From bc677d5b64644c399cd3db6a905453e611f402ab 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 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/usb.h b/include/linux/usb.h index 2f05a7f..4269c3f 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -1221,6 +1221,7 @@ struct urb { void *transfer_buffer; /* (in) associated data buffer */ dma_addr_t transfer_dma; /* (in) dma addr for transfer_buffer */ struct scatterlist *sg; /* (in) scatter gather buffer list */ + int num_mapped_sgs; /* (internal) mapped sg entries */ int num_sgs; /* (in) number of entries in the sg list */ u32 transfer_buffer_length; /* (in) data buffer length */ u32 actual_length; /* (return) actual transfer length */ -- cgit v1.1