net: ethernet: mtk_wed: fix sleep while atomic in mtk_wed_wo_queue_refill

In order to fix the following sleep while atomic bug always alloc pages
with GFP_ATOMIC in mtk_wed_wo_queue_refill since page_frag_alloc runs in
spin_lock critical section.

[ 9.049719] Hardware name: MediaTek MT7986a RFB (DT)
[ 9.054665] Call trace:
[ 9.057096] dump_backtrace+0x0/0x154
[ 9.060751] show_stack+0x14/0x1c
[ 9.064052] dump_stack_lvl+0x64/0x7c
[ 9.067702] dump_stack+0x14/0x2c
[ 9.071001] ___might_sleep+0xec/0x120
[ 9.074736] __might_sleep+0x4c/0x9c
[ 9.078296] __alloc_pages+0x184/0x2e4
[ 9.082030] page_frag_alloc_align+0x98/0x1ac
[ 9.086369] mtk_wed_wo_queue_refill+0x134/0x234
[ 9.090974] mtk_wed_wo_init+0x174/0x2c0
[ 9.094881] mtk_wed_attach+0x7c8/0x7e0
[ 9.098701] mt7915_mmio_wed_init+0x1f0/0x3a0 [mt7915e]
[ 9.103940] mt7915_pci_probe+0xec/0x3bc [mt7915e]
[ 9.108727] pci_device_probe+0xac/0x13c
[ 9.112638] really_probe.part.0+0x98/0x2f4
[ 9.116807] __driver_probe_device+0x94/0x13c
[ 9.121147] driver_probe_device+0x40/0x114
[ 9.125314] __driver_attach+0x7c/0x180
[ 9.129133] bus_for_each_dev+0x5c/0x90
[ 9.132953] driver_attach+0x20/0x2c
[ 9.136513] bus_add_driver+0x104/0x1fc
[ 9.140333] driver_register+0x74/0x120
[ 9.144153] __pci_register_driver+0x40/0x50
[ 9.148407] mt7915_init+0x5c/0x1000 [mt7915e]
[ 9.152848] do_one_initcall+0x40/0x25c
[ 9.156669] do_init_module+0x44/0x230
[ 9.160403] load_module+0x1f30/0x2750
[ 9.164135] __do_sys_init_module+0x150/0x200
[ 9.168475] __arm64_sys_init_module+0x18/0x20
[ 9.172901] invoke_syscall.constprop.0+0x4c/0xe0
[ 9.177589] do_el0_svc+0x48/0xe0
[ 9.180889] el0_svc+0x14/0x50
[ 9.183929] el0t_64_sync_handler+0x9c/0x120
[ 9.188183] el0t_64_sync+0x158/0x15c

Fixes: 799684448e3e ("net: ethernet: mtk_wed: introduce wed wo support")
Signed-off-by: Lorenzo Bianconi <[e-mail]>
Reviewed-by: Pavan Chebbi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/mediatek/mtk_wed_wo.c

···
 
 static int
 mtk_wed_wo_queue_refill(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q,
-			gfp_t gfp, bool rx)
+			bool rx)
 {
 	enum dma_data_direction dir = rx ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 	int n_buf = 0;
 
 	spin_lock_bh(&q->lock);
 	while (q->queued < q->n_desc) {
-		void *buf = page_frag_alloc(&q->cache, q->buf_size, gfp);
 		struct mtk_wed_wo_queue_entry *entry;
 		dma_addr_t addr;
+		void *buf;
 
+		buf = page_frag_alloc(&q->cache, q->buf_size, GFP_ATOMIC);
 		if (!buf)
 			break;
 
···
 			mtk_wed_mcu_rx_unsolicited_event(wo, skb);
 	}
 
-	if (mtk_wed_wo_queue_refill(wo, q, GFP_ATOMIC, true)) {
+	if (mtk_wed_wo_queue_refill(wo, q, true)) {
 		u32 index = (q->head - 1) % q->n_desc;
 
 		mtk_wed_wo_queue_kick(wo, q, index);
···
 	if (ret)
 		goto error;
 
-	mtk_wed_wo_queue_refill(wo, &wo->q_tx, GFP_KERNEL, false);
+	mtk_wed_wo_queue_refill(wo, &wo->q_tx, false);
 	mtk_wed_wo_queue_reset(wo, &wo->q_tx);
 
 	regs.desc_base = MTK_WED_WO_CCIF_DUMMY5;
···
 	if (ret)
 		goto error;
 
-	mtk_wed_wo_queue_refill(wo, &wo->q_rx, GFP_KERNEL, true);
+	mtk_wed_wo_queue_refill(wo, &wo->q_rx, true);
 	mtk_wed_wo_queue_reset(wo, &wo->q_rx);
 
 	/* rx queue irqmask */