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[PATCH 09/15] swiotlb: make the swiotlb_init interface more useful



Pass a bool to pass if swiotlb needs to be enabled based on the
addressing needs and replace the verbose argument with a set of
flags, including one to force enable bounce buffering.

Note that this patch removes the possibility to force xen-swiotlb
use using swiotlb=force on the command line on x86 (arm and arm64
never supported that), but this interface will be restored shortly.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 arch/arm/mm/init.c                     |  6 +----
 arch/arm64/mm/init.c                   |  6 +----
 arch/ia64/mm/init.c                    |  4 +--
 arch/mips/cavium-octeon/dma-octeon.c   |  2 +-
 arch/mips/loongson64/dma.c             |  2 +-
 arch/mips/sibyte/common/dma.c          |  2 +-
 arch/powerpc/mm/mem.c                  |  3 ++-
 arch/powerpc/platforms/pseries/setup.c |  3 ---
 arch/riscv/mm/init.c                   |  8 +-----
 arch/s390/mm/init.c                    |  3 +--
 arch/x86/kernel/pci-dma.c              | 15 ++++++-----
 drivers/xen/swiotlb-xen.c              |  4 +--
 include/linux/swiotlb.h                | 15 ++++++-----
 include/trace/events/swiotlb.h         | 29 ++++++++-------------
 kernel/dma/swiotlb.c                   | 35 ++++++++++++++------------
 15 files changed, 55 insertions(+), 82 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index fe249ea919083..ce64bdb55a16b 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -271,11 +271,7 @@ static void __init free_highpages(void)
 void __init mem_init(void)
 {
 #ifdef CONFIG_ARM_LPAE
-       if (swiotlb_force == SWIOTLB_FORCE ||
-           max_pfn > arm_dma_pfn_limit)
-               swiotlb_init(1);
-       else
-               swiotlb_force = SWIOTLB_NO_FORCE;
+       swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
 #endif
 
        set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 8ac25f19084e8..7b6ea4d6733d6 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -398,11 +398,7 @@ void __init bootmem_init(void)
  */
 void __init mem_init(void)
 {
-       if (swiotlb_force == SWIOTLB_FORCE ||
-           max_pfn > PFN_DOWN(arm64_dma_phys_limit))
-               swiotlb_init(1);
-       else if (!xen_swiotlb_detect())
-               swiotlb_force = SWIOTLB_NO_FORCE;
+       swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE);
 
        /* this will put all unused low memory onto the freelists */
        memblock_free_all();
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 5d165607bf354..3c3e15b22608f 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -437,9 +437,7 @@ mem_init (void)
                if (iommu_detected)
                        break;
 #endif
-#ifdef CONFIG_SWIOTLB
-               swiotlb_init(1);
-#endif
+               swiotlb_init(true, SWIOTLB_VERBOSE);
        } while (0);
 
 #ifdef CONFIG_FLATMEM
diff --git a/arch/mips/cavium-octeon/dma-octeon.c 
b/arch/mips/cavium-octeon/dma-octeon.c
index fb7547e217263..9fbba6a8fa4c5 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -235,5 +235,5 @@ void __init plat_swiotlb_setup(void)
 #endif
 
        swiotlb_adjust_size(swiotlbsize);
-       swiotlb_init(1);
+       swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/mips/loongson64/dma.c b/arch/mips/loongson64/dma.c
index 364f2f27c8723..8220a1bc0db64 100644
--- a/arch/mips/loongson64/dma.c
+++ b/arch/mips/loongson64/dma.c
@@ -24,5 +24,5 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 
 void __init plat_swiotlb_setup(void)
 {
-       swiotlb_init(1);
+       swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/mips/sibyte/common/dma.c b/arch/mips/sibyte/common/dma.c
index eb47a94f3583e..c5c2c782aff68 100644
--- a/arch/mips/sibyte/common/dma.c
+++ b/arch/mips/sibyte/common/dma.c
@@ -10,5 +10,5 @@
 
 void __init plat_swiotlb_setup(void)
 {
-       swiotlb_init(1);
+       swiotlb_init(true, SWIOTLB_VERBOSE);
 }
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8e301cd8925b2..e1519e2edc656 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -17,6 +17,7 @@
 #include <linux/suspend.h>
 #include <linux/dma-direct.h>
 
+#include <asm/swiotlb.h>
 #include <asm/machdep.h>
 #include <asm/rtas.h>
 #include <asm/kasan.h>
@@ -251,7 +252,7 @@ void __init mem_init(void)
        if (is_secure_guest())
                svm_swiotlb_init();
        else
-               swiotlb_init(0);
+               swiotlb_init(ppc_swiotlb_enable, 0);
 #endif
 
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
diff --git a/arch/powerpc/platforms/pseries/setup.c 
b/arch/powerpc/platforms/pseries/setup.c
index 069d7b3bb142e..c6e06d91b6602 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -838,9 +838,6 @@ static void __init pSeries_setup_arch(void)
        }
 
        ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
-
-       if (swiotlb_force == SWIOTLB_FORCE)
-               ppc_swiotlb_enable = 1;
 }
 
 static void pseries_panic(char *str)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9535bea8688c0..181ffd322eafa 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -120,13 +120,7 @@ void __init mem_init(void)
        BUG_ON(!mem_map);
 #endif /* CONFIG_FLATMEM */
 
-#ifdef CONFIG_SWIOTLB
-       if (swiotlb_force == SWIOTLB_FORCE ||
-           max_pfn > PFN_DOWN(dma32_phys_limit))
-               swiotlb_init(1);
-       else
-               swiotlb_force = SWIOTLB_NO_FORCE;
-#endif
+       swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE);
        memblock_free_all();
 
        print_vm_layout();
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 86ffd0d51fd59..6fb6bf64326f9 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -185,8 +185,7 @@ static void pv_init(void)
                return;
 
        /* make sure bounce buffers are shared */
-       swiotlb_force = SWIOTLB_FORCE;
-       swiotlb_init(1);
+       swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
        swiotlb_update_mem_attributes();
 }
 
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 04140e20ef1a3..a705a199bf8a3 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -39,6 +39,7 @@ int iommu_detected __read_mostly = 0;
 
 #ifdef CONFIG_SWIOTLB
 bool x86_swiotlb_enable;
+static unsigned int x86_swiotlb_flags;
 
 static void __init pci_swiotlb_detect(void)
 {
@@ -58,16 +59,16 @@ static void __init pci_swiotlb_detect(void)
         * bounce buffers as the hypervisor can't access arbitrary VM memory
         * that is not explicitly shared with it.
         */
-       if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
-               swiotlb_force = SWIOTLB_FORCE;
-
-       if (swiotlb_force == SWIOTLB_FORCE)
+       if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
                x86_swiotlb_enable = true;
+               x86_swiotlb_flags |= SWIOTLB_FORCE;
+       }
 }
 #else
 static inline void __init pci_swiotlb_detect(void)
 {
 }
+#define x86_swiotlb_flags 0
 #endif /* CONFIG_SWIOTLB */
 
 #ifdef CONFIG_SWIOTLB_XEN
@@ -75,8 +76,7 @@ static bool xen_swiotlb;
 
 static void __init pci_xen_swiotlb_init(void)
 {
-       if (!xen_initial_domain() && !x86_swiotlb_enable &&
-           swiotlb_force != SWIOTLB_FORCE)
+       if (!xen_initial_domain() && !x86_swiotlb_enable)
                return;
        x86_swiotlb_enable = true;
        xen_swiotlb = true;
@@ -120,8 +120,7 @@ void __init pci_iommu_alloc(void)
        gart_iommu_hole_init();
        amd_iommu_detect();
        detect_intel_iommu();
-       if (x86_swiotlb_enable)
-               swiotlb_init(0);
+       swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
 }
 
 /*
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 485cd06ed39e7..c2da3eb4826e8 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -251,7 +251,7 @@ void __init xen_swiotlb_init_early(void)
                panic("%s (rc:%d)", xen_swiotlb_error(XEN_SWIOTLB_EFIXUP), rc);
        }
 
-       if (swiotlb_init_with_tbl(start, nslabs, true))
+       if (swiotlb_init_with_tbl(start, nslabs, SWIOTLB_VERBOSE))
                panic("Cannot allocate SWIOTLB buffer");
 }
 #endif /* CONFIG_X86 */
@@ -376,7 +376,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, 
struct page *page,
        /*
         * Oh well, have to allocate and map a bounce buffer.
         */
-       trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
+       trace_swiotlb_bounced(dev, dev_addr, size);
 
        map = swiotlb_tbl_map_single(dev, phys, size, size, 0, dir, attrs);
        if (map == (phys_addr_t)DMA_MAPPING_ERROR)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index b48b26bfa0edb..ae0407173e845 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -13,11 +13,8 @@ struct device;
 struct page;
 struct scatterlist;
 
-enum swiotlb_force {
-       SWIOTLB_NORMAL,         /* Default - depending on HW DMA mask etc. */
-       SWIOTLB_FORCE,          /* swiotlb=force */
-       SWIOTLB_NO_FORCE,       /* swiotlb=noforce */
-};
+#define SWIOTLB_VERBOSE        (1 << 0) /* verbose initialization */
+#define SWIOTLB_FORCE  (1 << 1) /* force bounce buffering */
 
 /*
  * Maximum allowable number of contiguous slabs to map,
@@ -36,8 +33,7 @@ enum swiotlb_force {
 /* default to 64MB */
 #define IO_TLB_DEFAULT_SIZE (64UL<<20)
 
-extern void swiotlb_init(int verbose);
-int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
+int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags);
 unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
 int swiotlb_init_late(size_t size);
@@ -126,13 +122,16 @@ static inline bool is_swiotlb_force_bounce(struct device 
*dev)
        return mem && mem->force_bounce;
 }
 
+void swiotlb_init(bool addressing_limited, unsigned int flags);
 void __init swiotlb_exit(void);
 unsigned int swiotlb_max_segment(void);
 size_t swiotlb_max_mapping_size(struct device *dev);
 bool is_swiotlb_active(struct device *dev);
 void __init swiotlb_adjust_size(unsigned long size);
 #else
-#define swiotlb_force SWIOTLB_NO_FORCE
+static inline void swiotlb_init(bool addressing_limited, unsigned int flags)
+{
+}
 static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
 {
        return false;
diff --git a/include/trace/events/swiotlb.h b/include/trace/events/swiotlb.h
index 705be43b71ab0..da05c9ebd224a 100644
--- a/include/trace/events/swiotlb.h
+++ b/include/trace/events/swiotlb.h
@@ -8,20 +8,15 @@
 #include <linux/tracepoint.h>
 
 TRACE_EVENT(swiotlb_bounced,
-
-       TP_PROTO(struct device *dev,
-                dma_addr_t dev_addr,
-                size_t size,
-                enum swiotlb_force swiotlb_force),
-
-       TP_ARGS(dev, dev_addr, size, swiotlb_force),
+       TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
+       TP_ARGS(dev, dev_addr, size),
 
        TP_STRUCT__entry(
-               __string(       dev_name,       dev_name(dev)           )
-               __field(        u64,    dma_mask                        )
-               __field(        dma_addr_t,     dev_addr                )
-               __field(        size_t, size                            )
-               __field(        enum swiotlb_force,     swiotlb_force   )
+               __string(dev_name, dev_name(dev))
+               __field(u64, dma_mask)
+               __field(dma_addr_t, dev_addr)
+               __field(size_t, size)
+               __field(bool, force)
        ),
 
        TP_fast_assign(
@@ -29,19 +24,15 @@ TRACE_EVENT(swiotlb_bounced,
                __entry->dma_mask = (dev->dma_mask ? *dev->dma_mask : 0);
                __entry->dev_addr = dev_addr;
                __entry->size = size;
-               __entry->swiotlb_force = swiotlb_force;
+               __entry->force = is_swiotlb_force_bounce(dev);
        ),
 
-       TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
-               "size=%zu %s",
+       TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx size=%zu %s",
                __get_str(dev_name),
                __entry->dma_mask,
                (unsigned long long)__entry->dev_addr,
                __entry->size,
-               __print_symbolic(__entry->swiotlb_force,
-                       { SWIOTLB_NORMAL,       "NORMAL" },
-                       { SWIOTLB_FORCE,        "FORCE" },
-                       { SWIOTLB_NO_FORCE,     "NO_FORCE" }))
+               __entry->force ? "FORCE" : "NORMAL")
 );
 
 #endif /*  _TRACE_SWIOTLB_H */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 9a4fe6e48a074..86e877a96b828 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -62,7 +62,8 @@
 
 #define INVALID_PHYS_ADDR (~(phys_addr_t)0)
 
-enum swiotlb_force swiotlb_force;
+static bool swiotlb_force_bounce;
+static bool swiotlb_force_disable;
 
 struct io_tlb_mem io_tlb_default_mem;
 
@@ -81,9 +82,9 @@ setup_io_tlb_npages(char *str)
        if (*str == ',')
                ++str;
        if (!strcmp(str, "force"))
-               swiotlb_force = SWIOTLB_FORCE;
+               swiotlb_force_bounce = true;
        else if (!strcmp(str, "noforce"))
-               swiotlb_force = SWIOTLB_NO_FORCE;
+               swiotlb_force_disable = true;
 
        return 0;
 }
@@ -202,7 +203,7 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, 
phys_addr_t start,
        mem->index = 0;
        mem->late_alloc = late_alloc;
 
-       if (swiotlb_force == SWIOTLB_FORCE)
+       if (swiotlb_force_bounce)
                mem->force_bounce = true;
 
        spin_lock_init(&mem->lock);
@@ -224,12 +225,13 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem 
*mem, phys_addr_t start,
        return;
 }
 
-int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
+int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs,
+               unsigned int flags)
 {
        struct io_tlb_mem *mem = &io_tlb_default_mem;
        size_t alloc_size;
 
-       if (swiotlb_force == SWIOTLB_NO_FORCE)
+       if (swiotlb_force_disable)
                return 0;
 
        /* protect against double initialization */
@@ -243,8 +245,9 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long 
nslabs, int verbose)
                      __func__, alloc_size, PAGE_SIZE);
 
        swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, false);
+       mem->force_bounce = flags & SWIOTLB_FORCE;
 
-       if (verbose)
+       if (flags & SWIOTLB_VERBOSE)
                swiotlb_print_info();
        return 0;
 }
@@ -253,20 +256,21 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long 
nslabs, int verbose)
  * Statically reserve bounce buffer space and initialize bounce buffer data
  * structures for the software IO TLB used to implement the DMA API.
  */
-void  __init
-swiotlb_init(int verbose)
+void __init swiotlb_init(bool addressing_limit, unsigned int flags)
 {
        size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT);
        void *tlb;
 
-       if (swiotlb_force == SWIOTLB_NO_FORCE)
+       if (!addressing_limit && !swiotlb_force_bounce)
+               return;
+       if (swiotlb_force_disable)
                return;
 
        /* Get IO TLB memory from the low pages */
        tlb = memblock_alloc_low(bytes, PAGE_SIZE);
        if (!tlb)
                goto fail;
-       if (swiotlb_init_with_tbl(tlb, default_nslabs, verbose))
+       if (swiotlb_init_with_tbl(tlb, default_nslabs, flags))
                goto fail_free_mem;
        return;
 
@@ -289,7 +293,7 @@ int swiotlb_init_late(size_t size)
        unsigned int order;
        int rc = 0;
 
-       if (swiotlb_force == SWIOTLB_NO_FORCE)
+       if (swiotlb_force_disable)
                return 0;
 
        /*
@@ -328,7 +332,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
        struct io_tlb_mem *mem = &io_tlb_default_mem;
        unsigned long bytes = nslabs << IO_TLB_SHIFT;
 
-       if (swiotlb_force == SWIOTLB_NO_FORCE)
+       if (swiotlb_force_disable)
                return 0;
 
        /* protect against double initialization */
@@ -353,7 +357,7 @@ void __init swiotlb_exit(void)
        unsigned long tbl_vaddr;
        size_t tbl_size, slots_size;
 
-       if (swiotlb_force == SWIOTLB_FORCE)
+       if (swiotlb_force_bounce)
                return;
 
        if (!mem->nslabs)
@@ -704,8 +708,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t 
paddr, size_t size,
        phys_addr_t swiotlb_addr;
        dma_addr_t dma_addr;
 
-       trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size,
-                             swiotlb_force);
+       trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
 
        swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir,
                        attrs);
-- 
2.30.2




 


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