Originally FFS_FL_CALL_CLOSED_CALLBACK flag has been used to
indicate if we should call ffs_closed_callback().
Commit 4b187fceec3c ("usb: gadget: FunctionFS: add devices
management code") changed its semantic to indicate if we should
call ffs_closed() function which does a little bit more.
This situation leads to:
[ 122.362269] ------------[ cut here ]------------
[ 122.362287] WARNING: CPU: 2 PID: 2384 at drivers/usb/gadget/function/f_fs.c:3417 ffs_ep0_write+0x730/0x810 [usb_f_fs]()
[ 122.362292] Modules linked in:
[ 122.362555] CPU: 2 PID: 2384 Comm: adbd Tainted: G W 4.1.0-0.rc4.git0.1.1.fc22.i686 #1
[ 122.362561] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/25/2014
[ 122.362567] c0d1f947 415badfa 00000000 d1029e64 c0a86e54 00000000 d1029e94 c045b937
[ 122.362584] c0c37f94 00000002 00000950 f9b313d4 00000d59 f9b2ebf0 f9b2ebf0 fffffff0
[ 122.362600] 00000003 deb53d00 d1029ea4 c045ba42 00000009 00000000 d1029f08 f9b2ebf0
[ 122.362617] Call Trace:
[ 122.362633] [<c0a86e54>] dump_stack+0x41/0x52
[ 122.362645] [<c045b937>] warn_slowpath_common+0x87/0xc0
[ 122.362658] [<f9b2ebf0>] ? ffs_ep0_write+0x730/0x810 [usb_f_fs]
[ 122.362668] [<f9b2ebf0>] ? ffs_ep0_write+0x730/0x810 [usb_f_fs]
[ 122.362678] [<c045ba42>] warn_slowpath_null+0x22/0x30
[ 122.362689] [<f9b2ebf0>] ffs_ep0_write+0x730/0x810 [usb_f_fs]
[ 122.362702] [<f9b2e4c0>] ? ffs_ep0_read+0x380/0x380 [usb_f_fs]
[ 122.362712] [<c05a1c1f>] __vfs_write+0x2f/0x100
[ 122.362722] [<c05a42f2>] ? __sb_start_write+0x52/0x110
[ 122.362731] [<c05a2534>] vfs_write+0x94/0x1b0
[ 122.362740] [<c0a8a1c0>] ? mutex_lock+0x10/0x30
[ 122.362749] [<c05a2f41>] SyS_write+0x51/0xb0
[ 122.362759] [<c0a8c71f>] sysenter_do_call+0x12/0x12
[ 122.362766] ---[ end trace 0673d3467cecf8db ]---
in some cases (reproduction path below). This commit get back
semantic of that flag and ensures that ffs_closed() is called
always when needed but ffs_closed_callback() is called only
if this flag is set.
Reproduction path:
Compile kernel without any UDC driver or bound some gadget
to existing one and then:
$ modprobe g_ffs
$ mount none -t functionfs mount_point
$ ffs-example mount_point
This will fail with -ENODEV as there is no udc.
$ ffs-example mount_point
This will fail with -EBUSY because ffs_data has not been
properly cleaned up.
Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 6bdb570..71f68c4 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -315,7 +315,6 @@ static ssize_t ffs_ep0_write(struct file *file, const char __user *buf,
return ret;
}
- set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
return len;
}
break;
@@ -1463,8 +1462,7 @@ static void ffs_data_clear(struct ffs_data *ffs)
{
ENTER();
- if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags))
- ffs_closed(ffs);
+ ffs_closed(ffs);
BUG_ON(ffs->gadget);
@@ -3422,9 +3420,13 @@ static int ffs_ready(struct ffs_data *ffs)
ffs_obj->desc_ready = true;
ffs_obj->ffs_data = ffs;
- if (ffs_obj->ffs_ready_callback)
+ if (ffs_obj->ffs_ready_callback) {
ret = ffs_obj->ffs_ready_callback(ffs);
+ if (ret)
+ goto done;
+ }
+ set_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags);
done:
ffs_dev_unlock();
return ret;
@@ -3443,7 +3445,8 @@ static void ffs_closed(struct ffs_data *ffs)
ffs_obj->desc_ready = false;
- if (ffs_obj->ffs_closed_callback)
+ if (test_and_clear_bit(FFS_FL_CALL_CLOSED_CALLBACK, &ffs->flags) &&
+ ffs_obj->ffs_closed_callback)
ffs_obj->ffs_closed_callback(ffs);
if (!ffs_obj->opts || ffs_obj->opts->no_configfs
--
1.7.9.5
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