From fc5966589b9e2e38f6a2e53aa712ca2978baa32c Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Wed, 30 Sep 2020 13:27:51 -0700 Subject: [PATCH] Fix buggy procfs_list_seq_next warning The kernel seq_read() helper function expects ->next() to update the passed position even there are no more entries. Failure to do so results in the following warning being logged. seq_file: buggy .next function procfs_list_seq_next [spl] did not update position index Functionally there is no issue with the way procfs_list_seq_next() is implemented and the warning is harmless. However, we want to silence this some what scary incorrect warning. This commit updates the Linux procfs code to advance the position even for the last entry. Reviewed-by: Tony Hutter Signed-off-by: Brian Behlendorf Closes #10984 Closes #10996 --- module/os/linux/spl/spl-procfs-list.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/module/os/linux/spl/spl-procfs-list.c b/module/os/linux/spl/spl-procfs-list.c index 778da7bc4..cae13228c 100644 --- a/module/os/linux/spl/spl-procfs-list.c +++ b/module/os/linux/spl/spl-procfs-list.c @@ -89,7 +89,17 @@ procfs_list_next_node(procfs_list_cursor_t *cursor, loff_t *pos) cursor->cached_node = next_node; cursor->cached_pos = NODE_ID(procfs_list, cursor->cached_node); *pos = cursor->cached_pos; + } else { + /* + * seq_read() expects ->next() to update the position even + * when there are no more entries. Advance the position to + * prevent a warning from being logged. + */ + cursor->cached_node = NULL; + cursor->cached_pos++; + *pos = cursor->cached_pos; } + return (next_node); } @@ -105,6 +115,8 @@ procfs_list_seq_start(struct seq_file *f, loff_t *pos) cursor->cached_node = SEQ_START_TOKEN; cursor->cached_pos = 0; return (SEQ_START_TOKEN); + } else if (cursor->cached_node == NULL) { + return (NULL); } /*