Re: [PATCH 1/4] mm: cma: add currently allocated CMA buffers list to debugfs

From: Stefan Strogin
Date: Wed Feb 18 2015 - 05:06:46 EST


Hello

On 13/02/15 06:16, Joonsoo Kim wrote:
> On Fri, Feb 13, 2015 at 01:15:41AM +0300, Stefan Strogin wrote:
>> static int cma_debugfs_get(void *data, u64 *val)
>> {
>> unsigned long *p = data;
>> @@ -125,6 +221,52 @@ static int cma_alloc_write(void *data, u64 val)
>>
>> DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
>>
>> +static int cma_buffers_read(struct file *file, char __user *userbuf,
>> + size_t count, loff_t *ppos)
>> +{
>> + struct cma *cma = file->private_data;
>> + struct cma_buffer *cmabuf;
>> + struct stack_trace trace;
>> + char *buf;
>> + int ret, n = 0;
>> +
>> + if (*ppos < 0 || !count)
>> + return -EINVAL;
>> +
>> + buf = kmalloc(count, GFP_KERNEL);
>> + if (!buf)
>> + return -ENOMEM;
>
> Is count limited within proper size boundary for kmalloc()?
> If it can exceed page size, using vmalloc() is better than this.
>
> Thanks.
>

You are right. On my systems it is always much bigger than page size.
Thanks.
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