Merge branch 'fix-page-fragment-handling-when-page_size-4k'

Dimitri Daskalakis says:

====================
Fix page fragment handling when PAGE_SIZE > 4K

FBNIC operates on fixed size descriptors (4K). When the OS supports pages
larger than 4K, we fragment the page across multiple descriptors.

While performance testing, I found several issues with our page fragment
handling, resulting in low throughput and potential RX stalls.
====================

Link: https://patch.msgid.link/20260324195123.3486219-1-dimitri.daskalakis1@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c

@@ -197,7 +197,7 @@ static int fbnic_dbg_bdq_desc_seq_show(struct seq_file *s, void *v)
 		return 0;
 	}
 
-	for (i = 0; i <= ring->size_mask; i++) {
+	for (i = 0; i < (ring->size_mask + 1) * FBNIC_BD_FRAG_COUNT; i++) {
 		u64 bd = le64_to_cpu(ring->desc[i]);
 
 		seq_printf(s, "%04x %#04llx %#014llx\n", i,

drivers/net/ethernet/meta/fbnic/fbnic_txrx.c

@@ -927,7 +927,7 @@ static void fbnic_fill_bdq(struct fbnic_ring *bdq)
 		/* Force DMA writes to flush before writing to tail */
 		dma_wmb();
 
-		writel(i, bdq->doorbell);
+		writel(i * FBNIC_BD_FRAG_COUNT, bdq->doorbell);
 	}
 }
 
@@ -2564,7 +2564,7 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq)
 	hpq->tail = 0;
 	hpq->head = 0;
 
-	log_size = fls(hpq->size_mask);
+	log_size = fls(hpq->size_mask) + ilog2(FBNIC_BD_FRAG_COUNT);
 
 	/* Store descriptor ring address and size */
 	fbnic_ring_wr32(hpq, FBNIC_QUEUE_BDQ_HPQ_BAL, lower_32_bits(hpq->dma));
@@ -2576,7 +2576,7 @@ static void fbnic_enable_bdq(struct fbnic_ring *hpq, struct fbnic_ring *ppq)
 	if (!ppq->size_mask)
 		goto write_ctl;
 
-	log_size = fls(ppq->size_mask);
+	log_size = fls(ppq->size_mask) + ilog2(FBNIC_BD_FRAG_COUNT);
 
 	/* Add enabling of PPQ to BDQ control */
 	bdq_ctl |= FBNIC_QUEUE_BDQ_CTL_PPQ_ENABLE;