PM / Hibernate: Snapshot cleanup
Remove support of reads with offset. This means snapshot_read/write_next
now does not accept count parameter. It allows to clean up the functions
and snapshot handle which no longer needs to care about offsets.
/dev/snapshot handler is converted to simple_{read_from,write_to}_buffer
which take care of offsets.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index be861c2..25ce010 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1604,14 +1604,9 @@
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
- * The @count parameter should contain the number of bytes the caller
- * wants to read from the snapshot. It must not be zero.
- *
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
- * location computed by the data_of() macro. The number returned
- * may be smaller than @count, but this only happens if the read would
- * cross a page boundary otherwise.
+ * location computed by the data_of() macro.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
@@ -1619,7 +1614,7 @@
* any more.
*/
-int snapshot_read_next(struct snapshot_handle *handle, size_t count)
+int snapshot_read_next(struct snapshot_handle *handle)
{
if (handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
@@ -1630,7 +1625,7 @@
if (!buffer)
return -ENOMEM;
}
- if (!handle->offset) {
+ if (!handle->cur) {
int error;
error = init_header((struct swsusp_info *)buffer);
@@ -1639,42 +1634,30 @@
handle->buffer = buffer;
memory_bm_position_reset(&orig_bm);
memory_bm_position_reset(©_bm);
- }
- if (handle->prev < handle->cur) {
- if (handle->cur <= nr_meta_pages) {
- memset(buffer, 0, PAGE_SIZE);
- pack_pfns(buffer, &orig_bm);
- } else {
- struct page *page;
-
- page = pfn_to_page(memory_bm_next_pfn(©_bm));
- if (PageHighMem(page)) {
- /* Highmem pages are copied to the buffer,
- * because we can't return with a kmapped
- * highmem page (we may not be called again).
- */
- void *kaddr;
-
- kaddr = kmap_atomic(page, KM_USER0);
- memcpy(buffer, kaddr, PAGE_SIZE);
- kunmap_atomic(kaddr, KM_USER0);
- handle->buffer = buffer;
- } else {
- handle->buffer = page_address(page);
- }
- }
- handle->prev = handle->cur;
- }
- handle->buf_offset = handle->cur_offset;
- if (handle->cur_offset + count >= PAGE_SIZE) {
- count = PAGE_SIZE - handle->cur_offset;
- handle->cur_offset = 0;
- handle->cur++;
+ } else if (handle->cur <= nr_meta_pages) {
+ memset(buffer, 0, PAGE_SIZE);
+ pack_pfns(buffer, &orig_bm);
} else {
- handle->cur_offset += count;
+ struct page *page;
+
+ page = pfn_to_page(memory_bm_next_pfn(©_bm));
+ if (PageHighMem(page)) {
+ /* Highmem pages are copied to the buffer,
+ * because we can't return with a kmapped
+ * highmem page (we may not be called again).
+ */
+ void *kaddr;
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ memcpy(buffer, kaddr, PAGE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ handle->buffer = buffer;
+ } else {
+ handle->buffer = page_address(page);
+ }
}
- handle->offset += count;
- return count;
+ handle->cur++;
+ return PAGE_SIZE;
}
/**
@@ -2133,14 +2116,9 @@
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
- * The @count parameter should contain the number of bytes the caller
- * wants to write to the image. It must not be zero.
- *
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
- * location computed by the data_of() macro. The number returned
- * may be smaller than @count, but this only happens if the write would
- * cross a page boundary otherwise.
+ * location computed by the data_of() macro.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
@@ -2148,16 +2126,18 @@
* any more.
*/
-int snapshot_write_next(struct snapshot_handle *handle, size_t count)
+int snapshot_write_next(struct snapshot_handle *handle)
{
static struct chain_allocator ca;
int error = 0;
/* Check if we have already loaded the entire image */
- if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
+ if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
- if (handle->offset == 0) {
+ handle->sync_read = 1;
+
+ if (!handle->cur) {
if (!buffer)
/* This makes the buffer be freed by swsusp_free() */
buffer = get_image_page(GFP_ATOMIC, PG_ANY);
@@ -2166,56 +2146,43 @@
return -ENOMEM;
handle->buffer = buffer;
- }
- handle->sync_read = 1;
- if (handle->prev < handle->cur) {
- if (handle->prev == 0) {
- error = load_header(buffer);
+ } else if (handle->cur == 1) {
+ error = load_header(buffer);
+ if (error)
+ return error;
+
+ error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
+ if (error)
+ return error;
+
+ } else if (handle->cur <= nr_meta_pages + 1) {
+ error = unpack_orig_pfns(buffer, ©_bm);
+ if (error)
+ return error;
+
+ if (handle->cur == nr_meta_pages + 1) {
+ error = prepare_image(&orig_bm, ©_bm);
if (error)
return error;
- error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
- if (error)
- return error;
-
- } else if (handle->prev <= nr_meta_pages) {
- error = unpack_orig_pfns(buffer, ©_bm);
- if (error)
- return error;
-
- if (handle->prev == nr_meta_pages) {
- error = prepare_image(&orig_bm, ©_bm);
- if (error)
- return error;
-
- chain_init(&ca, GFP_ATOMIC, PG_SAFE);
- memory_bm_position_reset(&orig_bm);
- restore_pblist = NULL;
- handle->buffer = get_buffer(&orig_bm, &ca);
- handle->sync_read = 0;
- if (IS_ERR(handle->buffer))
- return PTR_ERR(handle->buffer);
- }
- } else {
- copy_last_highmem_page();
+ chain_init(&ca, GFP_ATOMIC, PG_SAFE);
+ memory_bm_position_reset(&orig_bm);
+ restore_pblist = NULL;
handle->buffer = get_buffer(&orig_bm, &ca);
+ handle->sync_read = 0;
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
- if (handle->buffer != buffer)
- handle->sync_read = 0;
}
- handle->prev = handle->cur;
- }
- handle->buf_offset = handle->cur_offset;
- if (handle->cur_offset + count >= PAGE_SIZE) {
- count = PAGE_SIZE - handle->cur_offset;
- handle->cur_offset = 0;
- handle->cur++;
} else {
- handle->cur_offset += count;
+ copy_last_highmem_page();
+ handle->buffer = get_buffer(&orig_bm, &ca);
+ if (IS_ERR(handle->buffer))
+ return PTR_ERR(handle->buffer);
+ if (handle->buffer != buffer)
+ handle->sync_read = 0;
}
- handle->offset += count;
- return count;
+ handle->cur++;
+ return PAGE_SIZE;
}
/**
@@ -2230,7 +2197,7 @@
{
copy_last_highmem_page();
/* Free only if we have loaded the image entirely */
- if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
+ if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
free_highmem_data();
}