[PATCH 3/5] sysfs: fix problems with binary files

[Greg Kroah-Hartman]

Some sysfs binary files don't like having 0 passed to them as a size.
Fix this up at the root by just returning to the vfs if userspace asks
us for a zero sized buffer.

Thanks to Pavel Roskin for pointing this out.

Reported-by: Pavel Roskin <proski@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 fs/sysfs/bin.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index 66f6e58..f2c478c 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -63,6 +63,9 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
 	int count = min_t(size_t, bytes, PAGE_SIZE);
 	char *temp;
 
+	if (!bytes)
+		return 0;
+
 	if (size) {
 		if (offs > size)
 			return 0;
@@ -131,6 +134,9 @@ static ssize_t write(struct file *file, const char __user *userbuf,
 	int count = min_t(size_t, bytes, PAGE_SIZE);
 	char *temp;
 
+	if (!bytes)
+		return 0;
+
 	if (size) {
 		if (offs > size)
 			return 0;
-- 
1.6.0.4

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