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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Jianxiong Gao <jxgao@google.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH 5.10 17/29] swiotlb: refactor swiotlb_tbl_map_single
Date: Wed,  5 May 2021 14:05:20 +0200	[thread overview]
Message-ID: <20210505112326.768975426@linuxfoundation.org> (raw)
In-Reply-To: <20210505112326.195493232@linuxfoundation.org>

From: Jianxiong Gao <jxgao@google.com>

commit: 26a7e094783d482f3e125f09945a5bb1d867b2e6

Split out a bunch of a self-contained helpers to make the function easier
to follow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jianxiong Gao <jxgao@google.com>
Tested-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/dma/swiotlb.c |  179 +++++++++++++++++++++++++--------------------------
 1 file changed, 89 insertions(+), 90 deletions(-)

--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -452,134 +452,133 @@ static void swiotlb_bounce(phys_addr_t o
 	}
 }
 
-phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
-		size_t mapping_size, size_t alloc_size,
-		enum dma_data_direction dir, unsigned long attrs)
-{
-	dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, io_tlb_start);
-	unsigned long flags;
-	phys_addr_t tlb_addr;
-	unsigned int nslots, stride, index, wrap;
-	int i;
-	unsigned long mask;
-	unsigned long offset_slots;
-	unsigned long max_slots;
-	unsigned long tmp_io_tlb_used;
+#define slot_addr(start, idx)	((start) + ((idx) << IO_TLB_SHIFT))
 
-	if (no_iotlb_memory)
-		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
-
-	if (mem_encrypt_active())
-		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
-
-	if (mapping_size > alloc_size) {
-		dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
-			      mapping_size, alloc_size);
-		return (phys_addr_t)DMA_MAPPING_ERROR;
-	}
-
-	mask = dma_get_seg_boundary(hwdev);
+/*
+ * Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
+ */
+static inline unsigned long get_max_slots(unsigned long boundary_mask)
+{
+	if (boundary_mask == ~0UL)
+		return 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
+	return nr_slots(boundary_mask + 1);
+}
 
-	tbl_dma_addr &= mask;
+static unsigned int wrap_index(unsigned int index)
+{
+	if (index >= io_tlb_nslabs)
+		return 0;
+	return index;
+}
 
-	offset_slots = nr_slots(tbl_dma_addr);
+/*
+ * Find a suitable number of IO TLB entries size that will fit this request and
+ * allocate a buffer from that IO TLB pool.
+ */
+static int find_slots(struct device *dev, size_t alloc_size)
+{
+	unsigned long boundary_mask = dma_get_seg_boundary(dev);
+	dma_addr_t tbl_dma_addr =
+		phys_to_dma_unencrypted(dev, io_tlb_start) & boundary_mask;
+	unsigned long max_slots = get_max_slots(boundary_mask);
+	unsigned int nslots = nr_slots(alloc_size), stride = 1;
+	unsigned int index, wrap, count = 0, i;
+	unsigned long flags;
 
-	/*
-	 * Carefully handle integer overflow which can occur when mask == ~0UL.
-	 */
-	max_slots = mask + 1
-		    ? nr_slots(mask + 1)
-		    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
+	BUG_ON(!nslots);
 
 	/*
 	 * For mappings greater than or equal to a page, we limit the stride
 	 * (and hence alignment) to a page size.
 	 */
-	nslots = nr_slots(alloc_size);
 	if (alloc_size >= PAGE_SIZE)
-		stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
-	else
-		stride = 1;
-
-	BUG_ON(!nslots);
+		stride <<= (PAGE_SHIFT - IO_TLB_SHIFT);
 
-	/*
-	 * Find suitable number of IO TLB entries size that will fit this
-	 * request and allocate a buffer from that IO TLB pool.
-	 */
 	spin_lock_irqsave(&io_tlb_lock, flags);
-
 	if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
 		goto not_found;
 
-	index = ALIGN(io_tlb_index, stride);
-	if (index >= io_tlb_nslabs)
-		index = 0;
-	wrap = index;
-
+	index = wrap = wrap_index(ALIGN(io_tlb_index, stride));
 	do {
-		while (iommu_is_span_boundary(index, nslots, offset_slots,
-					      max_slots)) {
-			index += stride;
-			if (index >= io_tlb_nslabs)
-				index = 0;
-			if (index == wrap)
-				goto not_found;
-		}
-
 		/*
 		 * If we find a slot that indicates we have 'nslots' number of
 		 * contiguous buffers, we allocate the buffers from that slot
 		 * and mark the entries as '0' indicating unavailable.
 		 */
-		if (io_tlb_list[index] >= nslots) {
-			int count = 0;
-
-			for (i = index; i < (int) (index + nslots); i++)
-				io_tlb_list[i] = 0;
-			for (i = index - 1;
-			     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
-			     io_tlb_list[i]; i--)
-				io_tlb_list[i] = ++count;
-			tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
-
-			/*
-			 * Update the indices to avoid searching in the next
-			 * round.
-			 */
-			io_tlb_index = ((index + nslots) < io_tlb_nslabs
-					? (index + nslots) : 0);
-
-			goto found;
+		if (!iommu_is_span_boundary(index, nslots,
+					    nr_slots(tbl_dma_addr),
+					    max_slots)) {
+			if (io_tlb_list[index] >= nslots)
+				goto found;
 		}
-		index += stride;
-		if (index >= io_tlb_nslabs)
-			index = 0;
+		index = wrap_index(index + stride);
 	} while (index != wrap);
 
 not_found:
-	tmp_io_tlb_used = io_tlb_used;
-
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
-	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
-		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
-			 alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
-	return (phys_addr_t)DMA_MAPPING_ERROR;
+	return -1;
+
 found:
+	for (i = index; i < index + nslots; i++)
+		io_tlb_list[i] = 0;
+	for (i = index - 1;
+	     io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
+	     io_tlb_list[i]; i--)
+		io_tlb_list[i] = ++count;
+
+	/*
+	 * Update the indices to avoid searching in the next round.
+	 */
+	if (index + nslots < io_tlb_nslabs)
+		io_tlb_index = index + nslots;
+	else
+		io_tlb_index = 0;
 	io_tlb_used += nslots;
+
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
+	return index;
+}
+
+phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
+		size_t mapping_size, size_t alloc_size,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	unsigned int index, i;
+	phys_addr_t tlb_addr;
+
+	if (no_iotlb_memory)
+		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+
+	if (mem_encrypt_active())
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+
+	if (mapping_size > alloc_size) {
+		dev_warn_once(dev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+			      mapping_size, alloc_size);
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
+
+	index = find_slots(dev, alloc_size);
+	if (index == -1) {
+		if (!(attrs & DMA_ATTR_NO_WARN))
+			dev_warn_ratelimited(dev,
+	"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
+				 alloc_size, io_tlb_nslabs, io_tlb_used);
+		return (phys_addr_t)DMA_MAPPING_ERROR;
+	}
 
 	/*
 	 * Save away the mapping from the original address to the DMA address.
 	 * This is needed when we sync the memory.  Then we sync the buffer if
 	 * needed.
 	 */
-	for (i = 0; i < nslots; i++)
-		io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
+	for (i = 0; i < nr_slots(alloc_size); i++)
+		io_tlb_orig_addr[index + i] = slot_addr(orig_addr, i);
+
+	tlb_addr = slot_addr(io_tlb_start, index);
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
 	    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
 		swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
-
 	return tlb_addr;
 }
 



  parent reply	other threads:[~2021-05-05 12:07 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-05 12:05 [PATCH 5.10 00/29] 5.10.35-rc1 review Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 01/29] mips: Do not include hi and lo in clobber list for R6 Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 02/29] netfilter: conntrack: Make global sysctls readonly in non-init netns Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 03/29] net: usb: ax88179_178a: initialize local variables before use Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 04/29] igb: Enable RSS for Intel I211 Ethernet Controller Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 05/29] bpf: Fix masking negation logic upon negative dst register Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 06/29] bpf: Fix leakage of uninitialized bpf stack under speculation Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 07/29] net: qrtr: Avoid potential use after free in MHI send Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 08/29] perf data: Fix error return code in perf_data__create_dir() Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 09/29] capabilities: require CAP_SETFCAP to map uid 0 Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 10/29] perf ftrace: Fix access to pid in array when setting a pid filter Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 11/29] tools/cgroup/slabinfo.py: updated to work on current kernel Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 12/29] driver core: add a min_align_mask field to struct device_dma_parameters Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 13/29] swiotlb: add a IO_TLB_SIZE define Greg Kroah-Hartman
2021-05-05 20:45   ` Yet another way to mark upstream commits was " Pavel Machek
2021-05-05 12:05 ` [PATCH 5.10 14/29] swiotlb: factor out an io_tlb_offset helper Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 15/29] swiotlb: factor out a nr_slots helper Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 16/29] swiotlb: clean up swiotlb_tbl_unmap_single Greg Kroah-Hartman
2021-05-05 12:05 ` Greg Kroah-Hartman [this message]
2021-05-05 12:05 ` [PATCH 5.10 18/29] swiotlb: dont modify orig_addr in swiotlb_tbl_sync_single Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 19/29] swiotlb: respect min_align_mask Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 20/29] nvme-pci: set min_align_mask Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 21/29] ovl: fix leaked dentry Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 22/29] ovl: allow upperdir inside lowerdir Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 23/29] ALSA: usb-audio: Add MIDI quirk for Vox ToneLab EX Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 24/29] USB: Add LPM quirk for Lenovo ThinkPad USB-C Dock Gen2 Ethernet Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 25/29] USB: Add reset-resume quirk for WD19s Realtek Hub Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 26/29] ASoC: ak4458: Add MODULE_DEVICE_TABLE Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 27/29] ASoC: ak5558: " Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 28/29] platform/x86: thinkpad_acpi: Correct thermal sensor allocation Greg Kroah-Hartman
2021-05-05 12:05 ` [PATCH 5.10 29/29] perf/core: Fix unconditional security_locked_down() call Greg Kroah-Hartman
2021-05-05 15:04 ` [PATCH 5.10 00/29] 5.10.35-rc1 review Patrick Mccormick
2021-05-05 19:30 ` Florian Fainelli
2021-05-05 20:19 ` Fox Chen
2021-05-05 21:04 ` Shuah Khan
2021-05-06  1:50 ` Guenter Roeck
2021-05-06  2:52 ` Samuel Zou
2021-05-06  7:46 ` Naresh Kamboju
2021-05-06  8:57 ` Pavel Machek
2021-05-06 10:07 ` Sudip Mukherjee

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