[PATCH net-next v4 1/4] net: mana: track when the HWC has been handed to the PF
From: Long Li
Date: Tue Sep 01 2026 - 16:18:55 EST
mana_hwc_destroy_channel() decides whether to tear the channel down by
looking at gc->max_num_cqs, which is only set when the device delivers an
HWC_INIT_DATA_MAX_NUM_CQS bootstrap event. That is a proxy for "the
device is using the queues", and it is a poor one: the event arrives well
after mana_smc_setup_hwc() has already handed the queue addresses to the
PF, so a setup that fails in between leaves no reliable signal.
Record the handover directly instead. mana_smc_setup_hwc() clears the
new setup_active flag on entry and sets it immediately before it writes
the ESTABLISH_HWC message, so the flag is exact in both directions: the
three exits before that write leave the device untouched and clear the
flag, while everything after it -- including a failed response -- leaves
it set, because the PF has the queue addresses either way.
No functional change is intended for the current single-establish flow.
This is preparation for the reinit path added later in this series, which
tears the channel down and rebuilds it at a larger queue depth and needs
to know whether a given attempt left the device holding the queues.
Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
---
.../net/ethernet/microsoft/mana/hw_channel.c | 19 +++++++++++++------
.../net/ethernet/microsoft/mana/shm_channel.c | 11 ++++++++++-
include/net/mana/hw_channel.h | 10 ++++++++++
include/net/mana/shm_channel.h | 2 +-
4 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c b/drivers/net/ethernet/microsoft/mana/hw_channel.c
index 263e7c4e2934186af037be4c80350a6e322b6771..75fdccdc8c48201b011a243fd0bd41b84c477076 100644
--- a/drivers/net/ethernet/microsoft/mana/hw_channel.c
+++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c
@@ -683,7 +683,7 @@ static int mana_hwc_establish_channel(struct gdma_context *gc, u16 *q_depth,
cq->mem_info.dma_handle,
rq->mem_info.dma_handle,
sq->mem_info.dma_handle,
- eq->eq.msix_index);
+ eq->eq.msix_index, &hwc->setup_active);
if (err)
return err;
@@ -815,13 +815,20 @@ void mana_hwc_destroy_channel(struct gdma_context *gc)
if (!hwc)
return;
- /* gc->max_num_cqs is set in mana_hwc_init_event_handler(). If it's
- * non-zero, the HWC worked and we should tear down the HWC here.
+ /* Tear down only if setup_hwc() handed the queues to the PF. Until
+ * then the device never saw them, so there is nothing to undo.
*/
- if (gc->max_num_cqs > 0) {
- mana_smc_teardown_hwc(&gc->shm_channel, false);
- gc->max_num_cqs = 0;
+ if (hwc->setup_active) {
+ /* Only a successful teardown invalidates the MST entries. If
+ * it fails the device may still be using the queues, so leave
+ * the flag set rather than record a clean teardown.
+ */
+ if (!mana_smc_teardown_hwc(&gc->shm_channel, false))
+ hwc->setup_active = false;
+ else
+ dev_err(hwc->dev, "Failed to tear down HWC\n");
}
+ gc->max_num_cqs = 0;
if (hwc->txq)
mana_hwc_destroy_wq(hwc, hwc->txq);
diff --git a/drivers/net/ethernet/microsoft/mana/shm_channel.c b/drivers/net/ethernet/microsoft/mana/shm_channel.c
index d21b5db06e5092d82249fb1053d07f65aa38490c..1ec8e3661721dc8663975477b7ed09fcda72e2ab 100644
--- a/drivers/net/ethernet/microsoft/mana/shm_channel.c
+++ b/drivers/net/ethernet/microsoft/mana/shm_channel.c
@@ -129,9 +129,15 @@ void mana_smc_init(struct shm_channel *sc, struct device *dev,
sc->base = base;
}
+/* Clear *submitted on entry and set it once the ESTABLISH_HWC message has
+ * been handed to the PF, i.e. once the device may start using the queues.
+ * The caller uses it to decide whether a failure still needs
+ * mana_smc_teardown_hwc(): the exits below leave the device untouched, so
+ * they must not require one.
+ */
int mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, u64 eq_addr,
u64 cq_addr, u64 rq_addr, u64 sq_addr,
- u32 eq_msix_index)
+ u32 eq_msix_index, bool *submitted)
{
union smc_proto_hdr *hdr;
u16 all_addr_h4bits = 0;
@@ -144,6 +150,8 @@ int mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, u64 eq_addr,
int err;
int i;
+ *submitted = false;
+
/* Ensure VF already has possession of shared memory */
err = mana_smc_poll_register(sc->base, false);
if (err) {
@@ -229,6 +237,7 @@ int mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, u64 eq_addr,
/* Write 256-message buffer to shared memory (final 32-bit write
* triggers HW to set possession bit to PF).
*/
+ *submitted = true;
dword = (u32 *)shm_buf;
for (i = 0; i < SMC_APERTURE_DWORDS; i++)
writel(*dword++, sc->base + i * SMC_BASIC_UNIT);
diff --git a/include/net/mana/hw_channel.h b/include/net/mana/hw_channel.h
index 16feb39616c1bead1a043b3fadc2e18a90651516..237608b488e5ee773d7889d3c1d291ca92ebbeb9 100644
--- a/include/net/mana/hw_channel.h
+++ b/include/net/mana/hw_channel.h
@@ -199,6 +199,16 @@ struct hw_channel_context {
u32 pf_dest_vrcq_id;
u32 hwc_timeout;
+ /* True once mana_smc_setup_hwc() has handed the ESTABLISH_HWC message
+ * to the PF, so the device may DMA into the HWC buffers. That
+ * function clears it on entry and sets it at the handover, so only a
+ * failure before the handover leaves it false; a failure after it --
+ * including one reported by mana_hwc_establish_channel() -- leaves it
+ * set, which is what makes teardown attempt DESTROY_HWC. Cleared
+ * again once that teardown succeeds.
+ */
+ bool setup_active;
+
struct hwc_caller_ctx *caller_ctx;
};
diff --git a/include/net/mana/shm_channel.h b/include/net/mana/shm_channel.h
index dbabcfb95daf3e87b39a657e3a5f23a1508d4f31..e96387d795259d52aeec7b3fe0981825d90a3822 100644
--- a/include/net/mana/shm_channel.h
+++ b/include/net/mana/shm_channel.h
@@ -20,7 +20,7 @@ void mana_smc_init(struct shm_channel *sc, struct device *dev,
int mana_smc_setup_hwc(struct shm_channel *sc, bool reset_vf, u64 eq_addr,
u64 cq_addr, u64 rq_addr, u64 sq_addr,
- u32 eq_msix_index);
+ u32 eq_msix_index, bool *submitted);
int mana_smc_teardown_hwc(struct shm_channel *sc, bool reset_vf);
--
2.43.0