[src/riastradh-drm2]: src/sys/external/bsd/drm2 Fix kunmap: unlike kunmap_ato...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/04af50f5c8cc
branches:  riastradh-drm2
changeset: 788556:04af50f5c8cc
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Sep 08 16:16:37 2013 +0000

description:
Fix kunmap: unlike kunmap_atomic, it takes a page, not a vaddr.

Unmapping the vaddr where the struct vm_page is stored makes for a
rather confusing state of affairs!

diffstat:

 sys/external/bsd/drm2/include/linux/highmem.h |   4 +-
 sys/external/bsd/drm2/linux/linux_kmap.c      |  95 ++++++++++++++++++++++++--
 2 files changed, 87 insertions(+), 12 deletions(-)

diffs (172 lines):

diff -r 9abab72e2664 -r 04af50f5c8cc sys/external/bsd/drm2/include/linux/highmem.h
--- a/sys/external/bsd/drm2/include/linux/highmem.h     Sun Sep 08 16:15:17 2013 +0000
+++ b/sys/external/bsd/drm2/include/linux/highmem.h     Sun Sep 08 16:16:37 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: highmem.h,v 1.1.2.3 2013/07/24 03:46:22 riastradh Exp $        */
+/*     $NetBSD: highmem.h,v 1.1.2.4 2013/09/08 16:16:37 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -51,6 +51,6 @@
 void   kunmap_atomic(void *);
 
 void * kmap(struct page *);
-void   kunmap(void *);
+void   kunmap(struct page *);
 
 #endif  /* _LINUX_HIGHMEM_H_ */
diff -r 9abab72e2664 -r 04af50f5c8cc sys/external/bsd/drm2/linux/linux_kmap.c
--- a/sys/external/bsd/drm2/linux/linux_kmap.c  Sun Sep 08 16:15:17 2013 +0000
+++ b/sys/external/bsd/drm2/linux/linux_kmap.c  Sun Sep 08 16:16:37 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_kmap.c,v 1.1.2.2 2013/07/24 03:46:22 riastradh Exp $     */
+/*     $NetBSD: linux_kmap.c,v 1.1.2.3 2013/09/08 16:16:37 riastradh Exp $     */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,10 +30,12 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_kmap.c,v 1.1.2.2 2013/07/24 03:46:22 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_kmap.c,v 1.1.2.3 2013/09/08 16:16:37 riastradh Exp $");
 
 #include <sys/types.h>
+#include <sys/kmem.h>
 #include <sys/mutex.h>
+#include <sys/rbtree.h>
 
 #include <uvm/uvm_extern.h>
 
@@ -55,6 +57,51 @@
 static kmutex_t linux_kmap_atomic_lock;
 static vaddr_t linux_kmap_atomic_vaddr;
 
+static kmutex_t linux_kmap_lock;
+static rb_tree_t linux_kmap_entries;
+
+struct linux_kmap_entry {
+       paddr_t         lke_paddr;
+       vaddr_t         lke_vaddr;
+       unsigned int    lke_refcnt;
+       rb_node_t       lke_node;
+};
+
+static int
+lke_compare_nodes(void *ctx __unused, const void *an, const void *bn)
+{
+       const struct linux_kmap_entry *const a = an;
+       const struct linux_kmap_entry *const b = bn;
+
+       if (a->lke_paddr < b->lke_paddr)
+               return -1;
+       else if (a->lke_paddr > b->lke_paddr)
+               return +1;
+       else
+               return 0;
+}
+
+static int
+lke_compare_key(void *ctx __unused, const void *node, const void *key)
+{
+       const struct linux_kmap_entry *const lke = node;
+       const paddr_t *const paddrp = key;
+
+       if (lke->lke_paddr < *paddrp)
+               return -1;
+       else if (lke->lke_paddr > *paddrp)
+               return +1;
+       else
+               return 0;
+}
+
+static const rb_tree_ops_t linux_kmap_entry_ops = {
+       .rbto_compare_nodes = &lke_compare_nodes,
+       .rbto_compare_key = &lke_compare_key,
+       .rbto_node_offset = offsetof(struct linux_kmap_entry, lke_node),
+       .rbto_context = NULL,
+};
+
 int
 linux_kmap_init(void)
 {
@@ -68,6 +115,9 @@
        KASSERT(linux_kmap_atomic_vaddr != 0);
        KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL));
 
+       mutex_init(&linux_kmap_lock, MUTEX_DEFAULT, IPL_VM);
+       rb_tree_init(&linux_kmap_entries, &linux_kmap_entry_ops);
+
        return 0;
 }
 
@@ -75,6 +125,13 @@
 linux_kmap_fini(void)
 {
 
+       KASSERT(rb_tree_iterate(&linux_kmap_entries, NULL, RB_DIR_RIGHT) ==
+           NULL);
+#if 0                          /* XXX no rb_tree_destroy*/
+       rb_tree_destroy(&linux_kmap_entries);
+#endif
+       mutex_destroy(&linux_kmap_lock);
+
        KASSERT(linux_kmap_atomic_vaddr != 0);
        KASSERT(!pmap_extract(pmap_kernel(), linux_kmap_atomic_vaddr, NULL));
 
@@ -121,16 +178,25 @@
 void *
 kmap(struct page *page)
 {
-       int s;
-
+       const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp);
        const vaddr_t vaddr = uvm_km_alloc(kernel_map, PAGE_SIZE, 0,
            (UVM_KMF_VAONLY | UVM_KMF_WAITVA));
        KASSERT(vaddr != 0);
 
-       s = splvm();
+       struct linux_kmap_entry *const lke = kmem_alloc(sizeof(*lke),
+           KM_SLEEP);
+       lke->lke_paddr = paddr;
+       lke->lke_vaddr = vaddr;
+
+       mutex_spin_enter(&linux_kmap_lock);
+       struct linux_kmap_entry *const collision __unused =
+           rb_tree_insert_node(&linux_kmap_entries, lke);
+       KASSERT(collision == lke);
+       mutex_spin_exit(&linux_kmap_lock);
+
+       const int s = splvm();
 
        KASSERT(!pmap_extract(pmap_kernel(), vaddr, NULL));
-       const paddr_t paddr = uvm_vm_page_to_phys(&page->p_vmp);
        const int prot = (VM_PROT_READ | VM_PROT_WRITE);
        const int flags = 0;
        pmap_kenter_pa(vaddr, paddr, prot, flags);
@@ -142,12 +208,21 @@
 }
 
 void
-kunmap(void *addr)
+kunmap(struct page *page)
 {
-       const vaddr_t vaddr = (vaddr_t)addr;
-       int s;
+       const paddr_t paddr = VM_PAGE_TO_PHYS(&page->p_vmp);
 
-       s = splvm();
+       mutex_spin_enter(&linux_kmap_lock);
+       struct linux_kmap_entry *const lke =
+           rb_tree_find_node(&linux_kmap_entries, &paddr);
+       KASSERT(lke != NULL);
+       rb_tree_remove_node(&linux_kmap_entries, lke);
+       mutex_spin_exit(&linux_kmap_lock);
+
+       const vaddr_t vaddr = lke->lke_vaddr;
+       kmem_free(lke, sizeof(*lke));
+
+       const int s = splvm();
 
        KASSERT(pmap_extract(pmap_kernel(), vaddr, NULL));