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UPSTREAM: xhci: Fix incorrect tracking of free space on transfer rings

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This incorrect tracking caused unnecessary ring expansion in some
usecases which over days of use consume a lot of memory.

xhci driver tries to keep track of free transfer blocks (TRBs) on the
ring buffer, but failed to add back some cancelled transfers that were
turned into no-op operations instead of just moving past them.

This can happen if there are several queued pending transfers which
then are cancelled in reverse order.

Solve this by counting the numer of steps we move the dequeue pointer
once we complete a transfer, and add it to the number of free trbs
instead of just adding the trb number of the current transfer.
This way we ensure we count the no-op trbs on the way as well.

Bug: 254441685
Fixes: 55f6153d8cc8 ("xhci: remove extra loop in interrupt context")
Cc: stable@vger.kernel.org
Reported-by: Miller Hunter <MillerH@hearthnhome.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217242
Tested-by: Miller Hunter <MillerH@hearthnhome.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230515134059.161110-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit fe82f16aafdaf8002281d3b9524291d4a4a28460)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Iba6c2cfad83029fcd567b5064f8ce80ccda0a701
This commit is contained in:
Mathias Nyman 2023-05-15 16:40:59 +03:00 committed by Lee Jones
parent bc78acae08
commit 6388400ba5
1 changed files with 28 additions and 1 deletions
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29
drivers/usb/host/xhci-ring.c
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@ -277,6 +277,26 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
trace_xhci_inc_enq(ring);
}
static int xhci_num_trbs_to(struct xhci_segment *start_seg, union xhci_trb *start,
struct xhci_segment *end_seg, union xhci_trb *end,
unsigned int num_segs)
{
union xhci_trb *last_on_seg;
int num = 0;
int i = 0;
do {
if (start_seg == end_seg && end >= start)
return num + (end - start);
last_on_seg = &start_seg->trbs[TRBS_PER_SEGMENT - 1];
num += last_on_seg - start;
start_seg = start_seg->next;
start = start_seg->trbs;
} while (i++ <= num_segs);
return -EINVAL;
}
/*
* Check to see if there's room to enqueue num_trbs on the ring and make sure
* enqueue pointer will not advance into dequeue segment. See rules above.
@ -2209,6 +2229,7 @@ static int finish_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
u32 trb_comp_code)
{
struct xhci_ep_ctx *ep_ctx;
int trbs_freed;
ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep->ep_index);
@ -2280,9 +2301,15 @@ static int finish_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
}
/* Update ring dequeue pointer */
trbs_freed = xhci_num_trbs_to(ep_ring->deq_seg, ep_ring->dequeue,
td->last_trb_seg, td->last_trb,
ep_ring->num_segs);
if (trbs_freed < 0)
xhci_dbg(xhci, "Failed to count freed trbs at TD finish\n");
else
ep_ring->num_trbs_free += trbs_freed;
ep_ring->dequeue = td->last_trb;
ep_ring->deq_seg = td->last_trb_seg;
ep_ring->num_trbs_free += td->num_trbs - 1;
inc_deq(xhci, ep_ring);
return xhci_td_cleanup(xhci, td, ep_ring, td->status);