usb: fix number of mapped SG DMA entries (bc677d5b) · Commits · 戴 / test

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>

drivers/usb/core/hcd.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -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(

drivers/usb/host/ehci-q.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -658,7 +658,7 @@ 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);

drivers/usb/host/uhci-q.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -943,7 +943,7 @@ static int uhci_submit_common(struct uhci_hcd uhci, struct urb urb,
		if (usb_pipein(urb->pipe))
		status \|= TD_CTRL_SPD;

		i = urb->num_sgs;
		i = urb->num_mapped_sgs;
		if (len > 0 && i > 0) {
		sg = urb->sg;
		data = sg_dma_address(sg);

drivers/usb/host/whci/qset.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -443,7 +443,7 @@ static int qset_add_urb_sg(struct whc whc, struct whc_qset qset, struct urb *u

		remaining = urb->transfer_buffer_length;

		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
		for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
		dma_addr_t dma_addr;
		size_t dma_remaining;
		dma_addr_t sp, ep;
		@@ -561,7 +561,7 @@ static int qset_add_urb_sg_linearize(struct whc whc, struct whc_qset qset,

		remaining = urb->transfer_buffer_length;

		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
		for_each_sg(urb->sg, sg, urb->num_mapped_sgs, i) {
		size_t len;
		size_t sg_remaining;
		void *orig;

drivers/usb/host/xhci-ring.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -2551,7 +2551,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd xhci, struct urb urb)
		struct scatterlist *sg;

		sg = NULL;
		num_sgs = urb->num_sgs;
		num_sgs = urb->num_mapped_sgs;
		temp = urb->transfer_buffer_length;

		xhci_dbg(xhci, "count sg list trbs: \n");
		@@ -2735,7 +2735,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
		return -EINVAL;

		num_trbs = count_sg_trbs_needed(xhci, urb);
		num_sgs = urb->num_sgs;
		num_sgs = urb->num_mapped_sgs;
		total_packet_count = roundup(urb->transfer_buffer_length,
		usb_endpoint_maxp(&urb->ep->desc));

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