修改内核路径

hc

2024-05-14 bedbef8ad3e75a304af6361af235302bcc61d06b

 kernel/drivers/block/xen-blkback/blkback.c
..
..
@@ -62,8 +62,8 @@
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  * IO workloads.
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  */
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64
 
65
-static int xen_blkif_max_buffer_pages = 1024;
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-module_param_named(max_buffer_pages, xen_blkif_max_buffer_pages, int, 0644);
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+static int max_buffer_pages = 1024;
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+module_param_named(max_buffer_pages, max_buffer_pages, int, 0644);
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 MODULE_PARM_DESC(max_buffer_pages,
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 "Maximum number of free pages to keep in each block backend buffer");
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69
 
..
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@@ -78,8 +78,8 @@
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  * algorithm.
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  */
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81
-static int xen_blkif_max_pgrants = 1056;
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-module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644);
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+static int max_pgrants = 1056;
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+module_param_named(max_persistent_grants, max_pgrants, int, 0644);
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 MODULE_PARM_DESC(max_persistent_grants,
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                  "Maximum number of grants to map persistently");
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85
 
..
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@@ -88,8 +88,8 @@
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  * use. The time is in seconds, 0 means indefinitely long.
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  */
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90
 
91
-static unsigned int xen_blkif_pgrant_timeout = 60;
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-module_param_named(persistent_grant_unused_seconds, xen_blkif_pgrant_timeout,
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+static unsigned int pgrant_timeout = 60;
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+module_param_named(persistent_grant_unused_seconds, pgrant_timeout,
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 		   uint, 0644);
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 MODULE_PARM_DESC(persistent_grant_unused_seconds,
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 		 "Time in seconds an unused persistent grant is allowed to "
..
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@@ -132,72 +132,10 @@
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132
 
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 #define BLKBACK_INVALID_HANDLE (~0)
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134
 
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-/* Number of free pages to remove on each call to gnttab_free_pages */
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-#define NUM_BATCH_FREE_PAGES 10
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-
138
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 static inline bool persistent_gnt_timeout(struct persistent_gnt *persistent_gnt)
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136
 {
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-	return xen_blkif_pgrant_timeout &&
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-	       (jiffies - persistent_gnt->last_used >=
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-		HZ * xen_blkif_pgrant_timeout);
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-}
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-
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-static inline int get_free_page(struct xen_blkif_ring *ring, struct page **page)
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-{
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-	unsigned long flags;
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-
149
-	spin_lock_irqsave(&ring->free_pages_lock, flags);
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-	if (list_empty(&ring->free_pages)) {
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-		BUG_ON(ring->free_pages_num != 0);
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-		spin_unlock_irqrestore(&ring->free_pages_lock, flags);
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-		return gnttab_alloc_pages(1, page);
154
-	}
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-	BUG_ON(ring->free_pages_num == 0);
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-	page[0] = list_first_entry(&ring->free_pages, struct page, lru);
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-	list_del(&page[0]->lru);
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-	ring->free_pages_num--;
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-	spin_unlock_irqrestore(&ring->free_pages_lock, flags);
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-
161
-	return 0;
162
-}
163
-
164
-static inline void put_free_pages(struct xen_blkif_ring *ring, struct page **page,
165
-                                  int num)
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-{
167
-	unsigned long flags;
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-	int i;
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-
170
-	spin_lock_irqsave(&ring->free_pages_lock, flags);
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-	for (i = 0; i < num; i++)
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-		list_add(&page[i]->lru, &ring->free_pages);
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-	ring->free_pages_num += num;
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-	spin_unlock_irqrestore(&ring->free_pages_lock, flags);
175
-}
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-
177
-static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num)
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-{
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-	/* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
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-	struct page *page[NUM_BATCH_FREE_PAGES];
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-	unsigned int num_pages = 0;
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-	unsigned long flags;
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-
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-	spin_lock_irqsave(&ring->free_pages_lock, flags);
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-	while (ring->free_pages_num > num) {
186
-		BUG_ON(list_empty(&ring->free_pages));
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-		page[num_pages] = list_first_entry(&ring->free_pages,
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-		                                   struct page, lru);
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-		list_del(&page[num_pages]->lru);
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-		ring->free_pages_num--;
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-		if (++num_pages == NUM_BATCH_FREE_PAGES) {
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-			spin_unlock_irqrestore(&ring->free_pages_lock, flags);
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-			gnttab_free_pages(num_pages, page);
194
-			spin_lock_irqsave(&ring->free_pages_lock, flags);
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-			num_pages = 0;
196
-		}
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-	}
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-	spin_unlock_irqrestore(&ring->free_pages_lock, flags);
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-	if (num_pages != 0)
200
-		gnttab_free_pages(num_pages, page);
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+	return pgrant_timeout && (jiffies - persistent_gnt->last_used >=
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+			HZ * pgrant_timeout);
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139
 }
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140
 
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 #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
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@@ -234,7 +172,7 @@
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 	struct persistent_gnt *this;
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 	struct xen_blkif *blkif = ring->blkif;
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174
 
237
-	if (ring->persistent_gnt_c >= xen_blkif_max_pgrants) {
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+	if (ring->persistent_gnt_c >= max_pgrants) {
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176
 		if (!blkif->vbd.overflow_max_grants)
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 			blkif->vbd.overflow_max_grants = 1;
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 		return -EBUSY;
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@@ -332,7 +270,8 @@
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 			unmap_data.count = segs_to_unmap;
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 			BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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-			put_free_pages(ring, pages, segs_to_unmap);
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+			gnttab_page_cache_put(&ring->free_pages, pages,
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+					      segs_to_unmap);
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 			segs_to_unmap = 0;
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 		}
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..
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@@ -372,7 +311,8 @@
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 		if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
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 			unmap_data.count = segs_to_unmap;
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 			BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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-			put_free_pages(ring, pages, segs_to_unmap);
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+			gnttab_page_cache_put(&ring->free_pages, pages,
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+					      segs_to_unmap);
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 			segs_to_unmap = 0;
377
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 		}
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 		kfree(persistent_gnt);
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@@ -380,7 +320,7 @@
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 	if (segs_to_unmap > 0) {
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 		unmap_data.count = segs_to_unmap;
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 		BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
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-		put_free_pages(ring, pages, segs_to_unmap);
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+		gnttab_page_cache_put(&ring->free_pages, pages, segs_to_unmap);
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 	}
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 }
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..
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@@ -397,14 +337,13 @@
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 		goto out;
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 	}
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339
 
400
-	if (ring->persistent_gnt_c < xen_blkif_max_pgrants ||
401
-	    (ring->persistent_gnt_c == xen_blkif_max_pgrants &&
340
+	if (ring->persistent_gnt_c < max_pgrants ||
341
+	    (ring->persistent_gnt_c == max_pgrants &&
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 	    !ring->blkif->vbd.overflow_max_grants)) {
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 		num_clean = 0;
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 	} else {
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-		num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN;
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-		num_clean = ring->persistent_gnt_c - xen_blkif_max_pgrants +
407
-			    num_clean;
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+		num_clean = (max_pgrants / 100) * LRU_PERCENT_CLEAN;
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+		num_clean = ring->persistent_gnt_c - max_pgrants + num_clean;
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 		num_clean = min(ring->persistent_gnt_c, num_clean);
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 		pr_debug("Going to purge at least %u persistent grants\n",
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 			 num_clean);
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@@ -599,8 +538,7 @@
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 		 current->comm, ring->st_oo_req,
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 		 ring->st_rd_req, ring->st_wr_req,
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 		 ring->st_f_req, ring->st_ds_req,
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-		 ring->persistent_gnt_c,
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-		 xen_blkif_max_pgrants);
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+		 ring->persistent_gnt_c, max_pgrants);
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 	ring->st_print = jiffies + msecs_to_jiffies(10 * 1000);
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 	ring->st_rd_req = 0;
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 	ring->st_wr_req = 0;
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@@ -665,8 +603,12 @@
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 			ring->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL);
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 		}
667
605
 
668
-		/* Shrink if we have more than xen_blkif_max_buffer_pages */
669
-		shrink_free_pagepool(ring, xen_blkif_max_buffer_pages);
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+		/* Shrink the free pages pool if it is too large. */
607
+		if (time_before(jiffies, blkif->buffer_squeeze_end))
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+			gnttab_page_cache_shrink(&ring->free_pages, 0);
609
+		else
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+			gnttab_page_cache_shrink(&ring->free_pages,
611
+						 max_buffer_pages);
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612
 
671
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 		if (log_stats && time_after(jiffies, ring->st_print))
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 			print_stats(ring);
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@@ -697,7 +639,7 @@
697
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 	ring->persistent_gnt_c = 0;
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640
 
699
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 	/* Since we are shutting down remove all pages from the buffer */
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-	shrink_free_pagepool(ring, 0 /* All */);
642
+	gnttab_page_cache_shrink(&ring->free_pages, 0 /* All */);
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 }
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644
 
703
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 static unsigned int xen_blkbk_unmap_prepare(
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@@ -736,7 +678,7 @@
736
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 	   but is this the best way to deal with this? */
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 	BUG_ON(result);
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739
-	put_free_pages(ring, data->pages, data->count);
681
+	gnttab_page_cache_put(&ring->free_pages, data->pages, data->count);
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 	make_response(ring, pending_req->id,
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 		      pending_req->operation, pending_req->status);
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 	free_req(ring, pending_req);
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@@ -803,7 +745,8 @@
803
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 		if (invcount) {
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746
 			ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
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747
 			BUG_ON(ret);
806
-			put_free_pages(ring, unmap_pages, invcount);
748
+			gnttab_page_cache_put(&ring->free_pages, unmap_pages,
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+					      invcount);
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 		}
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 		pages += batch;
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 		num -= batch;
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@@ -850,8 +793,11 @@
850
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 			pages[i]->page = persistent_gnt->page;
851
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 			pages[i]->persistent_gnt = persistent_gnt;
852
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 		} else {
853
-			if (get_free_page(ring, &pages[i]->page)) {
854
-				put_free_pages(ring, pages_to_gnt, segs_to_map);
796
+			if (gnttab_page_cache_get(&ring->free_pages,
797
+						  &pages[i]->page)) {
798
+				gnttab_page_cache_put(&ring->free_pages,
799
+						      pages_to_gnt,
800
+						      segs_to_map);
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801
 				ret = -ENOMEM;
856
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 				goto out;
857
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 			}
..
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@@ -884,7 +830,8 @@
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 			BUG_ON(new_map_idx >= segs_to_map);
885
831
 			if (unlikely(map[new_map_idx].status != 0)) {
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832
 				pr_debug("invalid buffer -- could not remap it\n");
887
-				put_free_pages(ring, &pages[seg_idx]->page, 1);
833
+				gnttab_page_cache_put(&ring->free_pages,
834
+						      &pages[seg_idx]->page, 1);
888
835
 				pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE;
889
836
 				ret |= !ret;
890
837
 				goto next;
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@@ -894,7 +841,7 @@
894
841
 			continue;
895
842
 		}
896
843
 		if (use_persistent_gnts &&
897
-		    ring->persistent_gnt_c < xen_blkif_max_pgrants) {
844
+		    ring->persistent_gnt_c < max_pgrants) {
898
845
 			/*
899
846
 			 * We are using persistent grants, the grant is
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 			 * not mapped but we might have room for it.
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@@ -921,7 +868,7 @@
921
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 			pages[seg_idx]->persistent_gnt = persistent_gnt;
922
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 			pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n",
923
870
 				 persistent_gnt->gnt, ring->persistent_gnt_c,
924
-				 xen_blkif_max_pgrants);
871
+				 max_pgrants);
925
872
 			goto next;
926
873
 		}
927
874
 		if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) {
..
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@@ -1274,7 +1221,7 @@
1274
1221
 		break;
1275
1222
 	case BLKIF_OP_WRITE_BARRIER:
1276
1223
 		drain = true;
1277
-		/* fall through */
1224
+		fallthrough;
1278
1225
 	case BLKIF_OP_FLUSH_DISKCACHE:
1279
1226
 		ring->st_f_req++;
1280
1227
 		operation = REQ_OP_WRITE;
..
..
@@ -1520,5 +1467,13 @@
1520
1467
 
1521
1468
 module_init(xen_blkif_init);
1522
1469
 
1470
+static void __exit xen_blkif_fini(void)
1471
+{
1472
+	xen_blkif_xenbus_fini();
1473
+	xen_blkif_interface_fini();
1474
+}
1475
+
1476
+module_exit(xen_blkif_fini);
1477
+
1523
1478
 MODULE_LICENSE("Dual BSD/GPL");
1524
1479
 MODULE_ALIAS("xen-backend:vbd");