dma-mapping updates for Linux 2.6

- reduce the swiotlb buffer size on allocation failure
    (Alexey Kardashevskiy)
  - clean up passing of bogus GFP flags to the dma-coherent allocator
    (Christoph Hellwig)
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Merge tag 'dma-mapping-6.2-2022-12-13' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - reduce the swiotlb buffer size on allocation failure (Alexey
   Kardashevskiy)

 - clean up passing of bogus GFP flags to the dma-coherent allocator
   (Christoph Hellwig)

* tag 'dma-mapping-6.2-2022-12-13' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: reject __GFP_COMP in dma_alloc_attrs
  ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_*
  s390/ism: don't pass bogus GFP_ flags to dma_alloc_coherent
  cnic: don't pass bogus GFP_ flags to dma_alloc_coherent
  RDMA/qib: don't pass bogus GFP_ flags to dma_alloc_coherent
  RDMA/hfi1: don't pass bogus GFP_ flags to dma_alloc_coherent
  media: videobuf-dma-contig: use dma_mmap_coherent
  swiotlb: reduce the swiotlb buffer size on allocation failure

arch/arm/mm/dma-mapping.c

@@ -564,14 +564,6 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
 	if (mask < 0xffffffffULL)
 		gfp |= GFP_DMA;
 
-	/*
-	 * Following is a work-around (a.k.a. hack) to prevent pages
-	 * with __GFP_COMP being passed to split_page() which cannot
-	 * handle them.  The real problem is that this flag probably
-	 * should be 0 on ARM as it is not supported on this
-	 * platform; see CONFIG_HUGETLBFS.
-	 */
-	gfp &= ~(__GFP_COMP);
 	args.gfp = gfp;
 
 	*handle = DMA_MAPPING_ERROR;
@@ -1093,15 +1085,6 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
 		return __iommu_alloc_simple(dev, size, gfp, handle,
 					    coherent_flag, attrs);
 
-	/*
-	 * Following is a work-around (a.k.a. hack) to prevent pages
-	 * with __GFP_COMP being passed to split_page() which cannot
-	 * handle them.  The real problem is that this flag probably
-	 * should be 0 on ARM as it is not supported on this
-	 * platform; see CONFIG_HUGETLBFS.
-	 */
-	gfp &= ~(__GFP_COMP);
-
 	pages = __iommu_alloc_buffer(dev, size, gfp, attrs, coherent_flag);
 	if (!pages)
 		return NULL;

drivers/infiniband/hw/hfi1/init.c

@@ -1761,17 +1761,11 @@ int hfi1_create_rcvhdrq(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd)
 	unsigned amt;
 
 	if (!rcd->rcvhdrq) {
-		gfp_t gfp_flags;
-
 		amt = rcvhdrq_size(rcd);
 
-		if (rcd->ctxt < dd->first_dyn_alloc_ctxt || rcd->is_vnic)
-			gfp_flags = GFP_KERNEL;
-		else
-			gfp_flags = GFP_USER;
 		rcd->rcvhdrq = dma_alloc_coherent(&dd->pcidev->dev, amt,
 						  &rcd->rcvhdrq_dma,
-						  gfp_flags | __GFP_COMP);
+						  GFP_KERNEL);
 
 		if (!rcd->rcvhdrq) {
 			dd_dev_err(dd,
@@ -1785,7 +1779,7 @@ int hfi1_create_rcvhdrq(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd)
 			rcd->rcvhdrtail_kvaddr = dma_alloc_coherent(&dd->pcidev->dev,
 								    PAGE_SIZE,
 								    &rcd->rcvhdrqtailaddr_dma,
-								    gfp_flags);
+								    GFP_KERNEL);
 			if (!rcd->rcvhdrtail_kvaddr)
 				goto bail_free;
 		}
@@ -1821,19 +1815,10 @@ int hfi1_setup_eagerbufs(struct hfi1_ctxtdata *rcd)
 {
 	struct hfi1_devdata *dd = rcd->dd;
 	u32 max_entries, egrtop, alloced_bytes = 0;
-	gfp_t gfp_flags;
 	u16 order, idx = 0;
 	int ret = 0;
 	u16 round_mtu = roundup_pow_of_two(hfi1_max_mtu);
 
-	/*
-	 * GFP_USER, but without GFP_FS, so buffer cache can be
-	 * coalesced (we hope); otherwise, even at order 4,
-	 * heavy filesystem activity makes these fail, and we can
-	 * use compound pages.
-	 */
-	gfp_flags = __GFP_RECLAIM | __GFP_IO | __GFP_COMP;
-
 	/*
 	 * The minimum size of the eager buffers is a groups of MTU-sized
 	 * buffers.
@@ -1864,7 +1849,7 @@ int hfi1_setup_eagerbufs(struct hfi1_ctxtdata *rcd)
 			dma_alloc_coherent(&dd->pcidev->dev,
 					   rcd->egrbufs.rcvtid_size,
 					   &rcd->egrbufs.buffers[idx].dma,
-					   gfp_flags);
+					   GFP_KERNEL);
 		if (rcd->egrbufs.buffers[idx].addr) {
 			rcd->egrbufs.buffers[idx].len =
 				rcd->egrbufs.rcvtid_size;

drivers/infiniband/hw/qib/qib_iba6120.c

@@ -2075,7 +2075,7 @@ static void alloc_dummy_hdrq(struct qib_devdata *dd)
 	dd->cspec->dummy_hdrq = dma_alloc_coherent(&dd->pcidev->dev,
 					dd->rcd[0]->rcvhdrq_size,
 					&dd->cspec->dummy_hdrq_phys,
-					GFP_ATOMIC | __GFP_COMP);
+					GFP_ATOMIC);
 	if (!dd->cspec->dummy_hdrq) {
 		qib_devinfo(dd->pcidev, "Couldn't allocate dummy hdrq\n");
 		/* fallback to just 0'ing */

drivers/infiniband/hw/qib/qib_init.c

@@ -1546,18 +1546,14 @@ int qib_create_rcvhdrq(struct qib_devdata *dd, struct qib_ctxtdata *rcd)
 
 	if (!rcd->rcvhdrq) {
 		dma_addr_t phys_hdrqtail;
-		gfp_t gfp_flags;
 
 		amt = ALIGN(dd->rcvhdrcnt * dd->rcvhdrentsize *
 			    sizeof(u32), PAGE_SIZE);
-		gfp_flags = (rcd->ctxt >= dd->first_user_ctxt) ?
-			GFP_USER : GFP_KERNEL;
 
 		old_node_id = dev_to_node(&dd->pcidev->dev);
 		set_dev_node(&dd->pcidev->dev, rcd->node_id);
-		rcd->rcvhdrq = dma_alloc_coherent(
-			&dd->pcidev->dev, amt, &rcd->rcvhdrq_phys,
-			gfp_flags | __GFP_COMP);
+		rcd->rcvhdrq = dma_alloc_coherent(&dd->pcidev->dev, amt,
+				&rcd->rcvhdrq_phys, GFP_KERNEL);
 		set_dev_node(&dd->pcidev->dev, old_node_id);
 
 		if (!rcd->rcvhdrq) {
@@ -1577,7 +1573,7 @@ int qib_create_rcvhdrq(struct qib_devdata *dd, struct qib_ctxtdata *rcd)
 			set_dev_node(&dd->pcidev->dev, rcd->node_id);
 			rcd->rcvhdrtail_kvaddr = dma_alloc_coherent(
 				&dd->pcidev->dev, PAGE_SIZE, &phys_hdrqtail,
-				gfp_flags);
+				GFP_KERNEL);
 			set_dev_node(&dd->pcidev->dev, old_node_id);
 			if (!rcd->rcvhdrtail_kvaddr)
 				goto bail_free;
@@ -1621,17 +1617,8 @@ int qib_setup_eagerbufs(struct qib_ctxtdata *rcd)
 	struct qib_devdata *dd = rcd->dd;
 	unsigned e, egrcnt, egrperchunk, chunk, egrsize, egroff;
 	size_t size;
-	gfp_t gfp_flags;
 	int old_node_id;
 
-	/*
-	 * GFP_USER, but without GFP_FS, so buffer cache can be
-	 * coalesced (we hope); otherwise, even at order 4,
-	 * heavy filesystem activity makes these fail, and we can
-	 * use compound pages.
-	 */
-	gfp_flags = __GFP_RECLAIM | __GFP_IO | __GFP_COMP;
-
 	egrcnt = rcd->rcvegrcnt;
 	egroff = rcd->rcvegr_tid_base;
 	egrsize = dd->rcvegrbufsize;
@@ -1663,7 +1650,7 @@ int qib_setup_eagerbufs(struct qib_ctxtdata *rcd)
 		rcd->rcvegrbuf[e] =
 			dma_alloc_coherent(&dd->pcidev->dev, size,
 					   &rcd->rcvegrbuf_phys[e],
-					   gfp_flags);
+					   GFP_KERNEL);
 		set_dev_node(&dd->pcidev->dev, old_node_id);
 		if (!rcd->rcvegrbuf[e])
 			goto bail_rcvegrbuf_phys;

drivers/iommu/dma-iommu.c

@@ -744,9 +744,6 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
 	/* IOMMU can map any pages, so himem can also be used here */
 	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
 
-	/* It makes no sense to muck about with huge pages */
-	gfp &= ~__GFP_COMP;
-
 	while (count) {
 		struct page *page = NULL;
 		unsigned int order_size;

drivers/media/v4l2-core/videobuf-dma-contig.c

@@ -36,12 +36,11 @@ struct videobuf_dma_contig_memory {
 
 static int __videobuf_dc_alloc(struct device *dev,
 			       struct videobuf_dma_contig_memory *mem,
-			       unsigned long size, gfp_t flags)
+			       unsigned long size)
 {
 	mem->size = size;
-	mem->vaddr = dma_alloc_coherent(dev, mem->size,
-					&mem->dma_handle, flags);
-
+	mem->vaddr = dma_alloc_coherent(dev, mem->size, &mem->dma_handle,
+					GFP_KERNEL);
 	if (!mem->vaddr) {
 		dev_err(dev, "memory alloc size %ld failed\n", mem->size);
 		return -ENOMEM;
@@ -258,8 +257,7 @@ static int __videobuf_iolock(struct videobuf_queue *q,
 			return videobuf_dma_contig_user_get(mem, vb);
 
 		/* allocate memory for the read() method */
-		if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size),
-					GFP_KERNEL))
+		if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(vb->size)))
 			return -ENOMEM;
 		break;
 	case V4L2_MEMORY_OVERLAY:
@@ -295,22 +293,18 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 	BUG_ON(!mem);
 	MAGIC_CHECK(mem->magic, MAGIC_DC_MEM);
 
-	if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize),
-				GFP_KERNEL | __GFP_COMP))
+	if (__videobuf_dc_alloc(q->dev, mem, PAGE_ALIGN(buf->bsize)))
 		goto error;
 
-	/* Try to remap memory */
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
 	/* the "vm_pgoff" is just used in v4l2 to find the
 	 * corresponding buffer data structure which is allocated
 	 * earlier and it does not mean the offset from the physical
 	 * buffer start address as usual. So set it to 0 to pass
-	 * the sanity check in vm_iomap_memory().
+	 * the sanity check in dma_mmap_coherent().
 	 */
 	vma->vm_pgoff = 0;
-
-	retval = vm_iomap_memory(vma, mem->dma_handle, mem->size);
+	retval = dma_mmap_coherent(q->dev, vma, mem->vaddr, mem->dma_handle,
+				   mem->size);
 	if (retval) {
 		dev_err(q->dev, "mmap: remap failed with error %d. ",
 			retval);

drivers/net/ethernet/broadcom/cnic.c

@@ -1027,16 +1027,14 @@ static int __cnic_alloc_uio_rings(struct cnic_uio_dev *udev, int pages)
 
 	udev->l2_ring_size = pages * CNIC_PAGE_SIZE;
 	udev->l2_ring = dma_alloc_coherent(&udev->pdev->dev, udev->l2_ring_size,
-					   &udev->l2_ring_map,
-					   GFP_KERNEL | __GFP_COMP);
+					   &udev->l2_ring_map, GFP_KERNEL);
 	if (!udev->l2_ring)
 		return -ENOMEM;
 
 	udev->l2_buf_size = (cp->l2_rx_ring_size + 1) * cp->l2_single_buf_size;
 	udev->l2_buf_size = CNIC_PAGE_ALIGN(udev->l2_buf_size);
 	udev->l2_buf = dma_alloc_coherent(&udev->pdev->dev, udev->l2_buf_size,
-					  &udev->l2_buf_map,
-					  GFP_KERNEL | __GFP_COMP);
+					  &udev->l2_buf_map, GFP_KERNEL);
 	if (!udev->l2_buf) {
 		__cnic_free_uio_rings(udev);
 		return -ENOMEM;

drivers/s390/net/ism_drv.c

@@ -243,7 +243,8 @@ static int ism_alloc_dmb(struct ism_dev *ism, struct smcd_dmb *dmb)
 
 	dmb->cpu_addr = dma_alloc_coherent(&ism->pdev->dev, dmb->dmb_len,
 					   &dmb->dma_addr,
-					   GFP_KERNEL | __GFP_NOWARN | __GFP_NOMEMALLOC | __GFP_COMP | __GFP_NORETRY);
+					   GFP_KERNEL | __GFP_NOWARN |
+					   __GFP_NOMEMALLOC | __GFP_NORETRY);
 	if (!dmb->cpu_addr)
 		clear_bit(dmb->sba_idx, ism->sba_bitmap);
 

kernel/dma/mapping.c

@@ -498,6 +498,14 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 
 	WARN_ON_ONCE(!dev->coherent_dma_mask);
 
+	/*
+	 * DMA allocations can never be turned back into a page pointer, so
+	 * requesting compound pages doesn't make sense (and can't even be
+	 * supported at all by various backends).
+	 */
+	if (WARN_ON_ONCE(flag & __GFP_COMP))
+		return NULL;
+
 	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
 		return cpu_addr;
 

kernel/dma/swiotlb.c

@@ -300,6 +300,37 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
 	return;
 }
 
+static void *swiotlb_memblock_alloc(unsigned long nslabs, unsigned int flags,
+		int (*remap)(void *tlb, unsigned long nslabs))
+{
+	size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT);
+	void *tlb;
+
+	/*
+	 * By default allocate the bounce buffer memory from low memory, but
+	 * allow to pick a location everywhere for hypervisors with guest
+	 * memory encryption.
+	 */
+	if (flags & SWIOTLB_ANY)
+		tlb = memblock_alloc(bytes, PAGE_SIZE);
+	else
+		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
+
+	if (!tlb) {
+		pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
+			__func__, bytes);
+		return NULL;
+	}
+
+	if (remap && remap(tlb, nslabs) < 0) {
+		memblock_free(tlb, PAGE_ALIGN(bytes));
+		pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes);
+		return NULL;
+	}
+
+	return tlb;
+}
+
 /*
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
@@ -310,7 +341,6 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
 	struct io_tlb_mem *mem = &io_tlb_default_mem;
 	unsigned long nslabs;
 	size_t alloc_size;
-	size_t bytes;
 	void *tlb;
 
 	if (!addressing_limit && !swiotlb_force_bounce)
@@ -326,31 +356,16 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
 		swiotlb_adjust_nareas(num_possible_cpus());
 
 	nslabs = default_nslabs;
-	/*
-	 * By default allocate the bounce buffer memory from low memory, but
-	 * allow to pick a location everywhere for hypervisors with guest
-	 * memory encryption.
-	 */
-retry:
-	bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT);
-	if (flags & SWIOTLB_ANY)
-		tlb = memblock_alloc(bytes, PAGE_SIZE);
-	else
-		tlb = memblock_alloc_low(bytes, PAGE_SIZE);
-	if (!tlb) {
-		pr_warn("%s: failed to allocate tlb structure\n", __func__);
-		return;
+	while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) {
+		if (nslabs <= IO_TLB_MIN_SLABS)
+			return;
+		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
 	}
 
-	if (remap && remap(tlb, nslabs) < 0) {
-		memblock_free(tlb, PAGE_ALIGN(bytes));
-
-		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
-		if (nslabs >= IO_TLB_MIN_SLABS)
-			goto retry;
-
-		pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes);
-		return;
+	if (default_nslabs != nslabs) {
+		pr_info("SWIOTLB bounce buffer size adjusted %lu -> %lu slabs",
+			default_nslabs, nslabs);
+		default_nslabs = nslabs;
 	}
 
 	alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));

sound/core/memalloc.c

@@ -21,7 +21,6 @@
 
 #define DEFAULT_GFP \
 	(GFP_KERNEL | \
-	 __GFP_COMP |    /* compound page lets parts be mapped */ \
 	 __GFP_RETRY_MAYFAIL | /* don't trigger OOM-killer */ \
 	 __GFP_NOWARN)   /* no stack trace print - this call is non-critical */
 
@@ -543,7 +542,7 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
 	void *p;
 
 	sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
-				      DEFAULT_GFP, 0);
+				      DEFAULT_GFP | __GFP_COMP, 0);
 #ifdef CONFIG_SND_DMA_SGBUF
 	if (!sgt && !get_dma_ops(dmab->dev.dev)) {
 		if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
@@ -811,7 +810,7 @@ static void *snd_dma_noncoherent_alloc(struct snd_dma_buffer *dmab, size_t size)
 	void *p;
 
 	p = dma_alloc_noncoherent(dmab->dev.dev, size, &dmab->addr,
-				  dmab->dev.dir, DEFAULT_GFP);
+				  dmab->dev.dir, DEFAULT_GFP | __GFP_COMP);
 	if (p)
 		dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->addr);
 	return p;