[PATCH] misc: tifm: Remove the adapter ID after device_del()

[PATCH] misc: tifm: Remove the adapter ID after device_del()

[Changyul Lee]

tifm_remove_adapter() removes the adapter ID from tifm_adapter_idr
before device_del() removes the "tifm<N>" device. An adapter added in
between, for example by another TI FlashMedia controller being probed,
can get the same ID, and its device_add() fails:

  sysfs: cannot create duplicate filename '/class/tifm_adapter/tifm0'

Remove the ID after device_del(), as the error path of
tifm_add_adapter() already does.

Fixes: 6113ed73e61a ("tifm: move common adapter management tasks from tifm_7xx1 to tifm_core")
Signed-off-by: Changyul Lee <lcy8047@gmail.com>
---
Found with a static analysis tool we are developing.

Reproduced in QEMU (x86_64) with a test module that runs two kthreads
for 20 seconds. Each kthread allocates, adds, removes and frees an
adapter in a loop, under its own platform device as the parent.
Without this patch, tifm_add_adapter() failed with -EEXIST 125066 to
126356 times per run in three runs. With it, it never failed in three
runs.
Not tested on TI FlashMedia hardware.

 drivers/misc/tifm_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/tifm_core.c b/drivers/misc/tifm_core.c
index 03d1324bc253..91f9b377588d 100644
--- a/drivers/misc/tifm_core.c
+++ b/drivers/misc/tifm_core.c
@@ -223,10 +223,10 @@ void tifm_remove_adapter(struct tifm_adapter *fm)
 			device_unregister(&fm->sockets[cnt]->dev);
 	}
 
+	device_del(&fm->dev);
 	spin_lock(&tifm_adapter_lock);
 	idr_remove(&tifm_adapter_idr, fm->id);
 	spin_unlock(&tifm_adapter_lock);
-	device_del(&fm->dev);
 }
 EXPORT_SYMBOL(tifm_remove_adapter);
 

base-commit: 7475ea8b58616b33c04afb976cf0fbaad9dd63fb
-- 
2.43.0