diff options
| author | Clemens Ladisch <clemens@ladisch.de> | 2011-12-03 23:41:31 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-12-09 16:18:19 -0800 |
| commit | bc677d5b64644c399cd3db6a905453e611f402ab (patch) | |
| tree | d973a02c33f0e0d407e9ec7c6054220e15d5c72f /drivers/usb/core | |
| parent | 8ad028bd973ec1ead4982e21ab0400c956aff4b5 (diff) | |
| download | linux-bc677d5b64644c399cd3db6a905453e611f402ab.tar.gz | |
usb: fix number of mapped SG DMA entries
Add a new field num_mapped_sgs to struct urb so that we have a place to
store the number of mapped entries and can also retain the original
value of entries in num_sgs. Previously, usb_hcd_map_urb_for_dma()
would overwrite this with the number of mapped entries, which would
break dma_unmap_sg() because it requires the original number of entries.
This fixes warnings like the following when using USB storage devices:
------------[ cut here ]------------
WARNING: at lib/dma-debug.c:902 check_unmap+0x4e4/0x695()
ehci_hcd 0000:00:12.2: DMA-API: device driver frees DMA sg list with different entry count [map count=4] [unmap count=1]
Modules linked in: ohci_hcd ehci_hcd
Pid: 0, comm: kworker/0:1 Not tainted 3.2.0-rc2+ #319
Call Trace:
<IRQ> [<ffffffff81036d3b>] warn_slowpath_common+0x80/0x98
[<ffffffff81036de7>] warn_slowpath_fmt+0x41/0x43
[<ffffffff811fa5ae>] check_unmap+0x4e4/0x695
[<ffffffff8105e92c>] ? trace_hardirqs_off+0xd/0xf
[<ffffffff8147208b>] ? _raw_spin_unlock_irqrestore+0x33/0x50
[<ffffffff811fa84a>] debug_dma_unmap_sg+0xeb/0x117
[<ffffffff8137b02f>] usb_hcd_unmap_urb_for_dma+0x71/0x188
[<ffffffff8137b166>] unmap_urb_for_dma+0x20/0x22
[<ffffffff8137b1c5>] usb_hcd_giveback_urb+0x5d/0xc0
[<ffffffffa0000d02>] ehci_urb_done+0xf7/0x10c [ehci_hcd]
[<ffffffffa0001140>] qh_completions+0x429/0x4bd [ehci_hcd]
[<ffffffffa000340a>] ehci_work+0x95/0x9c0 [ehci_hcd]
...
---[ end trace f29ac88a5a48c580 ]---
Mapped at:
[<ffffffff811faac4>] debug_dma_map_sg+0x45/0x139
[<ffffffff8137bc0b>] usb_hcd_map_urb_for_dma+0x22e/0x478
[<ffffffff8137c494>] usb_hcd_submit_urb+0x63f/0x6fa
[<ffffffff8137d01c>] usb_submit_urb+0x2c7/0x2de
[<ffffffff8137dcd4>] usb_sg_wait+0x55/0x161
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core')
| -rw-r--r-- | drivers/usb/core/hcd.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 43a89e4ba928..2cec49d1773d 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1398,11 +1398,10 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, ret = -EAGAIN; else urb->transfer_flags |= URB_DMA_MAP_SG; - if (n != urb->num_sgs) { - urb->num_sgs = n; + urb->num_mapped_sgs = n; + if (n != urb->num_sgs) urb->transfer_flags |= URB_DMA_SG_COMBINED; - } } else if (urb->sg) { struct scatterlist *sg = urb->sg; urb->transfer_dma = dma_map_page( |