Continuation of recent upstream discussion [1] regarding user string
tokenization.
First, tokenize_user_input() is introduced to allow for splitting
specified user string into a sequence of integers. Makes use of
get_options() internally so the parsing logic is not duplicated.
With that done, redundant parts of the sound driver are removed.
Originally similar functionality was added for the SOF sound driver. As
more users are on the horizon, it is desirable to update existing
string_helpers code and provide a unified solution.
Changes in v3:
- relocated tokenize_user_input() implementation to string_helpers as
requested by Matthew
Changes in v2:
- reused get_options() so no parsing logic is duplicated
- simplified __user variant with help of memdup_user_nul()
Both suggested by Andy, thanks for thourough review
[1]: https://lore.kernel.org/alsa-devel/[email protected]/
Cezary Rojewski (2):
lib/string_helpers: Introduce tokenize_user_input()
ASoC: SOF: Remove strsplit_u32() and tokenize_input()
include/linux/string_helpers.h | 2 +
lib/string_helpers.c | 45 +++++++++++++++
sound/soc/sof/sof-client-probes.c | 93 ++++---------------------------
3 files changed, 59 insertions(+), 81 deletions(-)
--
2.25.1
Add new helper function to allow for splitting specified user string
into a sequence of integers. Internally it makes use of get_options() so
the returned sequence contains the integers extracted plus an additional
element that begins the sequence and specifies the integers count.
Suggested-by: Andy Shevchenko <[email protected]>
Signed-off-by: Cezary Rojewski <[email protected]>
---
include/linux/string_helpers.h | 2 ++
lib/string_helpers.c | 45 ++++++++++++++++++++++++++++++++++
2 files changed, 47 insertions(+)
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 4d72258d42fd..97583dae556f 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -21,6 +21,8 @@ enum string_size_units {
void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
char *buf, int len);
+int tokenize_user_input(const char __user *from, size_t count, int **tkns);
+
#define UNESCAPE_SPACE BIT(0)
#define UNESCAPE_OCTAL BIT(1)
#define UNESCAPE_HEX BIT(2)
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 5ed3beb066e6..f878afccab4c 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -131,6 +131,51 @@ void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
}
EXPORT_SYMBOL(string_get_size);
+/**
+ * tokenize_user_input - Split string into a sequence of integers
+ * @from: The user space buffer to read from
+ * @ppos: The current position in the buffer
+ * @count: The maximum number of bytes to read
+ * @tkns: Returned pointer to sequence of integers
+ *
+ * On success @tkns is allocated and initialized with a sequence of
+ * integers extracted from the @from plus an additional element that
+ * begins the sequence and specifies the integers count.
+ *
+ * Caller takes responsibility for freeing @tkns when it is no longer
+ * needed.
+ */
+int tokenize_user_input(const char __user *from, size_t count, int **tkns)
+{
+ int *ints, nints;
+ char *buf;
+ int ret = 0;
+
+ buf = memdup_user_nul(from, count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ get_options(buf, 0, &nints);
+ if (!nints) {
+ ret = -ENOENT;
+ goto free_buf;
+ }
+
+ ints = kcalloc(nints + 1, sizeof(*ints), GFP_KERNEL);
+ if (!ints) {
+ ret = -ENOMEM;
+ goto free_buf;
+ }
+
+ get_options(buf, nints + 1, ints);
+ *tkns = ints;
+
+free_buf:
+ kfree(buf);
+ return ret;
+}
+EXPORT_SYMBOL(tokenize_user_input);
+
static bool unescape_space(char **src, char **dst)
{
char *p = *dst, *q = *src;
--
2.25.1
Make use of global user input tokenization helper instead of the
internal one as both serve same purpose. With that, both strsplit_u32()
and tokenize_input() become unused so remove them.
Signed-off-by: Cezary Rojewski <[email protected]>
---
sound/soc/sof/sof-client-probes.c | 93 ++++---------------------------
1 file changed, 12 insertions(+), 81 deletions(-)
diff --git a/sound/soc/sof/sof-client-probes.c b/sound/soc/sof/sof-client-probes.c
index eb246b823461..e9c44831fae1 100644
--- a/sound/soc/sof/sof-client-probes.c
+++ b/sound/soc/sof/sof-client-probes.c
@@ -12,6 +12,7 @@
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
+#include <linux/string_helpers.h>
#include <sound/soc.h>
#include <sound/sof/header.h>
#include "sof-client.h"
@@ -410,79 +411,6 @@ static const struct snd_compress_ops sof_probes_compressed_ops = {
.copy = sof_probes_compr_copy,
};
-/**
- * strsplit_u32 - Split string into sequence of u32 tokens
- * @buf: String to split into tokens.
- * @delim: String containing delimiter characters.
- * @tkns: Returned u32 sequence pointer.
- * @num_tkns: Returned number of tokens obtained.
- */
-static int strsplit_u32(char *buf, const char *delim, u32 **tkns, size_t *num_tkns)
-{
- char *s;
- u32 *data, *tmp;
- size_t count = 0;
- size_t cap = 32;
- int ret = 0;
-
- *tkns = NULL;
- *num_tkns = 0;
- data = kcalloc(cap, sizeof(*data), GFP_KERNEL);
- if (!data)
- return -ENOMEM;
-
- while ((s = strsep(&buf, delim)) != NULL) {
- ret = kstrtouint(s, 0, data + count);
- if (ret)
- goto exit;
- if (++count >= cap) {
- cap *= 2;
- tmp = krealloc(data, cap * sizeof(*data), GFP_KERNEL);
- if (!tmp) {
- ret = -ENOMEM;
- goto exit;
- }
- data = tmp;
- }
- }
-
- if (!count)
- goto exit;
- *tkns = kmemdup(data, count * sizeof(*data), GFP_KERNEL);
- if (!(*tkns)) {
- ret = -ENOMEM;
- goto exit;
- }
- *num_tkns = count;
-
-exit:
- kfree(data);
- return ret;
-}
-
-static int tokenize_input(const char __user *from, size_t count,
- loff_t *ppos, u32 **tkns, size_t *num_tkns)
-{
- char *buf;
- int ret;
-
- buf = kmalloc(count + 1, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- ret = simple_write_to_buffer(buf, count, ppos, from, count);
- if (ret != count) {
- ret = ret >= 0 ? -EIO : ret;
- goto exit;
- }
-
- buf[count] = '\0';
- ret = strsplit_u32(buf, ",", tkns, num_tkns);
-exit:
- kfree(buf);
- return ret;
-}
-
static ssize_t sof_probes_dfs_points_read(struct file *file, char __user *to,
size_t count, loff_t *ppos)
{
@@ -548,8 +476,8 @@ sof_probes_dfs_points_write(struct file *file, const char __user *from,
struct sof_probes_priv *priv = cdev->data;
struct device *dev = &cdev->auxdev.dev;
struct sof_probe_point_desc *desc;
- size_t num_tkns, bytes;
- u32 *tkns;
+ size_t bytes;
+ u32 num_tkns, *tkns;
int ret, err;
if (priv->extractor_stream_tag == SOF_PROBES_INVALID_NODE_ID) {
@@ -557,16 +485,18 @@ sof_probes_dfs_points_write(struct file *file, const char __user *from,
return -ENOENT;
}
- ret = tokenize_input(from, count, ppos, &tkns, &num_tkns);
+ ret = tokenize_user_input(from, count, (int **)&tkns);
if (ret < 0)
return ret;
+
+ num_tkns = *tkns;
bytes = sizeof(*tkns) * num_tkns;
if (!num_tkns || (bytes % sizeof(*desc))) {
ret = -EINVAL;
goto exit;
}
- desc = (struct sof_probe_point_desc *)tkns;
+ desc = (struct sof_probe_point_desc *)&tkns[1];
ret = pm_runtime_resume_and_get(dev);
if (ret < 0 && ret != -EACCES) {
@@ -603,8 +533,7 @@ sof_probes_dfs_points_remove_write(struct file *file, const char __user *from,
struct sof_client_dev *cdev = file->private_data;
struct sof_probes_priv *priv = cdev->data;
struct device *dev = &cdev->auxdev.dev;
- size_t num_tkns;
- u32 *tkns;
+ u32 num_tkns, *tkns;
int ret, err;
if (priv->extractor_stream_tag == SOF_PROBES_INVALID_NODE_ID) {
@@ -612,9 +541,11 @@ sof_probes_dfs_points_remove_write(struct file *file, const char __user *from,
return -ENOENT;
}
- ret = tokenize_input(from, count, ppos, &tkns, &num_tkns);
+ ret = tokenize_user_input(from, count, (int **)&tkns);
if (ret < 0)
return ret;
+
+ num_tkns = *tkns;
if (!num_tkns) {
ret = -EINVAL;
goto exit;
@@ -626,7 +557,7 @@ sof_probes_dfs_points_remove_write(struct file *file, const char __user *from,
goto exit;
}
- ret = sof_probes_points_remove(cdev, tkns, num_tkns);
+ ret = sof_probes_points_remove(cdev, &tkns[1], num_tkns);
if (!ret)
ret = count;
--
2.25.1
On Thu, Sep 1, 2022 at 8:40 PM Cezary Rojewski
<[email protected]> wrote:
>
> Add new helper function to allow for splitting specified user string
> into a sequence of integers. Internally it makes use of get_options() so
> the returned sequence contains the integers extracted plus an additional
> element that begins the sequence and specifies the integers count.
Thanks! In general it looks good to me, but a few minor comments below.
...
> +int tokenize_user_input(const char __user *from, size_t count, int **tkns);
Not sure how I can deduct from the name what function is actually
doing. Suggested new name: int_array_parse_user().
int int_array_parse_user(const char __user *from, size_t count, int **array);
(Note that we have _user suffix for many APIs in the kernel that does
interact with user space memory)
...
> + * @tkns: Returned pointer to sequence of integers
array
...
If you are okay with this, you may add my
Reviewed-by: Andy Shevchenko <[email protected]>
--
With Best Regards,
Andy Shevchenko
On Thu, Sep 1, 2022 at 8:40 PM Cezary Rojewski
<[email protected]> wrote:
>
> Make use of global user input tokenization helper instead of the
> internal one as both serve same purpose. With that, both strsplit_u32()
the same
> and tokenize_input() become unused so remove them.
...
> #include <linux/debugfs.h>
> #include <linux/module.h>
> #include <linux/pm_runtime.h>
> +#include <linux/string_helpers.h>
I believe either blank line needs to be here (to split the sound / SOF
group of headers) or this should be put after 'so*'-ones
> #include <sound/soc.h>
> #include <sound/sof/header.h>
> #include "sof-client.h"
...
> struct sof_probes_priv *priv = cdev->data;
> struct device *dev = &cdev->auxdev.dev;
> struct sof_probe_point_desc *desc;
> - size_t num_tkns, bytes;
> - u32 *tkns;
> + size_t bytes;
> + u32 num_tkns, *tkns;
I would expect a longer line first.
> int ret, err;
...
With the above addressed
Reviewed-by: Andy Shevchenko <[email protected]>
--
With Best Regards,
Andy Shevchenko
On 2022-09-01 9:34 PM, Andy Shevchenko wrote:
> On Thu, Sep 1, 2022 at 8:40 PM Cezary Rojewski
> <[email protected]> wrote:
...
>> +int tokenize_user_input(const char __user *from, size_t count, int **tkns);
>
> Not sure how I can deduct from the name what function is actually
> doing. Suggested new name: int_array_parse_user().
>
> int int_array_parse_user(const char __user *from, size_t count, int **array);
>
> (Note that we have _user suffix for many APIs in the kernel that does
> interact with user space memory)
That's why I've added '_user_' in the middle! Anyway, I guess the
expectation is that it's a suffix - precisely at the end of the name.
Could we reorder it a bit: "parse_int_array_user"?
>> + * @tkns: Returned pointer to sequence of integers
>
> array
Ack.
> If you are okay with this, you may add my
> Reviewed-by: Andy Shevchenko <[email protected]>
>
On Fri, Sep 2, 2022 at 10:46 AM Cezary Rojewski
<[email protected]> wrote:
> On 2022-09-01 9:34 PM, Andy Shevchenko wrote:
> > On Thu, Sep 1, 2022 at 8:40 PM Cezary Rojewski
> > <[email protected]> wrote:
...
> >> +int tokenize_user_input(const char __user *from, size_t count, int **tkns);
> >
> > Not sure how I can deduct from the name what function is actually
> > doing. Suggested new name: int_array_parse_user().
> >
> > int int_array_parse_user(const char __user *from, size_t count, int **array);
> >
> > (Note that we have _user suffix for many APIs in the kernel that does
> > interact with user space memory)
>
> That's why I've added '_user_' in the middle! Anyway, I guess the
> expectation is that it's a suffix - precisely at the end of the name.
>
> Could we reorder it a bit: "parse_int_array_user"?
Most of the exported functions that have 'parse' word, have it after
namespace, but in this case there is no dedicated namespace and it
also will be in alignment with parse_options_str. That said, go for
it.
--
With Best Regards,
Andy Shevchenko
On 2022-09-01 9:38 PM, Andy Shevchenko wrote:
> On Thu, Sep 1, 2022 at 8:40 PM Cezary Rojewski
> <[email protected]> wrote:
>>
>> Make use of global user input tokenization helper instead of the
>> internal one as both serve same purpose. With that, both strsplit_u32()
>
> the same
>
>> and tokenize_input() become unused so remove them.
...
>> #include <linux/debugfs.h>
>> #include <linux/module.h>
>> #include <linux/pm_runtime.h>
>> +#include <linux/string_helpers.h>
>
> I believe either blank line needs to be here (to split the sound / SOF
> group of headers) or this should be put after 'so*'-ones
Newline it is then.
>> #include <sound/soc.h>
>> #include <sound/sof/header.h>
>> #include "sof-client.h"
...
>> struct sof_probes_priv *priv = cdev->data;
>> struct device *dev = &cdev->auxdev.dev;
>> struct sof_probe_point_desc *desc;
>> - size_t num_tkns, bytes;
>> - u32 *tkns;
>> + size_t bytes;
>> + u32 num_tkns, *tkns;
>
> I would expect a longer line first.
Ack.
> With the above addressed
> Reviewed-by: Andy Shevchenko <[email protected]>
>