On 17.09.22 09:14, Akinobu Mita wrote:
The simple attribute files do not accept a negative value since the
commit 488dac0c9237 ("libfs: fix error cast of negative value in
simple_attr_write()"), so we can no longer use DEFINE_SIMPLE_ATTRIBUTE() to
define a file operations for errno value.
Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()")
Reported-by: Zhao Gongyi <zhaogongyi@xxxxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
But shouldn't we fix simple_attr_write() instead?I mean, simple_attr_read() might use attr->fmt to print a signed value, but simple_attr_write() fails on signed values now?
I might be wrong, but there is a disconnect. I feel like simple_attr_write() should similarly make decisions based on attr->fmt.
--- v2: Fix Reported-by line lib/notifier-error-inject.c | 38 ++++++++++++++++++++++++++++++------- 1 file changed, 31 insertions(+), 7 deletions(-) diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c index 21016b32d313..30ec41f58d53 100644 --- a/lib/notifier-error-inject.c +++ b/lib/notifier-error-inject.c @@ -3,20 +3,44 @@#include "notifier-error-inject.h" -static int debugfs_errno_set(void *data, u64 val)+static int notifier_err_errno_show(struct seq_file *m, void *data) { - *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); + int *value = m->private; + + seq_printf(m, "%d\n", *value); + return 0; }-static int debugfs_errno_get(void *data, u64 *val)+static int notifier_err_errno_open(struct inode *inode, struct file *file) { - *val = *(int *)data; - return 0; + return single_open(file, notifier_err_errno_show, inode->i_private); +} + +static ssize_t notifier_err_errno_write(struct file *file, const char __user *ubuf, size_t len, + loff_t *offp) +{ + struct seq_file *m = file->private_data; + int *value = m->private; + int ret; + + ret = kstrtoint_from_user(ubuf, len, 0, value); + if (ret) + return ret; + + *value = clamp(*value, -MAX_ERRNO, 0); + + return len; }-DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,- "%lld\n"); +static const struct file_operations fops_errno = { + .owner = THIS_MODULE, + .open = notifier_err_errno_open, + .read = seq_read, + .write = notifier_err_errno_write, + .llseek = seq_lseek, + .release = single_release, +};static struct dentry *debugfs_create_errno(const char *name, umode_t mode,struct dentry *parent, int *value)
-- Thanks, David / dhildenb
