From 7abfabaf5f805f5171d133ce6af9b65ab766e76a Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Wed, 17 Mar 2021 15:04:39 +0100 Subject: [PATCH] md: Fix missing unused status line of /proc/mdstat Reading /proc/mdstat with a read buffer size that would not fit the unused status line in the first read will skip this line from the output. So 'dd if=/proc/mdstat bs=64 2>/dev/null' will not print something like: unused devices: Don't return NULL immediately in start() for v=2 but call show() once to print the status line also for multiple reads. Cc: stable@vger.kernel.org Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Signed-off-by: Jan Glauber Signed-off-by: Song Liu --- drivers/md/md.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 498a1c2..368cad6 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8153,7 +8153,11 @@ static void *md_seq_start(struct seq_file *seq, loff_t *pos) loff_t l = *pos; struct mddev *mddev; - if (l >= 0x10000) + if (l == 0x10000) { + ++*pos; + return (void *)2; + } + if (l > 0x10000) return NULL; if (!l--) /* header */ -- 2.7.4