diff options
author | Rafael J. Wysocki <rjw@sisk.pl> | 2006-09-26 02:32:46 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-26 11:48:58 -0400 |
commit | fb13a28b0f5ada60861868c4fa48a12bd0cb8dea (patch) | |
tree | e0a4611621f2d5abc94f0b0ea5a2c41f2962e5e1 | |
parent | ae83c5eef59ffe6eb61110b8c8fd1ea3e0881712 (diff) |
[PATCH] swsusp: struct snapshot_handle cleanup
Add comments describing struct snapshot_handle and its members, change the
confusing name of its member 'page' to 'cur'.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r-- | kernel/power/power.h | 64 | ||||
-rw-r--r-- | kernel/power/snapshot.c | 40 |
2 files changed, 76 insertions, 28 deletions
diff --git a/kernel/power/power.h b/kernel/power/power.h index 59ce712f082d..1cefcf87a694 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h | |||
@@ -50,17 +50,65 @@ extern asmlinkage int swsusp_arch_resume(void); | |||
50 | 50 | ||
51 | extern unsigned int count_data_pages(void); | 51 | extern unsigned int count_data_pages(void); |
52 | 52 | ||
53 | /** | ||
54 | * Auxiliary structure used for reading the snapshot image data and | ||
55 | * metadata from and writing them to the list of page backup entries | ||
56 | * (PBEs) which is the main data structure of swsusp. | ||
57 | * | ||
58 | * Using struct snapshot_handle we can transfer the image, including its | ||
59 | * metadata, as a continuous sequence of bytes with the help of | ||
60 | * snapshot_read_next() and snapshot_write_next(). | ||
61 | * | ||
62 | * The code that writes the image to a storage or transfers it to | ||
63 | * the user land is required to use snapshot_read_next() for this | ||
64 | * purpose and it should not make any assumptions regarding the internal | ||
65 | * structure of the image. Similarly, the code that reads the image from | ||
66 | * a storage or transfers it from the user land is required to use | ||
67 | * snapshot_write_next(). | ||
68 | * | ||
69 | * This may allow us to change the internal structure of the image | ||
70 | * in the future with considerably less effort. | ||
71 | */ | ||
72 | |||
53 | struct snapshot_handle { | 73 | struct snapshot_handle { |
54 | loff_t offset; | 74 | loff_t offset; /* number of the last byte ready for reading |
55 | unsigned int page; | 75 | * or writing in the sequence |
56 | unsigned int page_offset; | 76 | */ |
57 | unsigned int prev; | 77 | unsigned int cur; /* number of the block of PAGE_SIZE bytes the |
58 | struct pbe *pbe, *last_pbe; | 78 | * next operation will refer to (ie. current) |
59 | void *buffer; | 79 | */ |
60 | unsigned int buf_offset; | 80 | unsigned int cur_offset; /* offset with respect to the current |
61 | int sync_read; | 81 | * block (for the next operation) |
82 | */ | ||
83 | unsigned int prev; /* number of the block of PAGE_SIZE bytes that | ||
84 | * was the current one previously | ||
85 | */ | ||
86 | struct pbe *pbe; /* PBE that corresponds to 'buffer' */ | ||
87 | struct pbe *last_pbe; /* When the image is restored (eg. read | ||
88 | * from disk) we can store some image | ||
89 | * data directly in the page frames | ||
90 | * in which they were before suspend. | ||
91 | * In such a case the PBEs that | ||
92 | * correspond to them will be unused. | ||
93 | * This is the last PBE, so far, that | ||
94 | * does not correspond to such data. | ||
95 | */ | ||
96 | void *buffer; /* address of the block to read from | ||
97 | * or write to | ||
98 | */ | ||
99 | unsigned int buf_offset; /* location to read from or write to, | ||
100 | * given as a displacement from 'buffer' | ||
101 | */ | ||
102 | int sync_read; /* Set to one to notify the caller of | ||
103 | * snapshot_write_next() that it may | ||
104 | * need to call wait_on_bio_chain() | ||
105 | */ | ||
62 | }; | 106 | }; |
63 | 107 | ||
108 | /* This macro returns the address from/to which the caller of | ||
109 | * snapshot_read_next()/snapshot_write_next() is allowed to | ||
110 | * read/write data after the function returns | ||
111 | */ | ||
64 | #define data_of(handle) ((handle).buffer + (handle).buf_offset) | 112 | #define data_of(handle) ((handle).buffer + (handle).buf_offset) |
65 | 113 | ||
66 | extern int snapshot_read_next(struct snapshot_handle *handle, size_t count); | 114 | extern int snapshot_read_next(struct snapshot_handle *handle, size_t count); |
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 979096c27773..81fe8de9e604 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c | |||
@@ -555,7 +555,7 @@ static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pb | |||
555 | 555 | ||
556 | int snapshot_read_next(struct snapshot_handle *handle, size_t count) | 556 | int snapshot_read_next(struct snapshot_handle *handle, size_t count) |
557 | { | 557 | { |
558 | if (handle->page > nr_meta_pages + nr_copy_pages) | 558 | if (handle->cur > nr_meta_pages + nr_copy_pages) |
559 | return 0; | 559 | return 0; |
560 | if (!buffer) { | 560 | if (!buffer) { |
561 | /* This makes the buffer be freed by swsusp_free() */ | 561 | /* This makes the buffer be freed by swsusp_free() */ |
@@ -568,8 +568,8 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count) | |||
568 | handle->buffer = buffer; | 568 | handle->buffer = buffer; |
569 | handle->pbe = pagedir_nosave; | 569 | handle->pbe = pagedir_nosave; |
570 | } | 570 | } |
571 | if (handle->prev < handle->page) { | 571 | if (handle->prev < handle->cur) { |
572 | if (handle->page <= nr_meta_pages) { | 572 | if (handle->cur <= nr_meta_pages) { |
573 | handle->pbe = pack_orig_addresses(buffer, handle->pbe); | 573 | handle->pbe = pack_orig_addresses(buffer, handle->pbe); |
574 | if (!handle->pbe) | 574 | if (!handle->pbe) |
575 | handle->pbe = pagedir_nosave; | 575 | handle->pbe = pagedir_nosave; |
@@ -577,15 +577,15 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count) | |||
577 | handle->buffer = (void *)handle->pbe->address; | 577 | handle->buffer = (void *)handle->pbe->address; |
578 | handle->pbe = handle->pbe->next; | 578 | handle->pbe = handle->pbe->next; |
579 | } | 579 | } |
580 | handle->prev = handle->page; | 580 | handle->prev = handle->cur; |
581 | } | 581 | } |
582 | handle->buf_offset = handle->page_offset; | 582 | handle->buf_offset = handle->cur_offset; |
583 | if (handle->page_offset + count >= PAGE_SIZE) { | 583 | if (handle->cur_offset + count >= PAGE_SIZE) { |
584 | count = PAGE_SIZE - handle->page_offset; | 584 | count = PAGE_SIZE - handle->cur_offset; |
585 | handle->page_offset = 0; | 585 | handle->cur_offset = 0; |
586 | handle->page++; | 586 | handle->cur++; |
587 | } else { | 587 | } else { |
588 | handle->page_offset += count; | 588 | handle->cur_offset += count; |
589 | } | 589 | } |
590 | handle->offset += count; | 590 | handle->offset += count; |
591 | return count; | 591 | return count; |
@@ -820,7 +820,7 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) | |||
820 | { | 820 | { |
821 | int error = 0; | 821 | int error = 0; |
822 | 822 | ||
823 | if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages) | 823 | if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) |
824 | return 0; | 824 | return 0; |
825 | if (!buffer) { | 825 | if (!buffer) { |
826 | /* This makes the buffer be freed by swsusp_free() */ | 826 | /* This makes the buffer be freed by swsusp_free() */ |
@@ -831,7 +831,7 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) | |||
831 | if (!handle->offset) | 831 | if (!handle->offset) |
832 | handle->buffer = buffer; | 832 | handle->buffer = buffer; |
833 | handle->sync_read = 1; | 833 | handle->sync_read = 1; |
834 | if (handle->prev < handle->page) { | 834 | if (handle->prev < handle->cur) { |
835 | if (!handle->prev) { | 835 | if (!handle->prev) { |
836 | error = load_header(handle, | 836 | error = load_header(handle, |
837 | (struct swsusp_info *)buffer); | 837 | (struct swsusp_info *)buffer); |
@@ -854,15 +854,15 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) | |||
854 | handle->buffer = get_buffer(handle); | 854 | handle->buffer = get_buffer(handle); |
855 | handle->sync_read = 0; | 855 | handle->sync_read = 0; |
856 | } | 856 | } |
857 | handle->prev = handle->page; | 857 | handle->prev = handle->cur; |
858 | } | 858 | } |
859 | handle->buf_offset = handle->page_offset; | 859 | handle->buf_offset = handle->cur_offset; |
860 | if (handle->page_offset + count >= PAGE_SIZE) { | 860 | if (handle->cur_offset + count >= PAGE_SIZE) { |
861 | count = PAGE_SIZE - handle->page_offset; | 861 | count = PAGE_SIZE - handle->cur_offset; |
862 | handle->page_offset = 0; | 862 | handle->cur_offset = 0; |
863 | handle->page++; | 863 | handle->cur++; |
864 | } else { | 864 | } else { |
865 | handle->page_offset += count; | 865 | handle->cur_offset += count; |
866 | } | 866 | } |
867 | handle->offset += count; | 867 | handle->offset += count; |
868 | return count; | 868 | return count; |
@@ -871,5 +871,5 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) | |||
871 | int snapshot_image_loaded(struct snapshot_handle *handle) | 871 | int snapshot_image_loaded(struct snapshot_handle *handle) |
872 | { | 872 | { |
873 | return !(!handle->pbe || handle->pbe->next || !nr_copy_pages || | 873 | return !(!handle->pbe || handle->pbe->next || !nr_copy_pages || |
874 | handle->page <= nr_meta_pages + nr_copy_pages); | 874 | handle->cur <= nr_meta_pages + nr_copy_pages); |
875 | } | 875 | } |