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block: fix partial read() of /proc/{partitions,diskstats}

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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>
This commit is contained in:
Kay Sievers 2008-08-16 14:30:30 +02:00 committed by Greg Kroah-Hartman
parent f5a6d958b5
commit 068281d302
1 changed files with 8 additions and 6 deletions
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14
block/genhd.c
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@ -293,25 +293,26 @@ void __init printk_all_partitions(void)
/* iterator */ /* iterator */
static int find_start(struct device *dev, void *data) static int find_start(struct device *dev, void *data)
{ {
loff_t k = *(loff_t *)data; loff_t *k = data;
if (dev->type != &disk_type) if (dev->type != &disk_type)
return 0; return 0;
if (!k--) if (!*k)
return 1; return 1;
(*k)--;
return 0; return 0;
} }
static void *part_start(struct seq_file *part, loff_t *pos) static void *part_start(struct seq_file *part, loff_t *pos)
{ {
struct device *dev; struct device *dev;
loff_t n = *pos; loff_t k = *pos;
if (!n) if (!k)
seq_puts(part, "major minor #blocks name\n\n"); seq_puts(part, "major minor #blocks name\n\n");
mutex_lock(&block_class_lock); 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) if (dev)
return dev_to_disk(dev); return dev_to_disk(dev);
return NULL; return NULL;
@ -568,9 +569,10 @@ static struct device_type disk_type = {
static void *diskstats_start(struct seq_file *part, loff_t *pos) static void *diskstats_start(struct seq_file *part, loff_t *pos)
{ {
struct device *dev; struct device *dev;
loff_t k = *pos;
mutex_lock(&block_class_lock); 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) if (dev)
return dev_to_disk(dev); return dev_to_disk(dev);
return NULL; return NULL;