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Commit 068281d3 authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

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: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent f5a6d958

block/genhd.c

+8 −6
Original line number Diff line number Diff line
@@ -293,25 +293,26 @@ void __init printk_all_partitions(void) 
/* 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 struct device_type disk_type = { 
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;