch/x86/xen/debugfs.h
> index e281320..12ebf33 100644
> --- a/arch/x86/xen/debugfs.h
> +++ b/arch/x86/xen/debugfs.h
> @@ -3,8 +3,4 @@
>  
>  struct dentry * __init xen_init_debugfs(void);
>  
> -struct dentry *xen_debugfs_create_u32_array(const char *name, mode_t mode,
> -                                         struct dentry *parent,
> -                                         u32 *array, unsigned elements);
> -
>  #endif /* _XEN_DEBUGFS_H */
> diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
> index fc506e6..14a8961 100644
> --- a/arch/x86/xen/spinlock.c
> +++ b/arch/x86/xen/spinlock.c
> @@ -286,7 +286,7 @@ static int __init xen_spinlock_debugfs(void)
>       debugfs_create_u64("time_blocked", 0444, d_spin_debug,
>                          &spinlock_stats.time_blocked);
>  
> -     xen_debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
> +     debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
>                                    spinlock_stats.histo_spin_blocked, 
> HISTO_BUCKETS + 1);
>  
>       return 0;
> diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
> index 90f7657..df44ccf 100644
> --- a/fs/debugfs/file.c
> +++ b/fs/debugfs/file.c
> @@ -18,6 +18,7 @@
>  #include <linux/pagemap.h>
>  #include <linux/namei.h>
>  #include <linux/debugfs.h>
> +#include <linux/slab.h>
>  
>  static ssize_t default_read_file(struct file *file, char __user *buf,
>                                size_t count, loff_t *ppos)
> @@ -525,3 +526,130 @@ struct dentry *debugfs_create_blob(const char *name, 
> mode_t mode,
>       return debugfs_create_file(name, mode, parent, blob, &fops_blob);
>  }
>  EXPORT_SYMBOL_GPL(debugfs_create_blob);
> +
> +struct array_data {
> +     void *array;
> +     u32 elements;
> +};
> +
> +static int u32_array_open(struct inode *inode, struct file *file)
> +{
> +     file->private_data = NULL;
> +     return nonseekable_open(inode, file);
> +}
> +
> +static size_t format_array(char *buf, size_t bufsize, const char *fmt,
> +                        u32 *array, u32 array_size)
> +{
> +     size_t ret = 0;
> +     u32 i;
> +
> +     for (i = 0; i < array_size; i++) {
> +             size_t len;
> +
> +             len = snprintf(buf, bufsize, fmt, array[i]);
> +             len++;  /* ' ' or '\n' */
> +             ret += len;
> +
> +             if (buf) {
> +                     buf += len;
> +                     bufsize -= len;
> +                     buf[-1] = (i == array_size-1) ? '\n' : ' ';
> +             }
> +     }
> +
> +     ret++;          /* \0 */
> +     if (buf)
> +             *buf = '\0';
> +
> +     return ret;
> +}
> +
> +static char *format_array_alloc(const char *fmt, u32 *array,
> +                                             u32 array_size)
> +{
> +     size_t len = format_array(NULL, 0, fmt, array, array_size);
> +     char *ret;
> +
> +     ret = kmalloc(len, GFP_KERNEL);
> +     if (ret == NULL)
> +             return NULL;
> +
> +     format_array(ret, len, fmt, array, array_size);
> +     return ret;
> +}
> +
> +static ssize_t u32_array_read(struct file *file, char __user *buf, size_t 
> len,
> +                           loff_t *ppos)
> +{
> +     struct inode *inode = file->f_path.dentry->d_inode;
> +     struct array_data *data = inode->i_private;
> +     size_t size;
> +
> +     if (*ppos == 0) {
> +             if (file->private_data) {
> +                     kfree(file->private_data);
> +                     file->private_data = NULL;
> +             }
> +
> +             file->private_data = format_array_alloc("%u", data->array,
> +                                                           data->elements);
> +     }
> +
> +     size = 0;
> +     if (file->private_data)
> +             size = strlen(file->private_data);
> +
> +     return simple_read_from_buffer(buf, len, ppos,
> +                                     file->private_data, size);
> +}
> +
> +static int u32_array_release(struct inode *inode, struct file *file)
> +{
> +     kfree(file->private_data);
> +
> +     return 0;
> +}
> +
> +static const struct file_operations u32_array_fops = {
> +     .owner   = THIS_MODULE,
> +     .open    = u32_array_open,
> +     .release = u32_array_release,
> +     .read    = u32_array_read,
> +     .llseek  = no_llseek,
> +};
> +
> +/**
> + * debugfs_create_u32_array - create a debugfs file that is used to read u32
> + * array.
> + * @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.
> + * @array: u32 array that provides data.
> + * @elements: total number of elements in the array.
> + *
> + * This function creates a file in debugfs with the given name that exports
> + * @array as data. If the @mode variable is so set it can be read from.
> + * Writing is not supported. Seek within the file is also not supported.
> + * Once array is created its size can not be changed.
> + *
> + * The function returns a pointer to dentry on success. If debugfs is not
> + * enabled in the kernel, the value -%ENODEV will be returned.
> + */
> +struct dentry *debugfs_create_u32_array(const char *name, mode_t mode,
> +                                         struct dentry *parent,
> +                                         u32 *array, u32 elements)
> +{
> +     struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
> +
> +     if (data == NULL)
> +             return NULL;
> +
> +     data->array = array;
> +     data->elements = elements;
> +
> +     return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
> +}
> +EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
> diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
> index e7d9b20..253e2fb 100644
> --- a/include/linux/debugfs.h
> +++ b/include/linux/debugfs.h
> @@ -74,6 +74,10 @@ struct dentry *debugfs_create_blob(const char *name, 
> mode_t mode,
>                                 struct dentry *parent,
>                                 struct debugfs_blob_wrapper *blob);
>  
> +struct dentry *debugfs_create_u32_array(const char *name, mode_t mode,
> +                                     struct dentry *parent,
> +                                     u32 *array, u32 elements);
> +
>  bool debugfs_initialized(void);
>  
>  #else
> @@ -193,6 +197,13 @@ static inline bool debugfs_initialized(void)
>       return false;
>  }
>  
> +struct dentry *debugfs_create_u32_array(const char *name, mode_t mode,
> +                                     struct dentry *parent,
> +                                     u32 *array, u32 elements)
> +{
> +     return ERR_PTR(-ENODEV);
> +}
> +
>  #endif
>  
>  #endif
> 
> 
> _______________________________________________
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

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