Remove unclear comment about address truncation in busdma. Add (hopefully much clear...

Noted by:	avg

diff --git a/sys/arm/arm/busdma_machdep-v6.c b/sys/arm/arm/busdma_machdep-v6.c
index a945b6371dc8cf441c790614940d5c5ada7f9915..66d461204f1609f2978c6940b806ffd71548811b 100644 (file)
--- a/sys/arm/arm/busdma_machdep-v6.c
+++ b/sys/arm/arm/busdma_machdep-v6.c
@@ -1089,10 +1089,6 @@ _bus_dmamap_load_phys(bus_dma_tag_t dmat,
                                sl++;
                                sl->vaddr = 0;
                                sl->datacount = sgsize;
-                               /*
-                                * PHYS_TO_VM_PAGE() will truncate
-                                * unaligned addresses.
-                                */
                                sl->pages = PHYS_TO_VM_PAGE(curaddr);
                                sl->dataoffs = curaddr & PAGE_MASK;
                        } else
@@ -1214,10 +1210,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
                                sl++;
                                sl->vaddr = kvaddr;
                                sl->datacount = sgsize;
-                               /*
-                                * PHYS_TO_VM_PAGE() will truncate
-                                * unaligned addresses.
-                                */
                                sl->pages = PHYS_TO_VM_PAGE(curaddr);
                                sl->dataoffs = curaddr & PAGE_MASK;
                        } else
@@ -1687,7 +1679,6 @@ add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
                bpage->busaddr |= addr & PAGE_MASK;
        }
        bpage->datavaddr = vaddr;
-       /* PHYS_TO_VM_PAGE() will truncate unaligned addresses. */
        bpage->datapage = PHYS_TO_VM_PAGE(addr);
        bpage->dataoffs = addr & PAGE_MASK;
        bpage->datacount = size;

diff --git a/sys/arm/arm/busdma_machdep.c b/sys/arm/arm/busdma_machdep.c
index e7ec8b1403d77c3eecf4ad82d21f78d27c55d6e2..00c7f2314f98e2adde5ebe6ba1d26056d6526c30 100644 (file)
--- a/sys/arm/arm/busdma_machdep.c
+++ b/sys/arm/arm/busdma_machdep.c
@@ -993,10 +993,6 @@ _bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
                                sl++;
                                sl->vaddr = 0;
                                sl->datacount = sgsize;
-                               /*
-                                * PHYS_TO_VM_PAGE() will truncate
-                                * unaligned addresses.
-                                */
                                sl->pages = PHYS_TO_VM_PAGE(curaddr);
                                sl->dataoffs = curaddr & PAGE_MASK;
                        } else
@@ -1108,10 +1104,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
                                sl++;
                                sl->vaddr = kvaddr;
                                sl->datacount = sgsize;
-                               /*
-                                * PHYS_TO_VM_PAGE() will truncate
-                                * unaligned addresses.
-                                */
                                sl->pages = PHYS_TO_VM_PAGE(curaddr);
                                sl->dataoffs = curaddr & PAGE_MASK;
                        } else
@@ -1541,7 +1533,6 @@ add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
                bpage->busaddr |= addr & PAGE_MASK;
        }
        bpage->datavaddr = vaddr;
-       /* PHYS_TO_VM_PAGE() will truncate unaligned addresses. */
        bpage->datapage = PHYS_TO_VM_PAGE(addr);
        bpage->dataoffs = addr & PAGE_MASK;
        bpage->datacount = size;

diff --git a/sys/arm64/arm64/busdma_bounce.c b/sys/arm64/arm64/busdma_bounce.c
index 1dc071db62be86628b5d459668d8324e0db0ad8d..cd0c087a0077ea5b6ded907b01b48590d1b83cc7 100644 (file)
--- a/sys/arm64/arm64/busdma_bounce.c
+++ b/sys/arm64/arm64/busdma_bounce.c
@@ -1009,7 +1009,6 @@ add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
                bpage->busaddr |= addr & PAGE_MASK;
        }
        bpage->datavaddr = vaddr;
-       /* PHYS_TO_VM_PAGE() will truncate unaligned addresses. */
        bpage->datapage = PHYS_TO_VM_PAGE(addr);
        bpage->dataoffs = addr & PAGE_MASK;
        bpage->datacount = size;

diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index dedd6ac9eb0c2d54bc1a4a3ad390651d5ea39e0d..3dbd7f7015ac452178c83f65c3dc73257897ef3b 100644 (file)
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -375,6 +375,11 @@ extern long first_page;                    /* first physical page number */
 
 #define VM_PAGE_TO_PHYS(entry) ((entry)->phys_addr)
 
+/*
+ * PHYS_TO_VM_PAGE() Returns the vm_page_t object that represents a memory
+ * page to which the given physical address belongs. The correct vm_page_t
+ * object is returned for addresses that are not page-aligned.
+ */
 vm_page_t PHYS_TO_VM_PAGE(vm_paddr_t pa);
 
 /*

diff --git a/sys/x86/x86/busdma_bounce.c b/sys/x86/x86/busdma_bounce.c
index cac6c7158caa89fd969dce7dfedadd9f730de3ed..ebd6238ef820a9f1ffcc3531c41f5e5290876c42 100644 (file)
--- a/sys/x86/x86/busdma_bounce.c
+++ b/sys/x86/x86/busdma_bounce.c
@@ -1006,7 +1006,6 @@ add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
                bpage->busaddr |= addr & PAGE_MASK;
        }
        bpage->datavaddr = vaddr;
-       /* PHYS_TO_VM_PAGE() will truncate unaligned addresses. */
        bpage->datapage = PHYS_TO_VM_PAGE(addr);
        bpage->dataoffs = addr & PAGE_MASK;
        bpage->datacount = size;