block: fix partial read() of /proc/{partitions,diskstats}
The proc files get truncated if they do not fit into the buffer with
a single read(). We need to move the seq_file index from the callback
of class_find_device() to the caller of class_find_device(), to keep
its value across multiple invocations of the callback.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/block/genhd.c b/block/genhd.c
index c13cc77..f34befc 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -293,25 +293,26 @@
/* iterator */
static int find_start(struct device *dev, void *data)
{
- loff_t k = *(loff_t *)data;
+ loff_t *k = data;
if (dev->type != &disk_type)
return 0;
- if (!k--)
+ if (!*k)
return 1;
+ (*k)--;
return 0;
}
static void *part_start(struct seq_file *part, loff_t *pos)
{
struct device *dev;
- loff_t n = *pos;
+ loff_t k = *pos;
- if (!n)
+ if (!k)
seq_puts(part, "major minor #blocks name\n\n");
mutex_lock(&block_class_lock);
- dev = class_find_device(&block_class, NULL, (void *)pos, find_start);
+ dev = class_find_device(&block_class, NULL, &k, find_start);
if (dev)
return dev_to_disk(dev);
return NULL;
@@ -568,9 +569,10 @@
static void *diskstats_start(struct seq_file *part, loff_t *pos)
{
struct device *dev;
+ loff_t k = *pos;
mutex_lock(&block_class_lock);
- dev = class_find_device(&block_class, NULL, (void *)pos, find_start);
+ dev = class_find_device(&block_class, NULL, &k, find_start);
if (dev)
return dev_to_disk(dev);
return NULL;