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swapfile: remove v0 SWAP-SPACE message
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The kernel has not supported v0 SWAP-SPACE since 2.5.22: I think we can
now safely drop its "version 0 swap is no longer supported" message - just
say "Unable to find swap-space signature" as usual.  This removes one
level of indentation from a stretch of sys_swapon().

I'd have liked to be specific, saying "Unable to find SWAPSPACE2
signature", but it's just too confusing that the version 1 signature shows
the number 2.

Irrelevant nearby cleanup: kmap(page) already gives page_address(page).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Hugh Dickins authored and Linus Torvalds committed Jan 6, 2009
1 parent 886bb7e commit 81e3397
Showing 1 changed file with 65 additions and 81 deletions.
146 changes: 65 additions & 81 deletions mm/swapfile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1456,7 +1456,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
int i, prev;
int error;
union swap_header *swap_header = NULL;
int swap_header_version;
unsigned int nr_good_pages = 0;
int nr_extents = 0;
sector_t span;
Expand Down Expand Up @@ -1553,101 +1552,86 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
error = PTR_ERR(page);
goto bad_swap;
}
kmap(page);
swap_header = page_address(page);
swap_header = kmap(page);

if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10))
swap_header_version = 1;
else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10))
swap_header_version = 2;
else {
if (memcmp("SWAPSPACE2", swap_header->magic.magic, 10)) {
printk(KERN_ERR "Unable to find swap-space signature\n");
error = -EINVAL;
goto bad_swap;
}

switch (swap_header_version) {
case 1:
printk(KERN_ERR "version 0 swap is no longer supported. "
"Use mkswap -v1 %s\n", name);
/* swap partition endianess hack... */
if (swab32(swap_header->info.version) == 1) {
swab32s(&swap_header->info.version);
swab32s(&swap_header->info.last_page);
swab32s(&swap_header->info.nr_badpages);
for (i = 0; i < swap_header->info.nr_badpages; i++)
swab32s(&swap_header->info.badpages[i]);
}
/* Check the swap header's sub-version */
if (swap_header->info.version != 1) {
printk(KERN_WARNING
"Unable to handle swap header version %d\n",
swap_header->info.version);
error = -EINVAL;
goto bad_swap;
case 2:
/* swap partition endianess hack... */
if (swab32(swap_header->info.version) == 1) {
swab32s(&swap_header->info.version);
swab32s(&swap_header->info.last_page);
swab32s(&swap_header->info.nr_badpages);
for (i = 0; i < swap_header->info.nr_badpages; i++)
swab32s(&swap_header->info.badpages[i]);
}
/* Check the swap header's sub-version and the size of
the swap file and bad block lists */
if (swap_header->info.version != 1) {
printk(KERN_WARNING
"Unable to handle swap header version %d\n",
swap_header->info.version);
error = -EINVAL;
goto bad_swap;
}
}

p->lowest_bit = 1;
p->cluster_next = 1;
p->lowest_bit = 1;
p->cluster_next = 1;

/*
* Find out how many pages are allowed for a single swap
* device. There are two limiting factors: 1) the number of
* bits for the swap offset in the swp_entry_t type and
* 2) the number of bits in the a swap pte as defined by
* the different architectures. In order to find the
* largest possible bit mask a swap entry with swap type 0
* and swap offset ~0UL is created, encoded to a swap pte,
* decoded to a swp_entry_t again and finally the swap
* offset is extracted. This will mask all the bits from
* the initial ~0UL mask that can't be encoded in either
* the swp_entry_t or the architecture definition of a
* swap pte.
*/
maxpages = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0,~0UL)))) - 1;
if (maxpages > swap_header->info.last_page)
maxpages = swap_header->info.last_page;
p->highest_bit = maxpages - 1;
/*
* Find out how many pages are allowed for a single swap
* device. There are two limiting factors: 1) the number of
* bits for the swap offset in the swp_entry_t type and
* 2) the number of bits in the a swap pte as defined by
* the different architectures. In order to find the
* largest possible bit mask a swap entry with swap type 0
* and swap offset ~0UL is created, encoded to a swap pte,
* decoded to a swp_entry_t again and finally the swap
* offset is extracted. This will mask all the bits from
* the initial ~0UL mask that can't be encoded in either
* the swp_entry_t or the architecture definition of a
* swap pte.
*/
maxpages = swp_offset(pte_to_swp_entry(
swp_entry_to_pte(swp_entry(0, ~0UL)))) - 1;
if (maxpages > swap_header->info.last_page)
maxpages = swap_header->info.last_page;
p->highest_bit = maxpages - 1;

error = -EINVAL;
if (!maxpages)
goto bad_swap;
if (swapfilepages && maxpages > swapfilepages) {
printk(KERN_WARNING
"Swap area shorter than signature indicates\n");
goto bad_swap;
}
if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode))
goto bad_swap;
if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
goto bad_swap;
error = -EINVAL;
if (!maxpages)
goto bad_swap;
if (swapfilepages && maxpages > swapfilepages) {
printk(KERN_WARNING
"Swap area shorter than signature indicates\n");
goto bad_swap;
}
if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode))
goto bad_swap;
if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
goto bad_swap;

/* OK, set up the swap map and apply the bad block list */
swap_map = vmalloc(maxpages * sizeof(short));
if (!swap_map) {
error = -ENOMEM;
goto bad_swap;
}
/* OK, set up the swap map and apply the bad block list */
swap_map = vmalloc(maxpages * sizeof(short));
if (!swap_map) {
error = -ENOMEM;
goto bad_swap;
}

error = 0;
memset(swap_map, 0, maxpages * sizeof(short));
for (i = 0; i < swap_header->info.nr_badpages; i++) {
int page_nr = swap_header->info.badpages[i];
if (page_nr <= 0 || page_nr >= swap_header->info.last_page)
error = -EINVAL;
else
swap_map[page_nr] = SWAP_MAP_BAD;
}
nr_good_pages = swap_header->info.last_page -
swap_header->info.nr_badpages -
1 /* header page */;
if (error)
memset(swap_map, 0, maxpages * sizeof(short));
for (i = 0; i < swap_header->info.nr_badpages; i++) {
int page_nr = swap_header->info.badpages[i];
if (page_nr <= 0 || page_nr >= swap_header->info.last_page) {
error = -EINVAL;
goto bad_swap;
}
swap_map[page_nr] = SWAP_MAP_BAD;
}
nr_good_pages = swap_header->info.last_page -
swap_header->info.nr_badpages -
1 /* header page */;

if (nr_good_pages) {
swap_map[0] = SWAP_MAP_BAD;
Expand Down

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