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path: root/drivers/char/mem.c
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Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 31cae88a730b..687d4af6945d 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -171,7 +171,7 @@ static ssize_t read_mem(struct file *file, char __user *buf,
if (!ptr)
goto failed;
- probe = probe_kernel_read(bounce, ptr, sz);
+ probe = copy_from_kernel_nofault(bounce, ptr, sz);
unxlate_dev_mem_ptr(p, ptr);
if (probe)
goto failed;
@@ -814,7 +814,8 @@ static struct inode *devmem_inode;
#ifdef CONFIG_IO_STRICT_DEVMEM
void revoke_devmem(struct resource *res)
{
- struct inode *inode = READ_ONCE(devmem_inode);
+ /* pairs with smp_store_release() in devmem_init_inode() */
+ struct inode *inode = smp_load_acquire(&devmem_inode);
/*
* Check that the initialization has completed. Losing the race
@@ -1028,8 +1029,11 @@ static int devmem_init_inode(void)
return rc;
}
- /* publish /dev/mem initialized */
- WRITE_ONCE(devmem_inode, inode);
+ /*
+ * Publish /dev/mem initialized.
+ * Pairs with smp_load_acquire() in revoke_devmem().
+ */
+ smp_store_release(&devmem_inode, inode);
return 0;
}