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

From: Konrad Rzeszutek Wilk
Date: Mon Dec 05 2011 - 19:21:18 EST

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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
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
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Next message: Maxim Uvarov: "[PATCH] hpwd watchdog mark page executable"
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