xiaoxiang781216 commented on code in PR #11140:
URL: https://github.com/apache/nuttx/pull/11140#discussion_r1388243823
##########
fs/inode/fs_files.c:
##########
@@ -51,59 +51,118 @@
* Private Functions
****************************************************************************/
+/****************************************************************************
+ * Name: files_fget_index
+ ****************************************************************************/
+
+static FAR struct file *files_fget_index(FAR struct filelist *list,
+ int l1, int l2)
+{
+ FAR struct file *filep;
+ irqstate_t flags;
+
+ flags = enter_critical_section();
+
+ filep = &list->fl_files[l1][l2];
+
+ leave_critical_section(flags);
+
+ return filep;
+}
+
+/****************************************************************************
+ * Name: files_fget
+ ****************************************************************************/
+
+static FAR struct file *files_fget(FAR struct filelist *list, int fd)
+{
+ return files_fget_index(list, fd / CONFIG_NFILE_DESCRIPTORS_PER_BLOCK,
+ fd % CONFIG_NFILE_DESCRIPTORS_PER_BLOCK);
+}
+
/****************************************************************************
* Name: files_extend
****************************************************************************/
static int files_extend(FAR struct filelist *list, size_t row)
{
- FAR struct file **tmp;
+ FAR struct file **files;
+ uint8_t orig_rows;
+ FAR void *tmp;
+ int flags;
int i;
+ int j;
if (row <= list->fl_rows)
{
return 0;
}
- if (row * CONFIG_NFILE_DESCRIPTORS_PER_BLOCK > OPEN_MAX)
+ if (files_get_filecount(list) > OPEN_MAX)
{
return -EMFILE;
}
- tmp = kmm_realloc(list->fl_files, sizeof(FAR struct file *) * row);
- DEBUGASSERT(tmp);
- if (tmp == NULL)
+ orig_rows = list->fl_rows;
+
+ files = kmm_malloc(sizeof(FAR struct file *) * row);
+ DEBUGASSERT(files);
+ if (files == NULL)
{
return -ENFILE;
}
i = list->fl_rows;
do
{
- tmp[i] = kmm_zalloc(sizeof(struct file) *
- CONFIG_NFILE_DESCRIPTORS_PER_BLOCK);
- if (tmp[i] == NULL)
+ files[i] = kmm_zalloc(sizeof(struct file) *
+ CONFIG_NFILE_DESCRIPTORS_PER_BLOCK);
+ if (files[i] == NULL)
{
while (--i >= list->fl_rows)
{
- kmm_free(tmp[i]);
+ kmm_free(files[i]);
}
- kmm_free(tmp);
+ kmm_free(files);
return -ENFILE;
}
}
while (++i < row);
- list->fl_files = tmp;
- list->fl_rows = row;
+ flags = enter_critical_section();
- /* Note: If assertion occurs, the fl_rows has a overflow.
- * And there may be file descriptors leak in system.
+ /* To avoid race condition, if the file list is updated by other threads
+ * and list rows is greater or equal than temp list,
+ * release the obsolete buffers
*/
- DEBUGASSERT(list->fl_rows == row);
- return 0;
+ if (orig_rows != list->fl_rows && list->fl_rows >= row)
Review Comment:
```suggestion
if (orig_rows != list->fl_rows)
```
and change list->fl_rows >= row to DEBUGASSERT in if block.
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