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Commit 34b8886e authored by Maya Erez's avatar Maya Erez Committed by Kalle Valo
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wil6210: protect wil_vring_fini_tx in parallel to tx completions 



napi_synchronize is called before releasing the vring, with the
assumption that setting txdata->enabled to 0 will prevent handling
of this vring in the next scheduled napi.
To guarantee this assumption, a memory barrier is added after disabling
the txdata.
In addition, as the ctx is zeroed in wil_tx_complete after this
descriptor is handled (protected by wmb), ctx needs to be checked
before releasing this descriptor in wil_vring_free.

Signed-off-by: default avatarMaya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: default avatarKalle Valo <kvalo@qca.qualcomm.com>
parent ab6d7cc3

drivers/net/wireless/ath/wil6210/txrx.c

+14 −0
Original line number Diff line number Diff line
@@ -184,6 +184,13 @@ static void wil_vring_free(struct wil6210_priv *wil, struct vring *vring, 
					&vring->va[vring->swtail].tx;



			ctx = &vring->ctx[vring->swtail];

			if (!ctx) {

				wil_dbg_txrx(wil,

					     "ctx(%d) was already completed\n",

					     vring->swtail);

				vring->swtail = wil_vring_next_tail(vring);

				continue;

			}

			*d = *_d;

			wil_txdesc_unmap(dev, d, ctx);

			if (ctx->skb)
@@ -975,6 +982,13 @@ void wil_vring_fini_tx(struct wil6210_priv *wil, int id) 
	txdata->dot1x_open = false;

	txdata->enabled = 0; /* no Tx can be in progress or start anew */

	spin_unlock_bh(&txdata->lock);

	/* napi_synchronize waits for completion of the current NAPI but will

	 * not prevent the next NAPI run.

	 * Add a memory barrier to guarantee that txdata->enabled is zeroed

	 * before napi_synchronize so that the next scheduled NAPI will not

	 * handle this vring

	 */

	wmb();

	/* make sure NAPI won't touch this vring */

	if (test_bit(wil_status_napi_en, wil->status))

		napi_synchronize(&wil->napi_tx);