mm: strictly nested kmap_atomic()
[linux-2.6.git] / crypto / scatterwalk.c
index 50c9461..41e529a 100644 (file)
  * any later version.
  *
  */
+
+#include <crypto/scatterwalk.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
-#include <asm/bug.h>
-#include <asm/scatterlist.h>
-#include "internal.h"
-#include "scatterwalk.h"
-
-enum km_type crypto_km_types[] = {
-       KM_USER0,
-       KM_USER1,
-       KM_SOFTIRQ0,
-       KM_SOFTIRQ1,
-};
-
-static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
+#include <linux/scatterlist.h>
+
+static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
 {
-       if (out)
-               memcpy(sgdata, buf, nbytes);
-       else
-               memcpy(buf, sgdata, nbytes);
+       void *src = out ? buf : sgdata;
+       void *dst = out ? sgdata : buf;
+
+       memcpy(dst, src, nbytes);
 }
 
 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
 {
-       unsigned int rest_of_page;
-
        walk->sg = sg;
 
-       walk->page = sg->page;
-       walk->len_this_segment = sg->length;
-
        BUG_ON(!sg->length);
 
-       rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
-       walk->len_this_page = min(sg->length, rest_of_page);
        walk->offset = sg->offset;
 }
+EXPORT_SYMBOL_GPL(scatterwalk_start);
 
-void scatterwalk_map(struct scatter_walk *walk, int out)
+void *scatterwalk_map(struct scatter_walk *walk, int out)
 {
-       walk->data = crypto_kmap(walk->page, out) + walk->offset;
-}
-
-static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
-{
-       /* walk->data may be pointing the first byte of the next page;
-          however, we know we transfered at least one byte.  So,
-          walk->data - 1 will be a virtual address in the mapped page. */
-       crypto_kunmap(walk->data - 1, out);
+       return crypto_kmap(scatterwalk_page(walk), out) +
+              offset_in_page(walk->offset);
 }
+EXPORT_SYMBOL_GPL(scatterwalk_map);
 
 static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
                                 unsigned int more)
 {
-       if (out)
-               flush_dcache_page(walk->page);
+       if (out) {
+               struct page *page;
+
+               page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
+               if (!PageSlab(page))
+                       flush_dcache_page(page);
+       }
 
        if (more) {
-               walk->len_this_segment -= walk->len_this_page;
-
-               if (walk->len_this_segment) {
-                       walk->page++;
-                       walk->len_this_page = min(walk->len_this_segment,
-                                                 (unsigned)PAGE_CACHE_SIZE);
-                       walk->offset = 0;
-               }
-               else
-                       scatterwalk_start(walk, sg_next(walk->sg));
+               walk->offset += PAGE_SIZE - 1;
+               walk->offset &= PAGE_MASK;
+               if (walk->offset >= walk->sg->offset + walk->sg->length)
+                       scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
        }
 }
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-       scatterwalk_unmap(walk, out);
-       if (walk->len_this_page == 0 || !more)
+       if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
                scatterwalk_pagedone(walk, out, more);
 }
+EXPORT_SYMBOL_GPL(scatterwalk_done);
 
-/*
- * Do not call this unless the total length of all of the fragments
- * has been verified as multiple of the block size.
- */
-int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
-                          size_t nbytes, int out)
+void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
+                           size_t nbytes, int out)
 {
-       do {
-               memcpy_dir(buf, walk->data, walk->len_this_page, out);
-               buf += walk->len_this_page;
-               nbytes -= walk->len_this_page;
+       for (;;) {
+               unsigned int len_this_page = scatterwalk_pagelen(walk);
+               u8 *vaddr;
+
+               if (len_this_page > nbytes)
+                       len_this_page = nbytes;
+
+               vaddr = scatterwalk_map(walk, out);
+               memcpy_dir(buf, vaddr, len_this_page, out);
+               scatterwalk_unmap(vaddr, out);
+
+               scatterwalk_advance(walk, len_this_page);
+
+               if (nbytes == len_this_page)
+                       break;
+
+               buf += len_this_page;
+               nbytes -= len_this_page;
 
-               scatterwalk_unmap(walk, out);
                scatterwalk_pagedone(walk, out, 1);
-               scatterwalk_map(walk, out);
-       } while (nbytes > walk->len_this_page);
+       }
+}
+EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
+
+void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
+                             unsigned int start, unsigned int nbytes, int out)
+{
+       struct scatter_walk walk;
+       unsigned int offset = 0;
+
+       if (!nbytes)
+               return;
+
+       for (;;) {
+               scatterwalk_start(&walk, sg);
+
+               if (start < offset + sg->length)
+                       break;
+
+               offset += sg->length;
+               sg = scatterwalk_sg_next(sg);
+       }
 
-       memcpy_dir(buf, walk->data, nbytes, out);
-       return nbytes;
+       scatterwalk_advance(&walk, start - offset);
+       scatterwalk_copychunks(buf, &walk, nbytes, out);
+       scatterwalk_done(&walk, out, 0);
 }
+EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);