[PATCH 26/29] drivers, usb: convert dev_data.count from atomic_t to refcount_t
From: Elena Reshetova <elena.reshetova@intel.com>
Date: 2017-03-06 14:25:43
Also in:
linux-bcache, linux-media, linux-pci, linux-raid, linux-s390, linux-scsi, linux-serial, lkml, xen-devel
Subsystem:
the rest, usb subsystem · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <redacted> Signed-off-by: Kees Cook <redacted> Signed-off-by: David Windsor <redacted> --- drivers/usb/gadget/legacy/inode.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 79a2d8f..81d76f3 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c@@ -27,6 +27,7 @@ #include <linux/mmu_context.h> #include <linux/aio.h> #include <linux/uio.h> +#include <linux/refcount.h> #include <linux/device.h> #include <linux/moduleparam.h>
@@ -114,7 +115,7 @@ enum ep0_state { struct dev_data { spinlock_t lock; - atomic_t count; + refcount_t count; enum ep0_state state; /* P: lock */ struct usb_gadgetfs_event event [N_EVENT]; unsigned ev_next;
@@ -150,12 +151,12 @@ struct dev_data { static inline void get_dev (struct dev_data *data) { - atomic_inc (&data->count); + refcount_inc (&data->count); } static void put_dev (struct dev_data *data) { - if (likely (!atomic_dec_and_test (&data->count))) + if (likely (!refcount_dec_and_test (&data->count))) return; /* needs no more cleanup */ BUG_ON (waitqueue_active (&data->wait));
@@ -170,7 +171,7 @@ static struct dev_data *dev_new (void) if (!dev) return NULL; dev->state = STATE_DEV_DISABLED; - atomic_set (&dev->count, 1); + refcount_set (&dev->count, 1); spin_lock_init (&dev->lock); INIT_LIST_HEAD (&dev->epfiles); init_waitqueue_head (&dev->wait);
--
2.7.4
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