linux-kernel - Re: [PATCH v1 06/29] virtio-mem: generalize virtio_mem_owned

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Date:   Thu, 15 Oct 2020 16:32:34 +0800
From:   Wei Yang <richard.weiyang@...ux.alibaba.com>
To:     David Hildenbrand <david@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        virtualization@...ts.linux-foundation.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Pankaj Gupta <pankaj.gupta.linux@...il.com>
Subject: Re: [PATCH v1 06/29] virtio-mem: generalize virtio_mem_owned_mb()

On Mon, Oct 12, 2020 at 02:53:00PM +0200, David Hildenbrand wrote:
>Avoid using memory block ids. Rename it to virtio_mem_contains_range().
>
>Cc: "Michael S. Tsirkin" <mst@...hat.com>
>Cc: Jason Wang <jasowang@...hat.com>
>Cc: Pankaj Gupta <pankaj.gupta.linux@...il.com>
>Signed-off-by: David Hildenbrand <david@...hat.com>
>---
> drivers/virtio/virtio_mem.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
>index 6bbd1cfd10d3..821143db14fe 100644
>--- a/drivers/virtio/virtio_mem.c
>+++ b/drivers/virtio/virtio_mem.c
>@@ -500,12 +500,13 @@ static bool virtio_mem_overlaps_range(struct virtio_mem *vm,
> }
> 
> /*
>- * Test if a virtio-mem device owns a memory block. Can be called from
>+ * Test if a virtio-mem device contains a given range. Can be called from
>  * (notifier) callbacks lockless.
>  */
>-static bool virtio_mem_owned_mb(struct virtio_mem *vm, unsigned long mb_id)
>+static bool virtio_mem_contains_range(struct virtio_mem *vm, uint64_t start,
>+				      uint64_t size)
> {
>-	return mb_id >= vm->first_mb_id && mb_id <= vm->last_mb_id;
>+	return start >= vm->addr && start + size <= vm->addr + vm->region_size;

Do we have some reason to do this change?

> }
> 
> static int virtio_mem_notify_going_online(struct virtio_mem *vm,
>@@ -800,7 +801,7 @@ static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
> 	 */
> 	rcu_read_lock();
> 	list_for_each_entry_rcu(vm, &virtio_mem_devices, next) {
>-		if (!virtio_mem_owned_mb(vm, mb_id))
>+		if (!virtio_mem_contains_range(vm, addr, PFN_PHYS(1 << order)))
> 			continue;
> 
> 		sb_id = virtio_mem_phys_to_sb_id(vm, addr);
>-- 
>2.26.2

-- 
Wei Yang
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