#include <linux/module.h>
#include <linux/kobject.h>
+#include <linux/kallsyms.h>
+#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/list.h>
* The code works fine with PAGE_SIZE return but it's likely to
* indicate truncated result or overflow in normal use cases.
*/
- BUG_ON(count >= (ssize_t)PAGE_SIZE);
+ if (count >= (ssize_t)PAGE_SIZE) {
+ print_symbol("fill_read_buffer: %s returned bad count\n",
+ (unsigned long)ops->show);
+ /* Try to struggle along */
+ count = PAGE_SIZE - 1;
+ }
if (count >= 0) {
buffer->needs_read_fill = 0;
buffer->count = count;
ssize_t retval = 0;
mutex_lock(&buffer->mutex);
- if (buffer->needs_read_fill) {
+ if (buffer->needs_read_fill || *ppos == 0) {
retval = fill_read_buffer(file->f_path.dentry,buffer);
if (retval)
goto out;
* return POLLERR|POLLPRI, and select will return the fd whether
* it is waiting for read, write, or exceptions.
* Once poll/select indicates that the value has changed, you
- * need to close and re-open the file, as simply seeking and reading
- * again will not get new data, or reset the state of 'poll'.
+ * need to close and re-open the file, or seek to 0 and read again.
* Reminder: this only works for attributes which actively support
* it, and it is not possible to test an attribute from userspace
* to see if it supports poll (Neither 'poll' nor 'select' return