From 4781ace0ddff8057f2c1bf1811ae4886f8b88876 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Sat, 3 Dec 2011 23:41:31 +0100 Subject: usb: fix number of mapped SG DMA entries commit bc677d5b64644c399cd3db6a905453e611f402ab upstream. 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: [] warn_slowpath_common+0x80/0x98 [] warn_slowpath_fmt+0x41/0x43 [] check_unmap+0x4e4/0x695 [] ? trace_hardirqs_off+0xd/0xf [] ? _raw_spin_unlock_irqrestore+0x33/0x50 [] debug_dma_unmap_sg+0xeb/0x117 [] usb_hcd_unmap_urb_for_dma+0x71/0x188 [] unmap_urb_for_dma+0x20/0x22 [] usb_hcd_giveback_urb+0x5d/0xc0 [] ehci_urb_done+0xf7/0x10c [ehci_hcd] [] qh_completions+0x429/0x4bd [ehci_hcd] [] ehci_work+0x95/0x9c0 [ehci_hcd] ... ---[ end trace f29ac88a5a48c580 ]--- Mapped at: [] debug_dma_map_sg+0x45/0x139 [] usb_hcd_map_urb_for_dma+0x22e/0x478 [] usb_hcd_submit_urb+0x63f/0x6fa [] usb_submit_urb+0x2c7/0x2de [] usb_sg_wait+0x55/0x161 Signed-off-by: Clemens Ladisch Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-q.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/usb/host/ehci-q.c') diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 4e4066c35a09..fef1db3da37f 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -647,7 +647,7 @@ qh_urb_transaction ( /* * data transfer stage: buffer setup */ - i = urb->num_sgs; + i = urb->num_mapped_sgs; if (len > 0 && i > 0) { sg = urb->sg; buf = sg_dma_address(sg); -- cgit v1.2.3