net: cadence: macb: disable NAPI on error

When the PHY is not working, the macb driver crash on a second try to
setup it.
[   78.545994] macb e000b000.ethernet eth0: Could not attach PHY (-19)
ifconfig: SIOCSIFFLAGS: No such device
[   78.655457] ------------[ cut here ]------------
[   78.656014] kernel BUG at /linux-next/include/linux/netdevice.h:521!
[   78.656504] Internal error: Oops - BUG: 0 [#1] SMP ARM
[   78.657079] Modules linked in:
[   78.657795] CPU: 0 PID: 122 Comm: ifconfig Not tainted 5.7.0-next-20200609 #1
[   78.658202] Hardware name: Xilinx Zynq Platform
[   78.659632] PC is at macb_open+0x220/0x294
[   78.660160] LR is at 0x0
[   78.660373] pc : [<c0b0a634>]    lr : [<00000000>]    psr: 60000013
[   78.660716] sp : c89ffd70  ip : c8a28800  fp : c199bac0
[   78.661040] r10: 00000000  r9 : c8838540  r8 : c8838568
[   78.661362] r7 : 00000001  r6 : c8838000  r5 : c883c000  r4 : 00000000
[   78.661724] r3 : 00000010  r2 : 00000000  r1 : 00000000  r0 : 00000000
[   78.662187] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[   78.662635] Control: 10c5387d  Table: 08b64059  DAC: 00000051
[   78.663035] Process ifconfig (pid: 122, stack limit = 0x(ptrval))
[   78.663476] Stack: (0xc89ffd70 to 0xc8a00000)
[   78.664121] fd60:                                     00000000 c89fe000 c8838000 c89fe000
[   78.664866] fd80: 00000000 c11ff9ac c8838028 00000000 00000000 c0de6f2c 00000001 c1804eec
[   78.665579] fda0: c19b8178 c8838000 00000000 ca760866 c8838000 00000001 00001043 c89fe000
[   78.666355] fdc0: 00001002 c0de72f4 c89fe000 c0de8dc0 00008914 c89fe000 c199bac0 ca760866
[   78.667111] fde0: c89ffddc c8838000 00001002 00000000 c8838138 c881010c 00008914 c0de7364
[   78.667862] fe00: 00000000 c89ffe70 c89fe000 ffffffff c881010c c0e8bd48 00000003 00000000
[   78.668601] fe20: c8838000 c8810100 39c1118f 00039c11 c89a0960 00001043 00000000 000a26d0
[   78.669343] fe40: b6f43000 ca760866 c89a0960 00000051 befe6c50 00008914 c8b2a3c0 befe6c50
[   78.670086] fe60: 00000003 ee610500 00000000 c0e8ef58 30687465 00000000 00000000 00000000
[   78.670865] fe80: 00001043 00000000 000a26d0 b6f43000 c89a0600 ee40ae7c c8870d00 c0ddabf4
[   78.671593] fea0: c89ffeec c0ddabf4 c89ffeec c199bac0 00008913 c0ddac48 c89ffeec c89fe000
[   78.672324] fec0: befe6c50 ca760866 befe6c50 00008914 c89fe000 befe6c50 c8b2a3c0 c0dc00e4
[   78.673088] fee0: c89a0480 00000201 00000cc0 30687465 00000000 00000000 00000000 00001002
[   78.673822] ff00: 00000000 000a26d0 b6f43000 ca760866 00008914 c8b2a3c0 000a0ec4 c8b2a3c0
[   78.674576] ff20: befe6c50 c04b21bc 000d5004 00000817 c89a0480 c0315f94 00000000 00000003
[   78.675415] ff40: c19a2bc8 c8a3cc00 c89fe000 00000255 00000000 00000000 00000000 000d5000
[   78.676182] ff60: 000f6000 c180b2a0 00000817 c0315e64 000d5004 c89fffb0 b6ec0c30 ca760866
[   78.676928] ff80: 00000000 000b609b befe6c50 000a0ec4 00000036 c03002c4 c89fe000 00000036
[   78.677673] ffa0: 00000000 c03000c0 000b609b befe6c50 00000003 00008914 befe6c50 000b609b
[   78.678415] ffc0: 000b609b befe6c50 000a0ec4 00000036 befe6e0c befe6f1a 000d5150 00000000
[   78.679154] ffe0: 000d41e4 befe6bf4 00019648 b6e4509c 20000010 00000003 00000000 00000000
[   78.681059] [<c0b0a634>] (macb_open) from [<c0de6f2c>] (__dev_open+0xd0/0x154)
[   78.681571] [<c0de6f2c>] (__dev_open) from [<c0de72f4>] (__dev_change_flags+0x16c/0x1c4)
[   78.682015] [<c0de72f4>] (__dev_change_flags) from [<c0de7364>] (dev_change_flags+0x18/0x48)
[   78.682493] [<c0de7364>] (dev_change_flags) from [<c0e8bd48>] (devinet_ioctl+0x5e4/0x75c)
[   78.682945] [<c0e8bd48>] (devinet_ioctl) from [<c0e8ef58>] (inet_ioctl+0x1f0/0x3b4)
[   78.683381] [<c0e8ef58>] (inet_ioctl) from [<c0dc00e4>] (sock_ioctl+0x39c/0x664)
[   78.683818] [<c0dc00e4>] (sock_ioctl) from [<c04b21bc>] (ksys_ioctl+0x2d8/0x9c0)
[   78.684343] [<c04b21bc>] (ksys_ioctl) from [<c03000c0>] (ret_fast_syscall+0x0/0x54)
[   78.684789] Exception stack(0xc89fffa8 to 0xc89ffff0)
[   78.685346] ffa0:                   000b609b befe6c50 00000003 00008914 befe6c50 000b609b
[   78.686106] ffc0: 000b609b befe6c50 000a0ec4 00000036 befe6e0c befe6f1a 000d5150 00000000
[   78.686710] ffe0: 000d41e4 befe6bf4 00019648 b6e4509c
[   78.687582] Code: 9a000003 e5983078 e3130001 1affffef (e7f001f2)
[   78.688788] ---[ end trace e3f2f6ab69754eae ]---

This is due to NAPI left enabled if macb_phylink_connect() fail.

Fixes: 7897b071 ("net: macb: convert to phylink")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb_main.c

@@ -2558,13 +2558,16 @@ static int macb_open(struct net_device *dev)
 
 	err = macb_phylink_connect(bp);
 	if (err)
-		goto pm_exit;
+		goto napi_exit;
 
 	netif_tx_start_all_queues(dev);
 
 	if (bp->ptp_info)
 		bp->ptp_info->ptp_init(dev);
 
+napi_exit:
+	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
+		napi_disable(&queue->napi);
 pm_exit:
 	if (err) {
 		pm_runtime_put_sync(&bp->pdev->dev);