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| author | Johan Hovold <jhovold@gmail.com> | 2013-07-26 11:55:17 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-09-10 01:57:14 +0100 |
| commit | 6380025aff7900370d4488ee4bfd95ac6c6491d5 (patch) | |
| tree | 4bfb29a1026cf2314c9b43356bc0bb1a03539b0b /drivers/usb/serial/mos7840.c | |
| parent | 6d047ebfeb1e96641e65cb9bf7de132fc565c01e (diff) | |
| download | kernel_samsung_smdk4412-6380025aff7900370d4488ee4bfd95ac6c6491d5.zip kernel_samsung_smdk4412-6380025aff7900370d4488ee4bfd95ac6c6491d5.tar.gz kernel_samsung_smdk4412-6380025aff7900370d4488ee4bfd95ac6c6491d5.tar.bz2 | |
USB: mos7840: fix race in register handling
commit d8a083cc746664916d9d36ed9e4d08a29525f245 upstream.
Fix race in mos7840_get_reg which unconditionally manipulated the
control urb (which may already be in use) by adding a control-urb busy
flag.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/usb/serial/mos7840.c')
| -rw-r--r-- | drivers/usb/serial/mos7840.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c index 5e8c736..5d2501e 100644 --- a/drivers/usb/serial/mos7840.c +++ b/drivers/usb/serial/mos7840.c @@ -185,6 +185,10 @@ #define URB_TRANSFER_BUFFER_SIZE 32 /* URB Size */ +enum mos7840_flag { + MOS7840_FLAG_CTRL_BUSY, +}; + static const struct usb_device_id moschip_port_id_table[] = { {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)}, {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)}, @@ -258,6 +262,8 @@ struct moschip_port { struct urb *write_urb_pool[NUM_URBS]; char busy[NUM_URBS]; bool read_urb_busy; + + unsigned long flags; }; @@ -519,11 +525,11 @@ static void mos7840_control_callback(struct urb *urb) /* this urb is terminated, clean up */ dbg("%s - urb shutting down with status: %d", __func__, status); - return; + goto out; default: dbg("%s - nonzero urb status received: %d", __func__, status); - return; + goto out; } dbg("%s urb buffer size is %d", __func__, urb->actual_length); @@ -536,6 +542,8 @@ static void mos7840_control_callback(struct urb *urb) mos7840_handle_new_msr(mos7840_port, regval); else if (mos7840_port->MsrLsr == 1) mos7840_handle_new_lsr(mos7840_port, regval); +out: + clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mos7840_port->flags); } static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, @@ -546,6 +554,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, unsigned char *buffer = mcs->ctrl_buf; int ret; + if (test_and_set_bit_lock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags)) + return -EBUSY; + dr->bRequestType = MCS_RD_RTYPE; dr->bRequest = MCS_RDREQ; dr->wValue = cpu_to_le16(Wval); /* 0 */ @@ -557,6 +568,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg, mos7840_control_callback, mcs); mcs->control_urb->transfer_buffer_length = 2; ret = usb_submit_urb(mcs->control_urb, GFP_ATOMIC); + if (ret) + clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags); + return ret; } |