sparc: Make sparc64 use scalable lib/iommu-common.c functions

In iperf experiments running linux as the Tx side (TCP client) with
10 threads results in a severe performance drop when TSO is disabled,
indicating a weakness in the software that can be avoided by using
the scalable IOMMU arena DMA allocation.

Baseline numbers before this patch:
   with default settings (TSO enabled) :    9-9.5 Gbps
   Disable TSO using ethtool- drops badly:  2-3 Gbps.

After this patch, iperf client with 10 threads, can give a
throughput of at least 8.5 Gbps, even when TSO is disabled.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 129 deletions

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index bfa4d0c2df42..5320689c06e9 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -13,6 +13,7 @@
 #include <linux/errno.h>
 #include <linux/iommu-helper.h>
 #include <linux/bitmap.h>
+#include <linux/iommu-common.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -45,8 +46,9 @@
                                "i" (ASI_PHYS_BYPASS_EC_E))
 
 /* Must be invoked under the IOMMU lock. */
-static void iommu_flushall(struct iommu *iommu)
+static void iommu_flushall(struct iommu_map_table *iommu_map_table)
 {
+        struct iommu *iommu = container_of(iommu_map_table, struct iommu, tbl);
         if (iommu->iommu_flushinv) {
                 iommu_write(iommu->iommu_flushinv, ~(u64)0);
         } else {
@@ -87,94 +89,6 @@ static inline void iopte_make_dummy(struct iommu *iommu, iopte_t *iopte)
         iopte_val(*iopte) = val;
 }
 
-/* Based almost entirely upon the ppc64 iommu allocator.  If you use the 'handle'
- * facility it must all be done in one pass while under the iommu lock.
- *
- * On sun4u platforms, we only flush the IOMMU once every time we've passed
- * over the entire page table doing allocations.  Therefore we only ever advance
- * the hint and cannot backtrack it.
- */
-unsigned long iommu_range_alloc(struct device *dev,
-                                struct iommu *iommu,
-                                unsigned long npages,
-                                unsigned long *handle)
-{
-        unsigned long n, end, start, limit, boundary_size;
-        struct iommu_arena *arena = &iommu->arena;
-        int pass = 0;
-
-        /* This allocator was derived from x86_64's bit string search */
-
-        /* Sanity check */
-        if (unlikely(npages == 0)) {
-                if (printk_ratelimit())
-                        WARN_ON(1);
-                return DMA_ERROR_CODE;
-        }
-
-        if (handle && *handle)
-                start = *handle;
-        else
-                start = arena->hint;
-
-        limit = arena->limit;
-
-        /* The case below can happen if we have a small segment appended
-         * to a large, or when the previous alloc was at the very end of
-         * the available space. If so, go back to the beginning and flush.
-         */
-        if (start >= limit) {
-                start = 0;
-                if (iommu->flush_all)
-                        iommu->flush_all(iommu);
-        }
-
- again:
-
-        if (dev)
-                boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
-                                      1 << IO_PAGE_SHIFT);
-        else
-                boundary_size = ALIGN(1UL << 32, 1 << IO_PAGE_SHIFT);
-
-        n = iommu_area_alloc(arena->map, limit, start, npages,
-                             iommu->page_table_map_base >> IO_PAGE_SHIFT,
-                             boundary_size >> IO_PAGE_SHIFT, 0);
-        if (n == -1) {
-                if (likely(pass < 1)) {
-                        /* First failure, rescan from the beginning.  */
-                        start = 0;
-                        if (iommu->flush_all)
-                                iommu->flush_all(iommu);
-                        pass++;
-                        goto again;
-                } else {
-                        /* Second failure, give up */
-                        return DMA_ERROR_CODE;
-                }
-        }
-
-        end = n + npages;
-
-        arena->hint = end;
-
-        /* Update handle for SG allocations */
-        if (handle)
-                *handle = end;
-
-        return n;
-}
-
-void iommu_range_free(struct iommu *iommu, dma_addr_t dma_addr, unsigned long npages)
-{
-        struct iommu_arena *arena = &iommu->arena;
-        unsigned long entry;
-
-        entry = (dma_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
-
-        bitmap_clear(arena->map, entry, npages);
-}
-
 int iommu_table_init(struct iommu *iommu, int tsbsize,
                      u32 dma_offset, u32 dma_addr_mask,
                      int numa_node)
@@ -187,22 +101,20 @@ int iommu_table_init(struct iommu *iommu, int tsbsize,
         /* Setup initial software IOMMU state. */
         spin_lock_init(&iommu->lock);
         iommu->ctx_lowest_free = 1;
-        iommu->page_table_map_base = dma_offset;
+        iommu->tbl.table_map_base = dma_offset;
         iommu->dma_addr_mask = dma_addr_mask;
 
         /* Allocate and initialize the free area map.  */
         sz = num_tsb_entries / 8;
         sz = (sz + 7UL) & ~7UL;
-        iommu->arena.map = kmalloc_node(sz, GFP_KERNEL, numa_node);
-        if (!iommu->arena.map) {
-                printk(KERN_ERR "IOMMU: Error, kmalloc(arena.map) failed.\n");
+        iommu->tbl.map = kmalloc_node(sz, GFP_KERNEL, numa_node);
+        if (!iommu->tbl.map)
                 return -ENOMEM;
-        }
-        memset(iommu->arena.map, 0, sz);
-        iommu->arena.limit = num_tsb_entries;
+        memset(iommu->tbl.map, 0, sz);
 
-        if (tlb_type != hypervisor)
-                iommu->flush_all = iommu_flushall;
+        iommu_tbl_pool_init(&iommu->tbl, num_tsb_entries, IO_PAGE_SHIFT,
+                            (tlb_type != hypervisor ? iommu_flushall : NULL),
+                            false, 1, false);
 
         /* Allocate and initialize the dummy page which we
          * set inactive IO PTEs to point to.
@@ -235,18 +147,20 @@ out_free_dummy_page:
         iommu->dummy_page = 0UL;
 
 out_free_map:
-        kfree(iommu->arena.map);
-        iommu->arena.map = NULL;
+        kfree(iommu->tbl.map);
+        iommu->tbl.map = NULL;
 
         return -ENOMEM;
 }
 
-static inline iopte_t *alloc_npages(struct device *dev, struct iommu *iommu,
+static inline iopte_t *alloc_npages(struct device *dev,
+                                    struct iommu *iommu,
                                     unsigned long npages)
 {
         unsigned long entry;
 
-        entry = iommu_range_alloc(dev, iommu, npages, NULL);
+        entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL,
+                                      (unsigned long)(-1), 0);
         if (unlikely(entry == DMA_ERROR_CODE))
                 return NULL;
 
@@ -284,7 +198,7 @@ static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
                                    dma_addr_t *dma_addrp, gfp_t gfp,
                                    struct dma_attrs *attrs)
 {
-        unsigned long flags, order, first_page;
+        unsigned long order, first_page;
         struct iommu *iommu;
         struct page *page;
         int npages, nid;
@@ -306,16 +220,14 @@ static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
 
         iommu = dev->archdata.iommu;
 
-        spin_lock_irqsave(&iommu->lock, flags);
         iopte = alloc_npages(dev, iommu, size >> IO_PAGE_SHIFT);
-        spin_unlock_irqrestore(&iommu->lock, flags);
 
         if (unlikely(iopte == NULL)) {
                 free_pages(first_page, order);
                 return NULL;
         }
 
-        *dma_addrp = (iommu->page_table_map_base +
+        *dma_addrp = (iommu->tbl.table_map_base +
                       ((iopte - iommu->page_table) << IO_PAGE_SHIFT));
         ret = (void *) first_page;
         npages = size >> IO_PAGE_SHIFT;
@@ -336,16 +248,12 @@ static void dma_4u_free_coherent(struct device *dev, size_t size,
                                  struct dma_attrs *attrs)
 {
         struct iommu *iommu;
-        unsigned long flags, order, npages;
+        unsigned long order, npages;
 
         npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
         iommu = dev->archdata.iommu;
 
-        spin_lock_irqsave(&iommu->lock, flags);
-
-        iommu_range_free(iommu, dvma, npages);
-
-        spin_unlock_irqrestore(&iommu->lock, flags);
+        iommu_tbl_range_free(&iommu->tbl, dvma, npages, DMA_ERROR_CODE);
 
         order = get_order(size);
         if (order < 10)
@@ -375,8 +283,8 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
         npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
         npages >>= IO_PAGE_SHIFT;
 
-        spin_lock_irqsave(&iommu->lock, flags);
         base = alloc_npages(dev, iommu, npages);
+        spin_lock_irqsave(&iommu->lock, flags);
         ctx = 0;
         if (iommu->iommu_ctxflush)
                 ctx = iommu_alloc_ctx(iommu);
@@ -385,7 +293,7 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
         if (unlikely(!base))
                 goto bad;
 
-        bus_addr = (iommu->page_table_map_base +
+        bus_addr = (iommu->tbl.table_map_base +
                     ((base - iommu->page_table) << IO_PAGE_SHIFT));
         ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
         base_paddr = __pa(oaddr & IO_PAGE_MASK);
@@ -496,7 +404,7 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
         npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
         npages >>= IO_PAGE_SHIFT;
         base = iommu->page_table +
-                ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+                ((bus_addr - iommu->tbl.table_map_base) >> IO_PAGE_SHIFT);
         bus_addr &= IO_PAGE_MASK;
 
         spin_lock_irqsave(&iommu->lock, flags);
@@ -515,11 +423,10 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
         for (i = 0; i < npages; i++)
                 iopte_make_dummy(iommu, base + i);
 
-        iommu_range_free(iommu, bus_addr, npages);
-
         iommu_free_ctx(iommu, ctx);
-
         spin_unlock_irqrestore(&iommu->lock, flags);
+
+        iommu_tbl_range_free(&iommu->tbl, bus_addr, npages, DMA_ERROR_CODE);
 }
 
 static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -567,7 +474,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
         max_seg_size = dma_get_max_seg_size(dev);
         seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
                                   IO_PAGE_SIZE) >> IO_PAGE_SHIFT;
-        base_shift = iommu->page_table_map_base >> IO_PAGE_SHIFT;
+        base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
         for_each_sg(sglist, s, nelems, i) {
                 unsigned long paddr, npages, entry, out_entry = 0, slen;
                 iopte_t *base;
@@ -581,7 +488,8 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
                 /* Allocate iommu entries for that segment */
                 paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
                 npages = iommu_num_pages(paddr, slen, IO_PAGE_SIZE);
-                entry = iommu_range_alloc(dev, iommu, npages, &handle);
+                entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages,
+                                              &handle, (unsigned long)(-1), 0);
 
                 /* Handle failure */
                 if (unlikely(entry == DMA_ERROR_CODE)) {
@@ -594,7 +502,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
                 base = iommu->page_table + entry;
 
                 /* Convert entry to a dma_addr_t */
-                dma_addr = iommu->page_table_map_base +
+                dma_addr = iommu->tbl.table_map_base +
                         (entry << IO_PAGE_SHIFT);
                 dma_addr |= (s->offset & ~IO_PAGE_MASK);
 
@@ -654,15 +562,17 @@ iommu_map_failed:
                         vaddr = s->dma_address & IO_PAGE_MASK;
                         npages = iommu_num_pages(s->dma_address, s->dma_length,
                                                  IO_PAGE_SIZE);
-                        iommu_range_free(iommu, vaddr, npages);
 
-                        entry = (vaddr - iommu->page_table_map_base)
+                        entry = (vaddr - iommu->tbl.table_map_base)
                                 >> IO_PAGE_SHIFT;
                         base = iommu->page_table + entry;
 
                         for (j = 0; j < npages; j++)
                                 iopte_make_dummy(iommu, base + j);
 
+                        iommu_tbl_range_free(&iommu->tbl, vaddr, npages,
+                                             DMA_ERROR_CODE);
+
                         s->dma_address = DMA_ERROR_CODE;
                         s->dma_length = 0;
                 }
@@ -684,10 +594,11 @@ static unsigned long fetch_sg_ctx(struct iommu *iommu, struct scatterlist *sg)
         if (iommu->iommu_ctxflush) {
                 iopte_t *base;
                 u32 bus_addr;
+                struct iommu_map_table *tbl = &iommu->tbl;
 
                 bus_addr = sg->dma_address & IO_PAGE_MASK;
                 base = iommu->page_table +
-                        ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+                        ((bus_addr - tbl->table_map_base) >> IO_PAGE_SHIFT);
 
                 ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
         }
@@ -723,9 +634,8 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
                 if (!len)
                         break;
                 npages = iommu_num_pages(dma_handle, len, IO_PAGE_SIZE);
-                iommu_range_free(iommu, dma_handle, npages);
 
-                entry = ((dma_handle - iommu->page_table_map_base)
+                entry = ((dma_handle - iommu->tbl.table_map_base)
                          >> IO_PAGE_SHIFT);
                 base = iommu->page_table + entry;
 
@@ -737,6 +647,8 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
                 for (i = 0; i < npages; i++)
                         iopte_make_dummy(iommu, base + i);
 
+                iommu_tbl_range_free(&iommu->tbl, dma_handle, npages,
+                                     DMA_ERROR_CODE);
                 sg = sg_next(sg);
         }
 
@@ -770,9 +682,10 @@ static void dma_4u_sync_single_for_cpu(struct device *dev,
         if (iommu->iommu_ctxflush &&
             strbuf->strbuf_ctxflush) {
                 iopte_t *iopte;
+                struct iommu_map_table *tbl = &iommu->tbl;
 
                 iopte = iommu->page_table +
-                        ((bus_addr - iommu->page_table_map_base)>>IO_PAGE_SHIFT);
+                        ((bus_addr - tbl->table_map_base)>>IO_PAGE_SHIFT);
                 ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
         }
 
@@ -805,9 +718,10 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
         if (iommu->iommu_ctxflush &&
             strbuf->strbuf_ctxflush) {
                 iopte_t *iopte;
+                struct iommu_map_table *tbl = &iommu->tbl;
 
-                iopte = iommu->page_table +
-                        ((sglist[0].dma_address - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+                iopte = iommu->page_table + ((sglist[0].dma_address -
+                        tbl->table_map_base) >> IO_PAGE_SHIFT);
                 ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
         }