Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
On 10/19/2015 05:36 PM, Roger Pau Monné wrote: > El 10/10/15 a les 6.08, Bob Liu ha escrit: >> On 10/05/2015 10:55 PM, Roger Pau Monné wrote: >>> The same for the pool of persistent grants, it should be per-device and >>> not per-ring. >>> >>> And I think this issue is far worse than the others, because a frontend >>> might use a persistent grant on different queues, forcing the backend >>> map the grant several times for each queue, this is not acceptable IMO. >>> >> >> Hi Roger, >> >> I realize it would make things complicate if making persistent grant >> per-device instead of per-queue. >> Extra locks are required to protect the per-device pool on both blkfront and >> blkback. > > Yes, I realize this, but without having at least a prototype it's hard > to tell if contention is going to be a problem or not. We already use a > red-black tree to store persistent grants, which should be quite fast > when performing searches. > > IMHO, we are doing things backwards, we should have investigated first > if using per-device was a problem, and if it indeed was a problem then > move to per-queue. Using per-device just required adding locks around > the functions to get/put grants and friends, leaving the data structures > untouched (per-device). > >> AFAIR, there was a discussion before about dropping persistent grant map at >> all. >> The only reason we left this feature was backward compatibility. >> So that I think we should not complicate xen-block code any more because of >> a going to be dropped feature. >> >> How about disable feature-persistent if multi-queue was used? > > This is not what we have done in the past, also there's no way for > blkback to tell the frontend that persistent grants and multiqueue > cannot be used at the same time. Blkback puts all supported features on > xenstore before knowing anything about the frontend. > > Also, if you want to do it per-queue instead of per-device the limits > need to be properly adjusted, not just the persistent grants one, but > also the queue of cached free pages. This also implies that each queue > it's going to have it's own LRU and purge task. > Okay, then I'll update with a per-device version. For blkfront there would be two locks used, one for per-device and the other for per-ring. For blkback, an new lock would be added to protect the red-black tree e.g. in add_persistent_gnt(). -- Regards, -Bob ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
El 10/10/15 a les 6.08, Bob Liu ha escrit: > On 10/05/2015 10:55 PM, Roger Pau Monné wrote: >> The same for the pool of persistent grants, it should be per-device and >> not per-ring. >> >> And I think this issue is far worse than the others, because a frontend >> might use a persistent grant on different queues, forcing the backend >> map the grant several times for each queue, this is not acceptable IMO. >> > > Hi Roger, > > I realize it would make things complicate if making persistent grant > per-device instead of per-queue. > Extra locks are required to protect the per-device pool on both blkfront and > blkback. Yes, I realize this, but without having at least a prototype it's hard to tell if contention is going to be a problem or not. We already use a red-black tree to store persistent grants, which should be quite fast when performing searches. IMHO, we are doing things backwards, we should have investigated first if using per-device was a problem, and if it indeed was a problem then move to per-queue. Using per-device just required adding locks around the functions to get/put grants and friends, leaving the data structures untouched (per-device). > AFAIR, there was a discussion before about dropping persistent grant map at > all. > The only reason we left this feature was backward compatibility. > So that I think we should not complicate xen-block code any more because of a > going to be dropped feature. > > How about disable feature-persistent if multi-queue was used? This is not what we have done in the past, also there's no way for blkback to tell the frontend that persistent grants and multiqueue cannot be used at the same time. Blkback puts all supported features on xenstore before knowing anything about the frontend. Also, if you want to do it per-queue instead of per-device the limits need to be properly adjusted, not just the persistent grants one, but also the queue of cached free pages. This also implies that each queue it's going to have it's own LRU and purge task. Roger. ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
On 10/05/2015 10:55 PM, Roger Pau Monné wrote:
> El 05/09/15 a les 14.39, Bob Liu ha escrit:
>> Split per ring information to an new structure:xen_blkif_ring, so that one
>> vbd
>> device can associate with one or more rings/hardware queues.
>>
>> This patch is a preparation for supporting multi hardware queues/rings.
>>
>> Signed-off-by: Arianna Avanzini
>> Signed-off-by: Bob Liu
>> ---
>> drivers/block/xen-blkback/blkback.c | 365
>> ++-
>> drivers/block/xen-blkback/common.h | 52 +++--
>> drivers/block/xen-blkback/xenbus.c | 130 +++--
>> 3 files changed, 295 insertions(+), 252 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkback/blkback.c
>> b/drivers/block/xen-blkback/blkback.c
>> index 954c002..fd02240 100644
>> --- a/drivers/block/xen-blkback/blkback.c
>> +++ b/drivers/block/xen-blkback/blkback.c
>> @@ -113,71 +113,71 @@ module_param(log_stats, int, 0644);
>> /* Number of free pages to remove on each call to gnttab_free_pages */
>> #define NUM_BATCH_FREE_PAGES 10
>>
>> -static inline int get_free_page(struct xen_blkif *blkif, struct page **page)
>> +static inline int get_free_page(struct xen_blkif_ring *ring, struct page
>> **page)
>> {
>> unsigned long flags;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> -if (list_empty(&blkif->free_pages)) {
>> -BUG_ON(blkif->free_pages_num != 0);
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> +if (list_empty(&ring->free_pages)) {
>
> I'm afraid the pool of free pages should be per-device, not per-ring.
>
>> +BUG_ON(ring->free_pages_num != 0);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> return gnttab_alloc_pages(1, page);
>> }
>> -BUG_ON(blkif->free_pages_num == 0);
>> -page[0] = list_first_entry(&blkif->free_pages, struct page, lru);
>> +BUG_ON(ring->free_pages_num == 0);
>> +page[0] = list_first_entry(&ring->free_pages, struct page, lru);
>> list_del(&page[0]->lru);
>> -blkif->free_pages_num--;
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +ring->free_pages_num--;
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>>
>> return 0;
>> }
>>
>> -static inline void put_free_pages(struct xen_blkif *blkif, struct page
>> **page,
>> +static inline void put_free_pages(struct xen_blkif_ring *ring, struct page
>> **page,
>>int num)
>> {
>> unsigned long flags;
>> int i;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> for (i = 0; i < num; i++)
>> -list_add(&page[i]->lru, &blkif->free_pages);
>> -blkif->free_pages_num += num;
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +list_add(&page[i]->lru, &ring->free_pages);
>> +ring->free_pages_num += num;
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> }
>>
>> -static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num)
>> +static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int
>> num)
>> {
>> /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
>> struct page *page[NUM_BATCH_FREE_PAGES];
>> unsigned int num_pages = 0;
>> unsigned long flags;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> -while (blkif->free_pages_num > num) {
>> -BUG_ON(list_empty(&blkif->free_pages));
>> -page[num_pages] = list_first_entry(&blkif->free_pages,
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> +while (ring->free_pages_num > num) {
>> +BUG_ON(list_empty(&ring->free_pages));
>> +page[num_pages] = list_first_entry(&ring->free_pages,
>> struct page, lru);
>> list_del(&page[num_pages]->lru);
>> -blkif->free_pages_num--;
>> +ring->free_pages_num--;
>> if (++num_pages == NUM_BATCH_FREE_PAGES) {
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> gnttab_free_pages(num_pages, page);
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> num_pages = 0;
>> }
>> }
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> if (num_pages != 0)
>> gnttab_free_pages(num_pages, page);
>> }
>>
>> #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
>>
>> -static int do_block_io_op(struct xen_blkif *blkif);
>> -static int dispa
Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
On 10/05/2015 10:55 PM, Roger Pau Monné wrote:
> El 05/09/15 a les 14.39, Bob Liu ha escrit:
>> Split per ring information to an new structure:xen_blkif_ring, so that one
>> vbd
>> device can associate with one or more rings/hardware queues.
>>
>> This patch is a preparation for supporting multi hardware queues/rings.
>>
>> Signed-off-by: Arianna Avanzini
>> Signed-off-by: Bob Liu
>> ---
>> drivers/block/xen-blkback/blkback.c | 365
>> ++-
>> drivers/block/xen-blkback/common.h | 52 +++--
>> drivers/block/xen-blkback/xenbus.c | 130 +++--
>> 3 files changed, 295 insertions(+), 252 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkback/blkback.c
>> b/drivers/block/xen-blkback/blkback.c
>> index 954c002..fd02240 100644
>> --- a/drivers/block/xen-blkback/blkback.c
>> +++ b/drivers/block/xen-blkback/blkback.c
>> @@ -113,71 +113,71 @@ module_param(log_stats, int, 0644);
>> /* Number of free pages to remove on each call to gnttab_free_pages */
>> #define NUM_BATCH_FREE_PAGES 10
>>
>> -static inline int get_free_page(struct xen_blkif *blkif, struct page **page)
>> +static inline int get_free_page(struct xen_blkif_ring *ring, struct page
>> **page)
>> {
>> unsigned long flags;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> -if (list_empty(&blkif->free_pages)) {
>> -BUG_ON(blkif->free_pages_num != 0);
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> +if (list_empty(&ring->free_pages)) {
>
> I'm afraid the pool of free pages should be per-device, not per-ring.
>
>> +BUG_ON(ring->free_pages_num != 0);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> return gnttab_alloc_pages(1, page);
>> }
>> -BUG_ON(blkif->free_pages_num == 0);
>> -page[0] = list_first_entry(&blkif->free_pages, struct page, lru);
>> +BUG_ON(ring->free_pages_num == 0);
>> +page[0] = list_first_entry(&ring->free_pages, struct page, lru);
>> list_del(&page[0]->lru);
>> -blkif->free_pages_num--;
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +ring->free_pages_num--;
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>>
>> return 0;
>> }
>>
>> -static inline void put_free_pages(struct xen_blkif *blkif, struct page
>> **page,
>> +static inline void put_free_pages(struct xen_blkif_ring *ring, struct page
>> **page,
>>int num)
>> {
>> unsigned long flags;
>> int i;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> for (i = 0; i < num; i++)
>> -list_add(&page[i]->lru, &blkif->free_pages);
>> -blkif->free_pages_num += num;
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +list_add(&page[i]->lru, &ring->free_pages);
>> +ring->free_pages_num += num;
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> }
>>
>> -static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num)
>> +static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int
>> num)
>> {
>> /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
>> struct page *page[NUM_BATCH_FREE_PAGES];
>> unsigned int num_pages = 0;
>> unsigned long flags;
>>
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> -while (blkif->free_pages_num > num) {
>> -BUG_ON(list_empty(&blkif->free_pages));
>> -page[num_pages] = list_first_entry(&blkif->free_pages,
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> +while (ring->free_pages_num > num) {
>> +BUG_ON(list_empty(&ring->free_pages));
>> +page[num_pages] = list_first_entry(&ring->free_pages,
>> struct page, lru);
>> list_del(&page[num_pages]->lru);
>> -blkif->free_pages_num--;
>> +ring->free_pages_num--;
>> if (++num_pages == NUM_BATCH_FREE_PAGES) {
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> gnttab_free_pages(num_pages, page);
>> -spin_lock_irqsave(&blkif->free_pages_lock, flags);
>> +spin_lock_irqsave(&ring->free_pages_lock, flags);
>> num_pages = 0;
>> }
>> }
>> -spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
>> +spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>> if (num_pages != 0)
>> gnttab_free_pages(num_pages, page);
>> }
>>
>> #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
>>
>> -static int do_block_io_op(struct xen_blkif *blkif);
>> -static int dispa
Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
El 05/09/15 a les 14.39, Bob Liu ha escrit:
> Split per ring information to an new structure:xen_blkif_ring, so that one vbd
> device can associate with one or more rings/hardware queues.
>
> This patch is a preparation for supporting multi hardware queues/rings.
>
> Signed-off-by: Arianna Avanzini
> Signed-off-by: Bob Liu
> ---
> drivers/block/xen-blkback/blkback.c | 365
> ++-
> drivers/block/xen-blkback/common.h | 52 +++--
> drivers/block/xen-blkback/xenbus.c | 130 +++--
> 3 files changed, 295 insertions(+), 252 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/blkback.c
> b/drivers/block/xen-blkback/blkback.c
> index 954c002..fd02240 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -113,71 +113,71 @@ module_param(log_stats, int, 0644);
> /* Number of free pages to remove on each call to gnttab_free_pages */
> #define NUM_BATCH_FREE_PAGES 10
>
> -static inline int get_free_page(struct xen_blkif *blkif, struct page **page)
> +static inline int get_free_page(struct xen_blkif_ring *ring, struct page
> **page)
> {
> unsigned long flags;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> - if (list_empty(&blkif->free_pages)) {
> - BUG_ON(blkif->free_pages_num != 0);
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> + if (list_empty(&ring->free_pages)) {
I'm afraid the pool of free pages should be per-device, not per-ring.
> + BUG_ON(ring->free_pages_num != 0);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> return gnttab_alloc_pages(1, page);
> }
> - BUG_ON(blkif->free_pages_num == 0);
> - page[0] = list_first_entry(&blkif->free_pages, struct page, lru);
> + BUG_ON(ring->free_pages_num == 0);
> + page[0] = list_first_entry(&ring->free_pages, struct page, lru);
> list_del(&page[0]->lru);
> - blkif->free_pages_num--;
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + ring->free_pages_num--;
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>
> return 0;
> }
>
> -static inline void put_free_pages(struct xen_blkif *blkif, struct page
> **page,
> +static inline void put_free_pages(struct xen_blkif_ring *ring, struct page
> **page,
>int num)
> {
> unsigned long flags;
> int i;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> for (i = 0; i < num; i++)
> - list_add(&page[i]->lru, &blkif->free_pages);
> - blkif->free_pages_num += num;
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + list_add(&page[i]->lru, &ring->free_pages);
> + ring->free_pages_num += num;
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> }
>
> -static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num)
> +static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num)
> {
> /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
> struct page *page[NUM_BATCH_FREE_PAGES];
> unsigned int num_pages = 0;
> unsigned long flags;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> - while (blkif->free_pages_num > num) {
> - BUG_ON(list_empty(&blkif->free_pages));
> - page[num_pages] = list_first_entry(&blkif->free_pages,
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> + while (ring->free_pages_num > num) {
> + BUG_ON(list_empty(&ring->free_pages));
> + page[num_pages] = list_first_entry(&ring->free_pages,
> struct page, lru);
> list_del(&page[num_pages]->lru);
> - blkif->free_pages_num--;
> + ring->free_pages_num--;
> if (++num_pages == NUM_BATCH_FREE_PAGES) {
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> gnttab_free_pages(num_pages, page);
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> num_pages = 0;
> }
> }
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> if (num_pages != 0)
> gnttab_free_pages(num_pages, page);
> }
>
> #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
>
> -static int do_block_io_op(struct xen_blkif *blkif);
> -static int dispatch_rw_block_io(struct xen_blkif *blkif,
> +static int do_block_io_op(struct xen_blkif_ring *ring);
> +static i
Re: [Xen-devel] [PATCH v3 7/9] xen/blkback: separate ring information out of struct xen_blkif
El 05/09/15 a les 14.39, Bob Liu ha escrit:
> Split per ring information to an new structure:xen_blkif_ring, so that one vbd
> device can associate with one or more rings/hardware queues.
>
> This patch is a preparation for supporting multi hardware queues/rings.
>
> Signed-off-by: Arianna Avanzini
> Signed-off-by: Bob Liu
> ---
> drivers/block/xen-blkback/blkback.c | 365
> ++-
> drivers/block/xen-blkback/common.h | 52 +++--
> drivers/block/xen-blkback/xenbus.c | 130 +++--
> 3 files changed, 295 insertions(+), 252 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/blkback.c
> b/drivers/block/xen-blkback/blkback.c
> index 954c002..fd02240 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -113,71 +113,71 @@ module_param(log_stats, int, 0644);
> /* Number of free pages to remove on each call to gnttab_free_pages */
> #define NUM_BATCH_FREE_PAGES 10
>
> -static inline int get_free_page(struct xen_blkif *blkif, struct page **page)
> +static inline int get_free_page(struct xen_blkif_ring *ring, struct page
> **page)
> {
> unsigned long flags;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> - if (list_empty(&blkif->free_pages)) {
> - BUG_ON(blkif->free_pages_num != 0);
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> + if (list_empty(&ring->free_pages)) {
I'm afraid the pool of free pages should be per-device, not per-ring.
> + BUG_ON(ring->free_pages_num != 0);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> return gnttab_alloc_pages(1, page);
> }
> - BUG_ON(blkif->free_pages_num == 0);
> - page[0] = list_first_entry(&blkif->free_pages, struct page, lru);
> + BUG_ON(ring->free_pages_num == 0);
> + page[0] = list_first_entry(&ring->free_pages, struct page, lru);
> list_del(&page[0]->lru);
> - blkif->free_pages_num--;
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + ring->free_pages_num--;
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
>
> return 0;
> }
>
> -static inline void put_free_pages(struct xen_blkif *blkif, struct page
> **page,
> +static inline void put_free_pages(struct xen_blkif_ring *ring, struct page
> **page,
>int num)
> {
> unsigned long flags;
> int i;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> for (i = 0; i < num; i++)
> - list_add(&page[i]->lru, &blkif->free_pages);
> - blkif->free_pages_num += num;
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + list_add(&page[i]->lru, &ring->free_pages);
> + ring->free_pages_num += num;
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> }
>
> -static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num)
> +static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num)
> {
> /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
> struct page *page[NUM_BATCH_FREE_PAGES];
> unsigned int num_pages = 0;
> unsigned long flags;
>
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> - while (blkif->free_pages_num > num) {
> - BUG_ON(list_empty(&blkif->free_pages));
> - page[num_pages] = list_first_entry(&blkif->free_pages,
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> + while (ring->free_pages_num > num) {
> + BUG_ON(list_empty(&ring->free_pages));
> + page[num_pages] = list_first_entry(&ring->free_pages,
> struct page, lru);
> list_del(&page[num_pages]->lru);
> - blkif->free_pages_num--;
> + ring->free_pages_num--;
> if (++num_pages == NUM_BATCH_FREE_PAGES) {
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> gnttab_free_pages(num_pages, page);
> - spin_lock_irqsave(&blkif->free_pages_lock, flags);
> + spin_lock_irqsave(&ring->free_pages_lock, flags);
> num_pages = 0;
> }
> }
> - spin_unlock_irqrestore(&blkif->free_pages_lock, flags);
> + spin_unlock_irqrestore(&ring->free_pages_lock, flags);
> if (num_pages != 0)
> gnttab_free_pages(num_pages, page);
> }
>
> #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
>
> -static int do_block_io_op(struct xen_blkif *blkif);
> -static int dispatch_rw_block_io(struct xen_blkif *blkif,
> +static int do_block_io_op(struct xen_blkif_ring *ring);
> +static i
