[patch 2/2] ACPI / debugger: copy_to_user doesn't return errors

Dan Carpenter
2015-12-24T07:25:00Z

The copy_to/from_user() functions don't return error codes, they return
the number of bytes remaining. We had intended to return -EFUALT here.
We actually have already checked access_ok() in an earlier function so
I don't think these functions will fail but let's fix it anyway.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c
index f2c92ab..2a1777b 100644
--- a/drivers/acpi/acpi_dbg.c
+++ b/drivers/acpi/acpi_dbg.c
@@ -592,9 +592,10 @@ static int acpi_aml_read_user(char __user *buf, int len)
smp_rmb();
p = &crc->buf[crc->tail];
n = min(len, circ_count_to_end(crc));
- ret = copy_to_user(buf, p, n);
- if (IS_ERR_VALUE(ret))
+ if (copy_to_user(buf, p, n)) {
+ ret = -EFAULT;
goto out;
+ }
/* sync tail after removing logs */
smp_mb();
crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1);
@@ -661,9 +662,10 @@ static int acpi_aml_write_user(const char __user *buf, int len)
smp_mb();
p = &crc->buf[crc->head];
n = min(len, circ_space_to_end(crc));
- ret = copy_from_user(p, buf, n);
- if (IS_ERR_VALUE(ret))
+ if (copy_from_user(p, buf, n)) {
+ ret = -EFAULT;
goto out;
+ }
/* sync head after inserting cmds */
smp_wmb();
crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1);