nvmet: use new ana_log_size instead the old one

The new ana_log_size should be used instead of the old one.
Or kernel NULL pointer dereference will happen like below:

[   38.957849][   T69] BUG: kernel NULL pointer dereference, address: 000000000000003c
[   38.975550][   T69] #PF: supervisor write access in kernel mode
[   38.975955][   T69] #PF: error_code(0x0002) - not-present page
[   38.976905][   T69] PGD 0 P4D 0
[   38.979388][   T69] Oops: 0002 [#1] SMP NOPTI
[   38.980488][   T69] CPU: 0 PID: 69 Comm: kworker/0:2 Not tainted 5.12.0+ #54
[   38.981254][   T69] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[   38.982502][   T69] Workqueue: events nvme_loop_execute_work
[   38.985219][   T69] RIP: 0010:memcpy_orig+0x68/0x10f
[   38.986203][   T69] Code: 83 c2 20 eb 44 48 01 d6 48 01 d7 48 83 ea 20 0f 1f 00 48 83 ea 20 4c 8b 46 f8 4c 8b 4e f0 4c 8b 56 e8 4c 8b 5e e0 48 8d 76 e0 <4c> 89 47 f8 4c 89 4f f0 4c 89 57 e8 4c 89 5f e0 48 8d 7f e0 73 d2
[   38.987677][   T69] RSP: 0018:ffffc900001b7d48 EFLAGS: 00000287
[   38.987996][   T69] RAX: 0000000000000020 RBX: 0000000000000024 RCX: 0000000000000010
[   38.988327][   T69] RDX: ffffffffffffffe4 RSI: ffff8881084bc004 RDI: 0000000000000044
[   38.988620][   T69] RBP: 0000000000000024 R08: 0000000100000000 R09: 0000000000000000
[   38.988991][   T69] R10: 0000000100000000 R11: 0000000000000001 R12: 0000000000000024
[   38.989289][   T69] R13: ffff8881084bc000 R14: 0000000000000000 R15: 0000000000000024
[   38.989845][   T69] FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
[   38.990234][   T69] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   38.990490][   T69] CR2: 000000000000003c CR3: 00000001085b2000 CR4: 00000000000006f0
[   38.991105][   T69] Call Trace:
[   38.994157][   T69]  sg_copy_buffer+0xb8/0xf0
[   38.995357][   T69]  nvmet_copy_to_sgl+0x48/0x6d
[   38.995565][   T69]  nvmet_execute_get_log_page_ana+0xd4/0x1cb
[   38.995792][   T69]  nvmet_execute_get_log_page+0xc9/0x146
[   38.995992][   T69]  nvme_loop_execute_work+0x3e/0x44
[   38.996181][   T69]  process_one_work+0x1c3/0x3c0
[   38.996393][   T69]  worker_thread+0x44/0x3d0
[   38.996600][   T69]  ? cancel_delayed_work+0x90/0x90
[   38.996804][   T69]  kthread+0xf7/0x130
[   38.996961][   T69]  ? kthread_create_worker_on_cpu+0x70/0x70
[   38.997171][   T69]  ret_from_fork+0x22/0x30
[   38.997705][   T69] Modules linked in:
[   38.998741][   T69] CR2: 000000000000003c
[   39.000104][   T69] ---[ end trace e719927b609d0fa0 ]---

Fixes: 5e1f6899 ("nvme-multipath: fix double initialization of ANA state")
Signed-off-by: Hou Pu <houpu.main@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/multipath.c

@@ -817,7 +817,7 @@ int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	if (ana_log_size > ctrl->ana_log_size) {
 		nvme_mpath_stop(ctrl);
 		kfree(ctrl->ana_log_buf);
-		ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
+		ctrl->ana_log_buf = kmalloc(ana_log_size, GFP_KERNEL);
 		if (!ctrl->ana_log_buf)
 			return -ENOMEM;
 	}