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[RFC PATCH v3 1/6] swiotlb: Add io_tlb_mem struct



Added a new struct, io_tlb_mem, as the IO TLB memory pool descriptor and
moved relevant global variables into that struct.
This will be useful later to allow for restricted DMA pool.

Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
---
 arch/powerpc/platforms/pseries/svm.c |   4 +-
 drivers/xen/swiotlb-xen.c            |   4 +-
 include/linux/swiotlb.h              |  39 +++-
 kernel/dma/swiotlb.c                 | 292 +++++++++++++--------------
 4 files changed, 178 insertions(+), 161 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/svm.c 
b/arch/powerpc/platforms/pseries/svm.c
index 7b739cc7a8a9..2b767f1ca5fd 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c
@@ -55,8 +55,8 @@ void __init svm_swiotlb_init(void)
        if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, false))
                return;
 
-       if (io_tlb_start)
-               memblock_free_early(io_tlb_start,
+       if (io_tlb_default_mem.start)
+               memblock_free_early(io_tlb_default_mem.start,
                                    PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
        panic("SVM: Cannot allocate SWIOTLB buffer");
 }
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 2b385c1b4a99..4d17dff7ffd2 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -192,8 +192,8 @@ int __ref xen_swiotlb_init(int verbose, bool early)
        /*
         * IO TLB memory already allocated. Just use it.
         */
-       if (io_tlb_start != 0) {
-               xen_io_tlb_start = phys_to_virt(io_tlb_start);
+       if (io_tlb_default_mem.start != 0) {
+               xen_io_tlb_start = phys_to_virt(io_tlb_default_mem.start);
                goto end;
        }
 
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index d9c9fc9ca5d2..dd8eb57cbb8f 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -70,11 +70,46 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
 
 #ifdef CONFIG_SWIOTLB
 extern enum swiotlb_force swiotlb_force;
-extern phys_addr_t io_tlb_start, io_tlb_end;
+
+/**
+ * struct io_tlb_mem - IO TLB Memory Pool Descriptor
+ *
+ * @start:     The start address of the swiotlb memory pool. Used to do a quick
+ *             range check to see if the memory was in fact allocated by this
+ *             API.
+ * @end:       The end address of the swiotlb memory pool. Used to do a quick
+ *             range check to see if the memory was in fact allocated by this
+ *             API.
+ * @nslabs:    The number of IO TLB blocks (in groups of 64) between @start and
+ *             @end. This is command line adjustable via setup_io_tlb_npages.
+ * @used:      The number of used IO TLB block.
+ * @list:      The free list describing the number of free entries available
+ *             from each index.
+ * @index:     The index to start searching in the next round.
+ * @orig_addr: The original address corresponding to a mapped entry for the
+ *             sync operations.
+ * @lock:      The lock to protect the above data structures in the map and
+ *             unmap calls.
+ * @debugfs:   The dentry to debugfs.
+ */
+struct io_tlb_mem {
+       phys_addr_t start;
+       phys_addr_t end;
+       unsigned long nslabs;
+       unsigned long used;
+       unsigned int *list;
+       unsigned int index;
+       phys_addr_t *orig_addr;
+       spinlock_t lock;
+       struct dentry *debugfs;
+};
+extern struct io_tlb_mem io_tlb_default_mem;
 
 static inline bool is_swiotlb_buffer(phys_addr_t paddr)
 {
-       return paddr >= io_tlb_start && paddr < io_tlb_end;
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+
+       return paddr >= mem->start && paddr < mem->end;
 }
 
 void __init swiotlb_exit(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 7c42df6e6100..e4368159f88a 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -61,33 +61,11 @@
  * allocate a contiguous 1MB, we're probably in trouble anyway.
  */
 #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
+#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
 
 enum swiotlb_force swiotlb_force;
 
-/*
- * Used to do a quick range check in swiotlb_tbl_unmap_single and
- * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by 
this
- * API.
- */
-phys_addr_t io_tlb_start, io_tlb_end;
-
-/*
- * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
- * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
- */
-static unsigned long io_tlb_nslabs;
-
-/*
- * The number of used IO TLB block
- */
-static unsigned long io_tlb_used;
-
-/*
- * This is a free list describing the number of free entries available from
- * each index
- */
-static unsigned int *io_tlb_list;
-static unsigned int io_tlb_index;
+struct io_tlb_mem io_tlb_default_mem;
 
 /*
  * Max segment that we can provide which (if pages are contingous) will
@@ -95,27 +73,17 @@ static unsigned int io_tlb_index;
  */
 static unsigned int max_segment;
 
-/*
- * We need to save away the original address corresponding to a mapped entry
- * for the sync operations.
- */
-#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
-static phys_addr_t *io_tlb_orig_addr;
-
-/*
- * Protect the above data structures in the map and unmap calls
- */
-static DEFINE_SPINLOCK(io_tlb_lock);
-
 static int late_alloc;
 
 static int __init
 setup_io_tlb_npages(char *str)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+
        if (isdigit(*str)) {
-               io_tlb_nslabs = simple_strtoul(str, &str, 0);
+               mem->nslabs = simple_strtoul(str, &str, 0);
                /* avoid tail segment of size < IO_TLB_SEGSIZE */
-               io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+               mem->nslabs = ALIGN(mem->nslabs, IO_TLB_SEGSIZE);
        }
        if (*str == ',')
                ++str;
@@ -123,7 +91,7 @@ setup_io_tlb_npages(char *str)
                swiotlb_force = SWIOTLB_FORCE;
        } else if (!strcmp(str, "noforce")) {
                swiotlb_force = SWIOTLB_NO_FORCE;
-               io_tlb_nslabs = 1;
+               mem->nslabs = 1;
        }
 
        return 0;
@@ -134,7 +102,7 @@ static bool no_iotlb_memory;
 
 unsigned long swiotlb_nr_tbl(void)
 {
-       return unlikely(no_iotlb_memory) ? 0 : io_tlb_nslabs;
+       return unlikely(no_iotlb_memory) ? 0 : io_tlb_default_mem.nslabs;
 }
 EXPORT_SYMBOL_GPL(swiotlb_nr_tbl);
 
@@ -156,13 +124,14 @@ unsigned long swiotlb_size_or_default(void)
 {
        unsigned long size;
 
-       size = io_tlb_nslabs << IO_TLB_SHIFT;
+       size = io_tlb_default_mem.nslabs << IO_TLB_SHIFT;
 
        return size ? size : (IO_TLB_DEFAULT_SIZE);
 }
 
 void __init swiotlb_adjust_size(unsigned long new_size)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        unsigned long size;
 
        /*
@@ -170,10 +139,10 @@ void __init swiotlb_adjust_size(unsigned long new_size)
         * architectures such as those supporting memory encryption to
         * adjust/expand SWIOTLB size for their use.
         */
-       if (!io_tlb_nslabs) {
+       if (!mem->nslabs) {
                size = ALIGN(new_size, 1 << IO_TLB_SHIFT);
-               io_tlb_nslabs = size >> IO_TLB_SHIFT;
-               io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+               mem->nslabs = size >> IO_TLB_SHIFT;
+               mem->nslabs = ALIGN(mem->nslabs, IO_TLB_SEGSIZE);
 
                pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 
20);
        }
@@ -181,14 +150,15 @@ void __init swiotlb_adjust_size(unsigned long new_size)
 
 void swiotlb_print_info(void)
 {
-       unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+       unsigned long bytes = mem->nslabs << IO_TLB_SHIFT;
 
        if (no_iotlb_memory) {
                pr_warn("No low mem\n");
                return;
        }
 
-       pr_info("mapped [mem %pa-%pa] (%luMB)\n", &io_tlb_start, &io_tlb_end,
+       pr_info("mapped [mem %pa-%pa] (%luMB)\n", &mem->start, &mem->end,
               bytes >> 20);
 }
 
@@ -200,57 +170,59 @@ void swiotlb_print_info(void)
  */
 void __init swiotlb_update_mem_attributes(void)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        void *vaddr;
        unsigned long bytes;
 
        if (no_iotlb_memory || late_alloc)
                return;
 
-       vaddr = phys_to_virt(io_tlb_start);
-       bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
+       vaddr = phys_to_virt(mem->start);
+       bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
        set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
        memset(vaddr, 0, bytes);
 }
 
 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        unsigned long i, bytes;
        size_t alloc_size;
 
        bytes = nslabs << IO_TLB_SHIFT;
 
-       io_tlb_nslabs = nslabs;
-       io_tlb_start = __pa(tlb);
-       io_tlb_end = io_tlb_start + bytes;
+       mem->nslabs = nslabs;
+       mem->start = __pa(tlb);
+       mem->end = mem->start + bytes;
 
        /*
         * Allocate and initialize the free list array.  This array is used
         * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
-        * between io_tlb_start and io_tlb_end.
+        * between mem->start and mem->end.
         */
-       alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(int));
-       io_tlb_list = memblock_alloc(alloc_size, PAGE_SIZE);
-       if (!io_tlb_list)
+       alloc_size = PAGE_ALIGN(mem->nslabs * sizeof(int));
+       mem->list = memblock_alloc(alloc_size, PAGE_SIZE);
+       if (!mem->list)
                panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
                      __func__, alloc_size, PAGE_SIZE);
 
-       alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t));
-       io_tlb_orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
-       if (!io_tlb_orig_addr)
+       alloc_size = PAGE_ALIGN(mem->nslabs * sizeof(phys_addr_t));
+       mem->orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
+       if (!mem->orig_addr)
                panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
                      __func__, alloc_size, PAGE_SIZE);
 
-       for (i = 0; i < io_tlb_nslabs; i++) {
-               io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-               io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+       for (i = 0; i < mem->nslabs; i++) {
+               mem->list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+               mem->orig_addr[i] = INVALID_PHYS_ADDR;
        }
-       io_tlb_index = 0;
+       mem->index = 0;
        no_iotlb_memory = false;
 
        if (verbose)
                swiotlb_print_info();
 
-       swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+       swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
        return 0;
 }
 
@@ -261,26 +233,27 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long 
nslabs, int verbose)
 void  __init
 swiotlb_init(int verbose)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        size_t default_size = IO_TLB_DEFAULT_SIZE;
        unsigned char *vstart;
        unsigned long bytes;
 
-       if (!io_tlb_nslabs) {
-               io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-               io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+       if (!mem->nslabs) {
+               mem->nslabs = (default_size >> IO_TLB_SHIFT);
+               mem->nslabs = ALIGN(mem->nslabs, IO_TLB_SEGSIZE);
        }
 
-       bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+       bytes = mem->nslabs << IO_TLB_SHIFT;
 
        /* Get IO TLB memory from the low pages */
        vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);
-       if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
+       if (vstart && !swiotlb_init_with_tbl(vstart, mem->nslabs, verbose))
                return;
 
-       if (io_tlb_start) {
-               memblock_free_early(io_tlb_start,
-                                   PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
-               io_tlb_start = 0;
+       if (mem->start) {
+               memblock_free_early(mem->start,
+                                   PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT));
+               mem->start = 0;
        }
        pr_warn("Cannot allocate buffer");
        no_iotlb_memory = true;
@@ -294,22 +267,23 @@ swiotlb_init(int verbose)
 int
 swiotlb_late_init_with_default_size(size_t default_size)
 {
-       unsigned long bytes, req_nslabs = io_tlb_nslabs;
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+       unsigned long bytes, req_nslabs = mem->nslabs;
        unsigned char *vstart = NULL;
        unsigned int order;
        int rc = 0;
 
-       if (!io_tlb_nslabs) {
-               io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
-               io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+       if (!mem->nslabs) {
+               mem->nslabs = (default_size >> IO_TLB_SHIFT);
+               mem->nslabs = ALIGN(mem->nslabs, IO_TLB_SEGSIZE);
        }
 
        /*
         * Get IO TLB memory from the low pages
         */
-       order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
-       io_tlb_nslabs = SLABS_PER_PAGE << order;
-       bytes = io_tlb_nslabs << IO_TLB_SHIFT;
+       order = get_order(mem->nslabs << IO_TLB_SHIFT);
+       mem->nslabs = SLABS_PER_PAGE << order;
+       bytes = mem->nslabs << IO_TLB_SHIFT;
 
        while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
                vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
@@ -320,15 +294,15 @@ swiotlb_late_init_with_default_size(size_t default_size)
        }
 
        if (!vstart) {
-               io_tlb_nslabs = req_nslabs;
+               mem->nslabs = req_nslabs;
                return -ENOMEM;
        }
        if (order != get_order(bytes)) {
                pr_warn("only able to allocate %ld MB\n",
                        (PAGE_SIZE << order) >> 20);
-               io_tlb_nslabs = SLABS_PER_PAGE << order;
+               mem->nslabs = SLABS_PER_PAGE << order;
        }
-       rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);
+       rc = swiotlb_late_init_with_tbl(vstart, mem->nslabs);
        if (rc)
                free_pages((unsigned long)vstart, order);
 
@@ -337,22 +311,25 @@ swiotlb_late_init_with_default_size(size_t default_size)
 
 static void swiotlb_cleanup(void)
 {
-       io_tlb_end = 0;
-       io_tlb_start = 0;
-       io_tlb_nslabs = 0;
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+
+       mem->end = 0;
+       mem->start = 0;
+       mem->nslabs = 0;
        max_segment = 0;
 }
 
 int
 swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        unsigned long i, bytes;
 
        bytes = nslabs << IO_TLB_SHIFT;
 
-       io_tlb_nslabs = nslabs;
-       io_tlb_start = virt_to_phys(tlb);
-       io_tlb_end = io_tlb_start + bytes;
+       mem->nslabs = nslabs;
+       mem->start = virt_to_phys(tlb);
+       mem->end = mem->start + bytes;
 
        set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
        memset(tlb, 0, bytes);
@@ -360,39 +337,39 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long 
nslabs)
        /*
         * Allocate and initialize the free list array.  This array is used
         * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
-        * between io_tlb_start and io_tlb_end.
+        * between mem->start and mem->end.
         */
-       io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
-                                     get_order(io_tlb_nslabs * sizeof(int)));
-       if (!io_tlb_list)
+       mem->list = (unsigned int *)__get_free_pages(GFP_KERNEL,
+                                     get_order(mem->nslabs * sizeof(int)));
+       if (!mem->list)
                goto cleanup3;
 
-       io_tlb_orig_addr = (phys_addr_t *)
+       mem->orig_addr = (phys_addr_t *)
                __get_free_pages(GFP_KERNEL,
-                                get_order(io_tlb_nslabs *
+                                get_order(mem->nslabs *
                                           sizeof(phys_addr_t)));
-       if (!io_tlb_orig_addr)
+       if (!mem->orig_addr)
                goto cleanup4;
 
-       for (i = 0; i < io_tlb_nslabs; i++) {
-               io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
-               io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+       for (i = 0; i < mem->nslabs; i++) {
+               mem->list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+               mem->orig_addr[i] = INVALID_PHYS_ADDR;
        }
-       io_tlb_index = 0;
+       mem->index = 0;
        no_iotlb_memory = false;
 
        swiotlb_print_info();
 
        late_alloc = 1;
 
-       swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT);
+       swiotlb_set_max_segment(mem->nslabs << IO_TLB_SHIFT);
 
        return 0;
 
 cleanup4:
-       free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-                                                        sizeof(int)));
-       io_tlb_list = NULL;
+       free_pages((unsigned long)mem->list,
+                  get_order(mem->nslabs * sizeof(int)));
+       mem->list = NULL;
 cleanup3:
        swiotlb_cleanup();
        return -ENOMEM;
@@ -400,23 +377,25 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long 
nslabs)
 
 void __init swiotlb_exit(void)
 {
-       if (!io_tlb_orig_addr)
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+
+       if (!mem->orig_addr)
                return;
 
        if (late_alloc) {
-               free_pages((unsigned long)io_tlb_orig_addr,
-                          get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
-               free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
-                                                                sizeof(int)));
-               free_pages((unsigned long)phys_to_virt(io_tlb_start),
-                          get_order(io_tlb_nslabs << IO_TLB_SHIFT));
+               free_pages((unsigned long)mem->orig_addr,
+                          get_order(mem->nslabs * sizeof(phys_addr_t)));
+               free_pages((unsigned long)mem->list,
+                          get_order(mem->nslabs * sizeof(int)));
+               free_pages((unsigned long)phys_to_virt(mem->start),
+                          get_order(mem->nslabs << IO_TLB_SHIFT));
        } else {
-               memblock_free_late(__pa(io_tlb_orig_addr),
-                                  PAGE_ALIGN(io_tlb_nslabs * 
sizeof(phys_addr_t)));
-               memblock_free_late(__pa(io_tlb_list),
-                                  PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
-               memblock_free_late(io_tlb_start,
-                                  PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
+               memblock_free_late(__pa(mem->orig_addr),
+                                  PAGE_ALIGN(mem->nslabs * 
sizeof(phys_addr_t)));
+               memblock_free_late(__pa(mem->list),
+                                  PAGE_ALIGN(mem->nslabs * sizeof(int)));
+               memblock_free_late(mem->start,
+                                  PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT));
        }
        swiotlb_cleanup();
 }
@@ -465,7 +444,8 @@ 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);
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+       dma_addr_t tbl_dma_addr = phys_to_dma_unencrypted(hwdev, mem->start);
        unsigned long flags;
        phys_addr_t tlb_addr;
        unsigned int nslots, stride, index, wrap;
@@ -516,13 +496,13 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 
phys_addr_t orig_addr,
         * 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);
+       spin_lock_irqsave(&mem->lock, flags);
 
-       if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
+       if (unlikely(nslots > mem->nslabs - mem->used))
                goto not_found;
 
-       index = ALIGN(io_tlb_index, stride);
-       if (index >= io_tlb_nslabs)
+       index = ALIGN(mem->index, stride);
+       if (index >= mem->nslabs)
                index = 0;
        wrap = index;
 
@@ -530,7 +510,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 
phys_addr_t orig_addr,
                while (iommu_is_span_boundary(index, nslots, offset_slots,
                                              max_slots)) {
                        index += stride;
-                       if (index >= io_tlb_nslabs)
+                       if (index >= mem->nslabs)
                                index = 0;
                        if (index == wrap)
                                goto not_found;
@@ -541,40 +521,40 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 
phys_addr_t orig_addr,
                 * contiguous buffers, we allocate the buffers from that slot
                 * and mark the entries as '0' indicating unavailable.
                 */
-               if (io_tlb_list[index] >= nslots) {
+               if (mem->list[index] >= nslots) {
                        int count = 0;
 
                        for (i = index; i < (int) (index + nslots); i++)
-                               io_tlb_list[i] = 0;
-                       for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != 
IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
-                               io_tlb_list[i] = ++count;
-                       tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);
+                               mem->list[i] = 0;
+                       for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != 
IO_TLB_SEGSIZE - 1) && mem->list[i]; i--)
+                               mem->list[i] = ++count;
+                       tlb_addr = mem->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);
+                       mem->index = ((index + nslots) < mem->nslabs
+                                     ? (index + nslots) : 0);
 
                        goto found;
                }
                index += stride;
-               if (index >= io_tlb_nslabs)
+               if (index >= mem->nslabs)
                        index = 0;
        } while (index != wrap);
 
 not_found:
-       tmp_io_tlb_used = io_tlb_used;
+       tmp_io_tlb_used = mem->used;
 
-       spin_unlock_irqrestore(&io_tlb_lock, flags);
+       spin_unlock_irqrestore(&mem->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);
+                        alloc_size, mem->nslabs, tmp_io_tlb_used);
        return (phys_addr_t)DMA_MAPPING_ERROR;
 found:
-       io_tlb_used += nslots;
-       spin_unlock_irqrestore(&io_tlb_lock, flags);
+       mem->used += nslots;
+       spin_unlock_irqrestore(&mem->lock, flags);
 
        /*
         * Save away the mapping from the original address to the DMA address.
@@ -582,7 +562,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 
phys_addr_t orig_addr,
         * needed.
         */
        for (i = 0; i < nslots; i++)
-               io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
+               mem->orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
        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);
@@ -597,10 +577,11 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, 
phys_addr_t tlb_addr,
                              size_t mapping_size, size_t alloc_size,
                              enum dma_data_direction dir, unsigned long attrs)
 {
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
        unsigned long flags;
        int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> 
IO_TLB_SHIFT;
-       int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-       phys_addr_t orig_addr = io_tlb_orig_addr[index];
+       int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
+       phys_addr_t orig_addr = mem->orig_addr[index];
 
        /*
         * First, sync the memory before unmapping the entry
@@ -616,36 +597,37 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, 
phys_addr_t tlb_addr,
         * While returning the entries to the free list, we merge the entries
         * with slots below and above the pool being returned.
         */
-       spin_lock_irqsave(&io_tlb_lock, flags);
+       spin_lock_irqsave(&mem->lock, flags);
        {
                count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
-                        io_tlb_list[index + nslots] : 0);
+                        mem->list[index + nslots] : 0);
                /*
                 * Step 1: return the slots to the free list, merging the
                 * slots with superceeding slots
                 */
                for (i = index + nslots - 1; i >= index; i--) {
-                       io_tlb_list[i] = ++count;
-                       io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+                       mem->list[i] = ++count;
+                       mem->orig_addr[i] = INVALID_PHYS_ADDR;
                }
                /*
                 * Step 2: merge the returned slots with the preceding slots,
                 * if available (non zero)
                 */
-               for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != 
IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
-                       io_tlb_list[i] = ++count;
+               for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != 
IO_TLB_SEGSIZE -1) && mem->list[i]; i--)
+                       mem->list[i] = ++count;
 
-               io_tlb_used -= nslots;
+               mem->used -= nslots;
        }
-       spin_unlock_irqrestore(&io_tlb_lock, flags);
+       spin_unlock_irqrestore(&mem->lock, flags);
 }
 
 void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
                             size_t size, enum dma_data_direction dir,
                             enum dma_sync_target target)
 {
-       int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
-       phys_addr_t orig_addr = io_tlb_orig_addr[index];
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
+       int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
+       phys_addr_t orig_addr = mem->orig_addr[index];
 
        if (orig_addr == INVALID_PHYS_ADDR)
                return;
@@ -713,21 +695,21 @@ size_t swiotlb_max_mapping_size(struct device *dev)
 bool is_swiotlb_active(void)
 {
        /*
-        * When SWIOTLB is initialized, even if io_tlb_start points to physical
-        * address zero, io_tlb_end surely doesn't.
+        * When SWIOTLB is initialized, even if mem->start points to physical
+        * address zero, mem->end surely doesn't.
         */
-       return io_tlb_end != 0;
+       return io_tlb_default_mem.end != 0;
 }
 
 #ifdef CONFIG_DEBUG_FS
 
 static int __init swiotlb_create_debugfs(void)
 {
-       struct dentry *root;
+       struct io_tlb_mem *mem = &io_tlb_default_mem;
 
-       root = debugfs_create_dir("swiotlb", NULL);
-       debugfs_create_ulong("io_tlb_nslabs", 0400, root, &io_tlb_nslabs);
-       debugfs_create_ulong("io_tlb_used", 0400, root, &io_tlb_used);
+       mem->debugfs = debugfs_create_dir("swiotlb", NULL);
+       debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs);
+       debugfs_create_ulong("io_tlb_used", 0400, mem->debugfs, &mem->used);
        return 0;
 }
 
-- 
2.29.2.729.g45daf8777d-goog

To make this change as mechanical as possible, I didn't fix any
checkpatch.pl ERROR/WARNING.



 


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