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| author | Fan Ye <fy15309206903@gmail.com> | 2026-08-10 12:14:13 +0000 |
|---|---|---|
| committer | Mika Westerberg <mika.westerberg@linux.intel.com> | 2026-08-11 05:57:59 +0200 |
| commit | 86feaba911f2f1a540a7695c8f4a98fd0fd60ac4 (patch) | |
| tree | ae97c0ecfe3da5f257a2b4bb14b62603d4ee1957 | |
| parent | e8158c8a6a232a70ae70c5acfaf7008a99b716c1 (diff) | |
| download | linux-stable-86feaba911f2f1a540a7695c8f4a98fd0fd60ac4.tar.gz linux-stable-86feaba911f2f1a540a7695c8f4a98fd0fd60ac4.zip | |
thunderbolt: Clamp DMA tunnel credits to what a hop register can hold
struct tb_regs_hop::initial_credits is 7 bits wide, but neither of the
values tb_tunnel_alloc_dma() picks from is bounded by that: the
dma_credits module parameter has no upper limit, and neither does the
host router's baMaxHI. A larger count survives until tb_path_activate()
copies it into the register and keeps the low bits, leaving the path on
a credit count nobody asked for.
Clamp it in tb_tunnel_alloc_dma(), the only entry point for DMA tunnels;
every step below it can only lower the value further. Carry the count in
an unsigned int while at it.
Assisted-by: Claude:claude-opus-5
Signed-off-by: Fan Ye <fy15309206903@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
| -rw-r--r-- | drivers/thunderbolt/tunnel.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c index e9214de5f3b7..7e8284575dff 100644 --- a/drivers/thunderbolt/tunnel.c +++ b/drivers/thunderbolt/tunnel.c @@ -48,6 +48,9 @@ #define TB_DP_AUX_PRIORITY 2 #define TB_DP_AUX_WEIGHT 1 +/* struct tb_regs_hop::initial_credits is 7 bits wide */ +#define TB_MAX_CREDITS 127 + /* Minimum number of credits needed for PCIe path */ #define TB_MIN_PCIE_CREDITS 6U /* @@ -1907,7 +1910,7 @@ struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi, struct tb_tunnel *tunnel; size_t npaths = 0, i = 0; struct tb_path *path; - int credits; + unsigned int credits; /* Ring 0 is reserved for control channel */ if (WARN_ON(!receive_ring || !transmit_ring)) @@ -1930,6 +1933,11 @@ struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi, tunnel->destroy = tb_dma_destroy; credits = min_not_zero(dma_credits, nhi->sw->max_dma_credits); + if (credits > TB_MAX_CREDITS) { + tb_tunnel_dbg(tunnel, "%u credits do not fit a hop, using %u\n", + credits, TB_MAX_CREDITS); + credits = TB_MAX_CREDITS; + } if (receive_ring > 0) { path = tb_path_alloc(tb, dst, receive_path, nhi, receive_ring, 0, |