iommu/iova: Squash entry_dtor abstraction

All flush queues are driven by iommu-dma now, so there is no need to
abstract entry_dtor or its data any more. Squash the now-canonical
implementation directly into the IOVA code to get it out of the way.
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/2260f8de00ab5e0f9d2a1cf8978e6ae7cd4f182c.1639753638.git.robin.murphy@arm.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/dma-iommu.c

@@ -64,18 +64,6 @@ static int __init iommu_dma_forcedac_setup(char *str)
 }
 early_param("iommu.forcedac", iommu_dma_forcedac_setup);
 
-static void iommu_dma_entry_dtor(unsigned long data)
-{
-	struct page *freelist = (struct page *)data;
-
-	while (freelist) {
-		unsigned long p = (unsigned long)page_address(freelist);
-
-		freelist = freelist->freelist;
-		free_page(p);
-	}
-}
-
 static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
 {
 	if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
@@ -324,8 +312,7 @@ int iommu_dma_init_fq(struct iommu_domain *domain)
 	if (cookie->fq_domain)
 		return 0;
 
-	ret = init_iova_flush_queue(&cookie->iovad, iommu_dma_flush_iotlb_all,
-				    iommu_dma_entry_dtor);
+	ret = init_iova_flush_queue(&cookie->iovad, iommu_dma_flush_iotlb_all);
 	if (ret) {
 		pr_warn("iova flush queue initialization failed\n");
 		return ret;
@@ -471,7 +458,7 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
 	else if (gather && gather->queued)
 		queue_iova(iovad, iova_pfn(iovad, iova),
 				size >> iova_shift(iovad),
-				(unsigned long)gather->freelist);
+				gather->freelist);
 	else
 		free_iova_fast(iovad, iova_pfn(iovad, iova),
 				size >> iova_shift(iovad));

drivers/iommu/iova.c

@@ -91,11 +91,9 @@ static void free_iova_flush_queue(struct iova_domain *iovad)
 
 	iovad->fq         = NULL;
 	iovad->flush_cb   = NULL;
-	iovad->entry_dtor = NULL;
 }
 
-int init_iova_flush_queue(struct iova_domain *iovad,
-			  iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)
+int init_iova_flush_queue(struct iova_domain *iovad, iova_flush_cb flush_cb)
 {
 	struct iova_fq __percpu *queue;
 	int cpu;
@@ -108,7 +106,6 @@ int init_iova_flush_queue(struct iova_domain *iovad,
 		return -ENOMEM;
 
 	iovad->flush_cb   = flush_cb;
-	iovad->entry_dtor = entry_dtor;
 
 	for_each_possible_cpu(cpu) {
 		struct iova_fq *fq;
@@ -547,6 +544,16 @@ free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
 }
 EXPORT_SYMBOL_GPL(free_iova_fast);
 
+static void fq_entry_dtor(struct page *freelist)
+{
+	while (freelist) {
+		unsigned long p = (unsigned long)page_address(freelist);
+
+		freelist = freelist->freelist;
+		free_page(p);
+	}
+}
+
 #define fq_ring_for_each(i, fq) \
 	for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) % IOVA_FQ_SIZE)
 
@@ -579,9 +586,7 @@ static void fq_ring_free(struct iova_domain *iovad, struct iova_fq *fq)
 		if (fq->entries[idx].counter >= counter)
 			break;
 
-		if (iovad->entry_dtor)
-			iovad->entry_dtor(fq->entries[idx].data);
-
+		fq_entry_dtor(fq->entries[idx].freelist);
 		free_iova_fast(iovad,
 			       fq->entries[idx].iova_pfn,
 			       fq->entries[idx].pages);
@@ -606,15 +611,12 @@ static void fq_destroy_all_entries(struct iova_domain *iovad)
 	 * bother to free iovas, just call the entry_dtor on all remaining
 	 * entries.
 	 */
-	if (!iovad->entry_dtor)
-		return;
-
 	for_each_possible_cpu(cpu) {
 		struct iova_fq *fq = per_cpu_ptr(iovad->fq, cpu);
 		int idx;
 
 		fq_ring_for_each(idx, fq)
-			iovad->entry_dtor(fq->entries[idx].data);
+			fq_entry_dtor(fq->entries[idx].freelist);
 	}
 }
 
@@ -639,7 +641,7 @@ static void fq_flush_timeout(struct timer_list *t)
 
 void queue_iova(struct iova_domain *iovad,
 		unsigned long pfn, unsigned long pages,
-		unsigned long data)
+		struct page *freelist)
 {
 	struct iova_fq *fq;
 	unsigned long flags;
@@ -673,7 +675,7 @@ void queue_iova(struct iova_domain *iovad,
 
 	fq->entries[idx].iova_pfn = pfn;
 	fq->entries[idx].pages    = pages;
-	fq->entries[idx].data     = data;
+	fq->entries[idx].freelist = freelist;
 	fq->entries[idx].counter  = atomic64_read(&iovad->fq_flush_start_cnt);
 
 	spin_unlock_irqrestore(&fq->lock, flags);

include/linux/iova.h

@@ -40,9 +40,6 @@ struct iova_domain;
 /* Call-Back from IOVA code into IOMMU drivers */
 typedef void (* iova_flush_cb)(struct iova_domain *domain);
 
-/* Destructor for per-entry data */
-typedef void (* iova_entry_dtor)(unsigned long data);
-
 /* Number of entries per Flush Queue */
 #define IOVA_FQ_SIZE	256
 
@@ -53,7 +50,7 @@ typedef void (* iova_entry_dtor)(unsigned long data);
 struct iova_fq_entry {
 	unsigned long iova_pfn;
 	unsigned long pages;
-	unsigned long data;
+	struct page *freelist;
 	u64 counter; /* Flush counter when this entrie was added */
 };
 
@@ -88,9 +85,6 @@ struct iova_domain {
 	iova_flush_cb	flush_cb;	/* Call-Back function to flush IOMMU
 					   TLBs */
 
-	iova_entry_dtor entry_dtor;	/* IOMMU driver specific destructor for
-					   iova entry */
-
 	struct timer_list fq_timer;		/* Timer to regularily empty the
 						   flush-queues */
 	atomic_t fq_timer_on;			/* 1 when timer is active, 0
@@ -146,15 +140,14 @@ void free_iova_fast(struct iova_domain *iovad, unsigned long pfn,
 		    unsigned long size);
 void queue_iova(struct iova_domain *iovad,
 		unsigned long pfn, unsigned long pages,
-		unsigned long data);
+		struct page *freelist);
 unsigned long alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
 			      unsigned long limit_pfn, bool flush_rcache);
 struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo,
 	unsigned long pfn_hi);
 void init_iova_domain(struct iova_domain *iovad, unsigned long granule,
 	unsigned long start_pfn);
-int init_iova_flush_queue(struct iova_domain *iovad,
-			  iova_flush_cb flush_cb, iova_entry_dtor entry_dtor);
+int init_iova_flush_queue(struct iova_domain *iovad, iova_flush_cb flush_cb);
 struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
 void put_iova_domain(struct iova_domain *iovad);
 #else
@@ -189,12 +182,6 @@ static inline void free_iova_fast(struct iova_domain *iovad,
 {
 }
 
-static inline void queue_iova(struct iova_domain *iovad,
-			      unsigned long pfn, unsigned long pages,
-			      unsigned long data)
-{
-}
-
 static inline unsigned long alloc_iova_fast(struct iova_domain *iovad,
 					    unsigned long size,
 					    unsigned long limit_pfn,
@@ -216,13 +203,6 @@ static inline void init_iova_domain(struct iova_domain *iovad,
 {
 }
 
-static inline int init_iova_flush_queue(struct iova_domain *iovad,
-					iova_flush_cb flush_cb,
-					iova_entry_dtor entry_dtor)
-{
-	return -ENODEV;
-}
-
 static inline struct iova *find_iova(struct iova_domain *iovad,
 				     unsigned long pfn)
 {