- Use a separate 'ret' variable for the result of prepare_transfer().
- No need to assign 'urb_priv' and 'td' until the last fragment.
- Add 'len_left' to count the bytes remaining, use instead of
'urb->transfer_buffer_length - running_total' and to check for the
last fragment (instead of num_trbs - which is now only used for
the call to prepare_transfer().
- No need to pass 'more_trbs_coming' to queue_trb(), it is implied
if TRB_CHAIN is set.
- Finish the loop when we failed to set TRB_CHAIN.
Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
---
drivers/usb/host/xhci-ring.c | 48 ++++++++++++++++++++------------------------
1 file changed, 22 insertions(+), 26 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d84b183..b60932b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3260,14 +3260,14 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
struct xhci_ring *ep_ring;
unsigned int num_trbs;
struct urb_priv *urb_priv;
- struct xhci_td *td;
struct scatterlist *sg;
int num_sgs;
int trb_buff_len, this_sg_len, running_total;
+ int len_left;
unsigned int total_packet_count;
bool first_trb;
u64 addr;
- bool more_trbs_coming;
+ int ret;
struct xhci_generic_trb *start_trb;
int start_cycle;
@@ -3281,14 +3281,12 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
total_packet_count = DIV_ROUND_UP(urb->transfer_buffer_length,
usb_endpoint_maxp(&urb->ep->desc));
- trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
+ ret = prepare_transfer(xhci, xhci->devs[slot_id],
ep_index, urb->stream_id,
num_trbs, urb, 0, mem_flags);
- if (trb_buff_len < 0)
- return trb_buff_len;
+ if (ret < 0)
+ return ret;
- urb_priv = urb->hcpriv;
- td = urb_priv->td[0];
/*
* Don't give the first TRB to the hardware (by toggling the cycle bit)
@@ -3299,6 +3297,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
start_cycle = ep_ring->cycle_state;
running_total = 0;
+ len_left = urb->transfer_buffer_length;
/*
* How much data is in the first TRB?
*
@@ -3318,7 +3317,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
first_trb = true;
/* Queue the first TRB, even if it's zero-length */
- do {
+ for (;;) {
u32 field = 0;
u32 length_field = 0;
u32 remainder = 0;
@@ -3334,11 +3333,12 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
/* Chain all the TRBs together; clear the chain bit in the last
* TRB to indicate it's the last TRB in the chain.
*/
- if (num_trbs > 1) {
+ if (trb_buff_len != len_left) {
field |= TRB_CHAIN;
} else {
/* FIXME - add check for ZERO_PACKET flag before this */
- td->last_trb = ep_ring->enqueue;
+ urb_priv = urb->hcpriv;
+ urb_priv->td[0]->last_trb = ep_ring->enqueue;
field |= TRB_IOC;
}
@@ -3348,29 +3348,28 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
/* Set the TRB length, TD size, and interrupter fields. */
if (xhci->hci_version < 0x100) {
- remainder = xhci_td_remainder(
- urb->transfer_buffer_length -
- running_total);
+ remainder = xhci_td_remainder(len_left);
} else {
remainder = xhci_v1_0_td_remainder(running_total,
trb_buff_len, total_packet_count, urb,
- num_trbs - 1);
+ trb_buff_len != len_left);
}
length_field = TRB_LEN(trb_buff_len) |
remainder |
TRB_INTR_TARGET(0);
- if (num_trbs > 1)
- more_trbs_coming = true;
- else
- more_trbs_coming = false;
- queue_trb(xhci, ep_ring, more_trbs_coming,
+ queue_trb(xhci, ep_ring, false,
lower_32_bits(addr),
upper_32_bits(addr),
length_field,
field | TRB_TYPE(TRB_NORMAL));
- --num_trbs;
+
+ /* If we didn't set the chain bit, we must have finished */
+ if (!(field & TRB_CHAIN))
+ break;
+
running_total += trb_buff_len;
+ len_left -= trb_buff_len;
/* Calculate length for next transfer --
* Are we done queueing all the TRBs for this sg entry?
@@ -3378,8 +3377,6 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
this_sg_len -= trb_buff_len;
if (this_sg_len == 0) {
--num_sgs;
- if (num_sgs == 0)
- break;
sg = sg_next(sg);
addr = (u64) sg_dma_address(sg);
this_sg_len = sg_dma_len(sg);
@@ -3390,10 +3387,9 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
trb_buff_len = TRB_MAX_BUFF_SIZE -
(addr & (TRB_MAX_BUFF_SIZE - 1));
trb_buff_len = min_t(int, trb_buff_len, this_sg_len);
- if (running_total + trb_buff_len > urb->transfer_buffer_length)
- trb_buff_len =
- urb->transfer_buffer_length - running_total;
- } while (running_total < urb->transfer_buffer_length);
+ if (trb_buff_len > len_left)
+ trb_buff_len = len_left;
+ }
giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
start_cycle, start_trb);
--
1.8.1.2
--
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