diff options
| author | Paul Mundt <lethal@linux-sh.org> | 2010-02-04 09:58:28 +0300 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2010-02-05 05:53:28 +0300 |
| commit | 2c940db250c1610d95ea5331dc819b8bd4db96ae (patch) | |
| tree | fc1e5338940c4562d6b0e9df9e1a5525407b95c3 /drivers | |
| parent | 2717568e7c44fe7dc3f4f52ea823811cfeede2b5 (diff) | |
| download | linux-2c940db250c1610d95ea5331dc819b8bd4db96ae.tar.xz | |
usb: r8a66597-hcd: Fix up spinlock recursion in root hub polling.
The current root hub polling code exhibits a spinlock recursion on the
private controller lock. r8a66597_root_hub_control() is called from
r8a66597_timer() which grabs the lock and disables IRQs. The following
chain emerges:
r8a66597_timer() <-- lock taken
r8a66597_root_hub_control()
r8a66597_check_syssts()
usb_hcd_poll_rh_status() <-- acquires the same lock
/* insert death here */
The entire chain requires IRQs to be disabled, so we just unlock and
relock around the call to usb_hcd_poll_rh_status() while leaving the
IRQ state unchanged.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/host/r8a66597-hcd.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/host/r8a66597-hcd.c b/drivers/usb/host/r8a66597-hcd.c index 50a3e2d6a6cc..bee558aed427 100644 --- a/drivers/usb/host/r8a66597-hcd.c +++ b/drivers/usb/host/r8a66597-hcd.c @@ -1022,6 +1022,8 @@ static void start_root_hub_sampling(struct r8a66597 *r8a66597, int port, /* this function must be called with interrupt disabled */ static void r8a66597_check_syssts(struct r8a66597 *r8a66597, int port, u16 syssts) +__releases(r8a66597->lock) +__acquires(r8a66597->lock) { if (syssts == SE0) { r8a66597_write(r8a66597, ~ATTCH, get_intsts_reg(port)); @@ -1039,7 +1041,9 @@ static void r8a66597_check_syssts(struct r8a66597 *r8a66597, int port, usb_hcd_resume_root_hub(r8a66597_to_hcd(r8a66597)); } + spin_unlock(&r8a66597->lock); usb_hcd_poll_rh_status(r8a66597_to_hcd(r8a66597)); + spin_lock(&r8a66597->lock); } /* this function must be called with interrupt disabled */ |