Commit 8ff410da authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

sysdev: fix prototype for memory_sysdev_class show/store functions 



The function prototype mismatches in call stack:

                [<ffffffff81494268>] print_block_size+0x58/0x60
                [<ffffffff81487e3f>] sysdev_class_show+0x1f/0x30
                [<ffffffff811d629b>] sysfs_read_file+0xcb/0x1f0
                [<ffffffff81176328>] vfs_read+0xc8/0x180

Due to prototype mismatch, print_block_size() will sprintf() into
*attribute instead of *buf, hence user space will read the initial
zeros from *buf:
	$ hexdump /sys/devices/system/memory/block_size_bytes
	0000000 0000 0000 0000 0000
	0000008

After patch:
	cat /sys/devices/system/memory/block_size_bytes
	0x8000000

This complements commits c29af9636 and 4a0b2b4d.

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: "Zheng, Shaohui" <shaohui.zheng@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ba168fc3

drivers/base/memory.c

+20 −12
Original line number Diff line number Diff line
@@ -309,17 +309,19 @@ static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL); 
 * Block size attribute stuff

 */

static ssize_t

print_block_size(struct class *class, char *buf)

print_block_size(struct sysdev_class *class,

		 struct sysdev_class_attribute *class_attr,

		 char *buf)

{

	return sprintf(buf, "%#lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);

}



static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);

static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);



static int block_size_init(void)

{

	return sysfs_create_file(&memory_sysdev_class.kset.kobj,

				&class_attr_block_size_bytes.attr);

				&attr_block_size_bytes.attr);

}



/*
@@ -330,7 +332,9 @@ static int block_size_init(void) 
 */

#ifdef CONFIG_ARCH_MEMORY_PROBE

static ssize_t

memory_probe_store(struct class *class, const char *buf, size_t count)

memory_probe_store(struct sysdev_class *class,

		   struct sysdev_class_attribute *class_attr,

		   const char *buf, size_t count)

{

	u64 phys_addr;

	int nid;
@@ -346,12 +350,12 @@ memory_probe_store(struct class *class, const char *buf, size_t count) 


	return count;

}

static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);

static SYSDEV_CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);



static int memory_probe_init(void)

{

	return sysfs_create_file(&memory_sysdev_class.kset.kobj,

				&class_attr_probe.attr);

				&attr_probe.attr);

}

#else

static inline int memory_probe_init(void)
@@ -367,7 +371,9 @@ static inline int memory_probe_init(void) 


/* Soft offline a page */

static ssize_t

store_soft_offline_page(struct class *class, const char *buf, size_t count)

store_soft_offline_page(struct sysdev_class *class,

			struct sysdev_class_attribute *class_attr,

			const char *buf, size_t count)

{

	int ret;

	u64 pfn;
@@ -384,7 +390,9 @@ store_soft_offline_page(struct class *class, const char *buf, size_t count) 


/* Forcibly offline a page, including killing processes. */

static ssize_t

store_hard_offline_page(struct class *class, const char *buf, size_t count)

store_hard_offline_page(struct sysdev_class *class,

			struct sysdev_class_attribute *class_attr,

			const char *buf, size_t count)

{

	int ret;

	u64 pfn;
@@ -397,18 +405,18 @@ store_hard_offline_page(struct class *class, const char *buf, size_t count) 
	return ret ? ret : count;

}



static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);

static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);

static SYSDEV_CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);

static SYSDEV_CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);



static __init int memory_fail_init(void)

{

	int err;



	err = sysfs_create_file(&memory_sysdev_class.kset.kobj,

				&class_attr_soft_offline_page.attr);

				&attr_soft_offline_page.attr);

	if (!err)

		err = sysfs_create_file(&memory_sysdev_class.kset.kobj,

				&class_attr_hard_offline_page.attr);

				&attr_hard_offline_page.attr);

	return err;

}

#else

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