Re: [PATCH 1/3] dmatest: make module parameters writable

From: Andy Shevchenko
Date: Wed Jul 31 2013 - 10:28:30 EST

On Tue, 2013-07-23 at 18:36 +0300, Andy Shevchenko wrote:
> The debugfs interface brought a copy of the test case parameters. This makes
> different set of values under /sys/module/dmatest/parameters/ and
> /sys/kernel/debug/dmatest/. The user might be confused by the divergence of
> values.
>
> The proposed solution in this patch is to make module parameters writable and
> remove them from the debugfs. Though we're still using debugfs to control test
> runner and getting results.
>
> Documentation part is updated accordingly.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Suggested-by: Dan Williams <djbw@xxxxxx>

Dan, do you have any comments against this series?
I'd like to have this incorporated into v3.12.


> ---
> Documentation/dmatest.txt | 15 +++--
> drivers/dma/dmatest.c | 159 ++++++----------------------------------------
> 2 files changed, 28 insertions(+), 146 deletions(-)
>
> diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt
> index 132a094..a2b5663 100644
> --- a/Documentation/dmatest.txt
> +++ b/Documentation/dmatest.txt
> @@ -16,15 +16,16 @@ be built as module or inside kernel. Let's consider those cases.
> Part 2 - When dmatest is built as a module...
>
> After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest
> -folder with nodes will be created. They are the same as module parameters with
> -addition of the 'run' node that controls run and stop phases of the test.
> +folder with nodes will be created. There are two important files located. First
> +is the 'run' node that controls run and stop phases of the test, and the second
> +one, 'results', is used to get the test case results.
>
> Note that in this case test will not run on load automatically.
>
> Example of usage:
> - % echo dma0chan0 > /sys/kernel/debug/dmatest/channel
> - % echo 2000 > /sys/kernel/debug/dmatest/timeout
> - % echo 1 > /sys/kernel/debug/dmatest/iterations
> + % echo dma0chan0 > /sys/module/dmatest/parameters/channel
> + % echo 2000 > /sys/module/dmatest/parameters/timeout
> + % echo 1 > /sys/module/dmatest/parameters/iterations
> % echo 1 > /sys/kernel/debug/dmatest/run
>
> Hint: available channel list could be extracted by running the following
> @@ -55,8 +56,8 @@ for the first performed test. After user gets a control, the test could be
> re-run with the same or different parameters. For the details see the above
> section "Part 2 - When dmatest is built as a module..."
>
> -In both cases the module parameters are used as initial values for the test case.
> -You always could check them at run-time by running
> +In both cases the module parameters are used as the actual values for the test
> +case. You always could check them at run-time by running
> % grep -H . /sys/module/dmatest/parameters/*
>
> Part 4 - Gathering the test results
> diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
> index e88ded2..91716f4 100644
> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -25,44 +25,46 @@
> #include <linux/seq_file.h>
>
> static unsigned int test_buf_size = 16384;
> -module_param(test_buf_size, uint, S_IRUGO);
> +module_param(test_buf_size, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");
>
> static char test_channel[20];
> -module_param_string(channel, test_channel, sizeof(test_channel), S_IRUGO);
> +module_param_string(channel, test_channel, sizeof(test_channel),
> + S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");
>
> static char test_device[20];
> -module_param_string(device, test_device, sizeof(test_device), S_IRUGO);
> +module_param_string(device, test_device, sizeof(test_device),
> + S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");
>
> static unsigned int threads_per_chan = 1;
> -module_param(threads_per_chan, uint, S_IRUGO);
> +module_param(threads_per_chan, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(threads_per_chan,
> "Number of threads to start per channel (default: 1)");
>
> static unsigned int max_channels;
> -module_param(max_channels, uint, S_IRUGO);
> +module_param(max_channels, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(max_channels,
> "Maximum number of channels to use (default: all)");
>
> static unsigned int iterations;
> -module_param(iterations, uint, S_IRUGO);
> +module_param(iterations, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(iterations,
> "Iterations before stopping test (default: infinite)");
>
> static unsigned int xor_sources = 3;
> -module_param(xor_sources, uint, S_IRUGO);
> +module_param(xor_sources, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(xor_sources,
> "Number of xor source buffers (default: 3)");
>
> static unsigned int pq_sources = 3;
> -module_param(pq_sources, uint, S_IRUGO);
> +module_param(pq_sources, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(pq_sources,
> "Number of p+q source buffers (default: 3)");
>
> static int timeout = 3000;
> -module_param(timeout, uint, S_IRUGO);
> +module_param(timeout, uint, S_IRUGO | S_IWUSR);
> MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
> "Pass -1 for infinite timeout");
>
> @@ -193,7 +195,6 @@ struct dmatest_info {
>
> /* debugfs related stuff */
> struct dentry *root;
> - struct dmatest_params dbgfs_params;
>
> /* Test results */
> struct list_head results;
> @@ -1007,7 +1008,15 @@ static int __restart_threaded_test(struct dmatest_info *info, bool run)
> result_free(info, NULL);
>
> /* Copy test parameters */
> - memcpy(params, &info->dbgfs_params, sizeof(*params));
> + params->buf_size = test_buf_size;
> + strlcpy(params->channel, strim(test_channel), sizeof(params->channel));
> + strlcpy(params->device, strim(test_device), sizeof(params->device));
> + params->threads_per_chan = threads_per_chan;
> + params->max_channels = max_channels;
> + params->iterations = iterations;
> + params->xor_sources = xor_sources;
> + params->pq_sources = pq_sources;
> + params->timeout = timeout;
>
> /* Run test with new parameters */
> return __run_threaded_test(info);
> @@ -1029,71 +1038,6 @@ static bool __is_threaded_test_run(struct dmatest_info *info)
> return false;
> }
>
> -static ssize_t dtf_write_string(void *to, size_t available, loff_t *ppos,
> - const void __user *from, size_t count)
> -{
> - char tmp[20];
> - ssize_t len;
> -
> - len = simple_write_to_buffer(tmp, sizeof(tmp) - 1, ppos, from, count);
> - if (len >= 0) {
> - tmp[len] = '\0';
> - strlcpy(to, strim(tmp), available);
> - }
> -
> - return len;
> -}
> -
> -static ssize_t dtf_read_channel(struct file *file, char __user *buf,
> - size_t count, loff_t *ppos)
> -{
> - struct dmatest_info *info = file->private_data;
> - return simple_read_from_buffer(buf, count, ppos,
> - info->dbgfs_params.channel,
> - strlen(info->dbgfs_params.channel));
> -}
> -
> -static ssize_t dtf_write_channel(struct file *file, const char __user *buf,
> - size_t size, loff_t *ppos)
> -{
> - struct dmatest_info *info = file->private_data;
> - return dtf_write_string(info->dbgfs_params.channel,
> - sizeof(info->dbgfs_params.channel),
> - ppos, buf, size);
> -}
> -
> -static const struct file_operations dtf_channel_fops = {
> - .read = dtf_read_channel,
> - .write = dtf_write_channel,
> - .open = simple_open,
> - .llseek = default_llseek,
> -};
> -
> -static ssize_t dtf_read_device(struct file *file, char __user *buf,
> - size_t count, loff_t *ppos)
> -{
> - struct dmatest_info *info = file->private_data;
> - return simple_read_from_buffer(buf, count, ppos,
> - info->dbgfs_params.device,
> - strlen(info->dbgfs_params.device));
> -}
> -
> -static ssize_t dtf_write_device(struct file *file, const char __user *buf,
> - size_t size, loff_t *ppos)
> -{
> - struct dmatest_info *info = file->private_data;
> - return dtf_write_string(info->dbgfs_params.device,
> - sizeof(info->dbgfs_params.device),
> - ppos, buf, size);
> -}
> -
> -static const struct file_operations dtf_device_fops = {
> - .read = dtf_read_device,
> - .write = dtf_write_device,
> - .open = simple_open,
> - .llseek = default_llseek,
> -};
> -
> static ssize_t dtf_read_run(struct file *file, char __user *user_buf,
> size_t count, loff_t *ppos)
> {
> @@ -1187,7 +1131,6 @@ static const struct file_operations dtf_results_fops = {
> static int dmatest_register_dbgfs(struct dmatest_info *info)
> {
> struct dentry *d;
> - struct dmatest_params *params = &info->dbgfs_params;
> int ret = -ENOMEM;
>
> d = debugfs_create_dir("dmatest", NULL);
> @@ -1198,56 +1141,6 @@ static int dmatest_register_dbgfs(struct dmatest_info *info)
>
> info->root = d;
>
> - /* Copy initial values */
> - memcpy(params, &info->params, sizeof(*params));
> -
> - /* Test parameters */
> -
> - d = debugfs_create_u32("test_buf_size", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->buf_size);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_file("channel", S_IRUGO | S_IWUSR, info->root,
> - info, &dtf_channel_fops);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_file("device", S_IRUGO | S_IWUSR, info->root,
> - info, &dtf_device_fops);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("threads_per_chan", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->threads_per_chan);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("max_channels", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->max_channels);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("iterations", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->iterations);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("xor_sources", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->xor_sources);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("pq_sources", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->pq_sources);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> - d = debugfs_create_u32("timeout", S_IWUSR | S_IRUGO, info->root,
> - (u32 *)&params->timeout);
> - if (IS_ERR_OR_NULL(d))
> - goto err_node;
> -
> /* Run or stop threaded test */
> d = debugfs_create_file("run", S_IWUSR | S_IRUGO, info->root,
> info, &dtf_run_fops);
> @@ -1272,7 +1165,6 @@ err_root:
> static int __init dmatest_init(void)
> {
> struct dmatest_info *info = &test_info;
> - struct dmatest_params *params = &info->params;
> int ret;
>
> memset(info, 0, sizeof(*info));
> @@ -1283,17 +1175,6 @@ static int __init dmatest_init(void)
> mutex_init(&info->results_lock);
> INIT_LIST_HEAD(&info->results);
>
> - /* Set default parameters */
> - params->buf_size = test_buf_size;
> - strlcpy(params->channel, test_channel, sizeof(params->channel));
> - strlcpy(params->device, test_device, sizeof(params->device));
> - params->threads_per_chan = threads_per_chan;
> - params->max_channels = max_channels;
> - params->iterations = iterations;
> - params->xor_sources = xor_sources;
> - params->pq_sources = pq_sources;
> - params->timeout = timeout;
> -
> ret = dmatest_register_dbgfs(info);
> if (ret)
> return ret;

--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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