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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>
This commit is contained in:
Jiri Slaby 2010-05-01 23:52:02 +02:00 committed by Rafael J. Wysocki
parent 6a727b43be
commit d3c1b24c50
4 changed files with 92 additions and 124 deletions
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18
kernel/power/power.h
View File

@ -97,24 +97,12 @@ extern int hibernate_preallocate_memory(void);
*/
struct snapshot_handle {
loff_t offset; /* number of the last byte ready for reading
* or writing in the sequence
*/
unsigned int cur; /* number of the block of PAGE_SIZE bytes the
* next operation will refer to (ie. current)
*/
unsigned int cur_offset; /* offset with respect to the current
* block (for the next operation)
*/
unsigned int prev; /* number of the block of PAGE_SIZE bytes that
* was the current one previously
*/
void *buffer; /* address of the block to read from
* or write to
*/
unsigned int buf_offset; /* location to read from or write to,
* given as a displacement from 'buffer'
*/
int sync_read; /* Set to one to notify the caller of
* snapshot_write_next() that it may
* need to call wait_on_bio_chain()
@ -125,12 +113,12 @@ struct snapshot_handle {
* snapshot_read_next()/snapshot_write_next() is allowed to
* read/write data after the function returns
*/
#define data_of(handle) ((handle).buffer + (handle).buf_offset)
#define data_of(handle) ((handle).buffer)
extern unsigned int snapshot_additional_pages(struct zone *zone);
extern unsigned long snapshot_get_image_size(void);
extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
extern int snapshot_read_next(struct snapshot_handle *handle);
extern int snapshot_write_next(struct snapshot_handle *handle);
extern void snapshot_write_finalize(struct snapshot_handle *handle);
extern int snapshot_image_loaded(struct snapshot_handle *handle);

153
kernel/power/snapshot.c
View File

@ -1604,14 +1604,9 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
* 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 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
* 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 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
if (!buffer)
return -ENOMEM;
}
if (!handle->offset) {
if (!handle->cur) {
int error;
error = init_header((struct swsusp_info *)buffer);
@ -1639,42 +1634,30 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
handle->buffer = buffer;
memory_bm_position_reset(&orig_bm);
memory_bm_position_reset(&copy_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(&copy_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(&copy_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 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
* 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 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
* 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 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
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(&copy_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
} else if (handle->cur <= nr_meta_pages + 1) {
error = unpack_orig_pfns(buffer, &copy_bm);
if (error)
return error;
if (handle->cur == nr_meta_pages + 1) {
error = prepare_image(&orig_bm, &copy_bm);
if (error)
return error;
error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
} else if (handle->prev <= nr_meta_pages) {
error = unpack_orig_pfns(buffer, &copy_bm);
if (error)
return error;
if (handle->prev == nr_meta_pages) {
error = prepare_image(&orig_bm, &copy_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 @@ void snapshot_write_finalize(struct snapshot_handle *handle)
{
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();
}

8
kernel/power/swap.c
View File

@ -431,7 +431,7 @@ static int save_image(struct swap_map_handle *handle,
bio = NULL;
do_gettimeofday(&start);
while (1) {
ret = snapshot_read_next(snapshot, PAGE_SIZE);
ret = snapshot_read_next(snapshot);
if (ret <= 0)
break;
ret = swap_write_page(handle, data_of(*snapshot), &bio);
@ -492,7 +492,7 @@ int swsusp_write(unsigned int flags)
return error;
}
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_read_next(&snapshot, PAGE_SIZE);
error = snapshot_read_next(&snapshot);
if (error < PAGE_SIZE) {
if (error >= 0)
error = -EFAULT;
@ -615,7 +615,7 @@ static int load_image(struct swap_map_handle *handle,
bio = NULL;
do_gettimeofday(&start);
for ( ; ; ) {
error = snapshot_write_next(snapshot, PAGE_SIZE);
error = snapshot_write_next(snapshot);
if (error <= 0)
break;
error = swap_read_page(handle, data_of(*snapshot), &bio);
@ -660,7 +660,7 @@ int swsusp_read(unsigned int *flags_p)
*flags_p = swsusp_header->flags;
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_write_next(&snapshot, PAGE_SIZE);
error = snapshot_write_next(&snapshot);
if (error < PAGE_SIZE)
return error < 0 ? error : -EFAULT;
header = (struct swsusp_info *)data_of(snapshot);

37
kernel/power/user.c
View File

@ -151,6 +151,7 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
@ -159,14 +160,19 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
res = -ENODATA;
goto Unlock;
}
res = snapshot_read_next(&data->handle, count);
if (res > 0) {
if (copy_to_user(buf, data_of(data->handle), res))
res = -EFAULT;
else
*offp = data->handle.offset;
if (!pg_offp) { /* on page boundary? */
res = snapshot_read_next(&data->handle);
if (res <= 0)
goto Unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_read_from_buffer(buf, count, &pg_offp,
data_of(data->handle), res);
if (res > 0)
*offp += res;
Unlock:
mutex_unlock(&pm_mutex);
@ -178,18 +184,25 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
data = filp->private_data;
res = snapshot_write_next(&data->handle, count);
if (res > 0) {
if (copy_from_user(data_of(data->handle), buf, res))
res = -EFAULT;
else
*offp = data->handle.offset;
if (!pg_offp) {
res = snapshot_write_next(&data->handle);
if (res <= 0)
goto unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
buf, count);
if (res > 0)
*offp += res;
unlock:
mutex_unlock(&pm_mutex);
return res;