summaryrefslogtreecommitdiffstats
path: root/mm/swap_state.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/swap_state.c')
-rw-r--r--mm/swap_state.c106
1 files changed, 71 insertions, 35 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 8c5e7176c..21723c1db 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -25,7 +25,31 @@
* ensure that any mistaken dereferences of this structure cause a
* kernel oops.
*/
-struct inode swapper_inode;
+
+static struct inode_operations swapper_inode_operations = {
+ NULL, /* default file operations */
+ NULL, /* create */
+ NULL, /* lookup */
+ NULL, /* link */
+ NULL, /* unlink */
+ NULL, /* symlink */
+ NULL, /* mkdir */
+ NULL, /* rmdir */
+ NULL, /* mknod */
+ NULL, /* rename */
+ NULL, /* readlink */
+ NULL, /* follow_link */
+ NULL, /* bmap */
+ NULL, /* readpage */
+ NULL, /* writepage */
+ block_flushpage, /* flushpage */
+ NULL, /* truncate */
+ NULL, /* permission */
+ NULL, /* smap */
+ NULL /* revalidate */
+};
+
+struct inode swapper_inode = { i_op: &swapper_inode_operations };
#ifdef SWAP_CACHE_INFO
unsigned long swap_cache_add_total = 0;
@@ -49,20 +73,20 @@ int add_to_swap_cache(struct page *page, unsigned long entry)
#endif
#ifdef DEBUG_SWAP
printk("DebugVM: add_to_swap_cache(%08lx count %d, entry %08lx)\n",
- page_address(page), atomic_read(&page->count), entry);
+ page_address(page), page_count(page), entry);
#endif
if (PageTestandSetSwapCache(page)) {
printk(KERN_ERR "swap_cache: replacing non-empty entry %08lx "
- "on page %08lx\n",
- page->offset, page_address(page));
+ "on page %08lx\n",
+ page->offset, page_address(page));
return 0;
}
if (page->inode) {
printk(KERN_ERR "swap_cache: replacing page-cached entry "
- "on page %08lx\n", page_address(page));
+ "on page %08lx\n", page_address(page));
return 0;
}
- atomic_inc(&page->count);
+ get_page(page);
page->inode = &swapper_inode;
page->offset = entry;
add_page_to_hash_queue(page, &swapper_inode, entry);
@@ -111,7 +135,7 @@ int swap_duplicate(unsigned long entry)
result = 1;
#ifdef DEBUG_SWAP
printk("DebugVM: swap_duplicate(entry %08lx, count now %d)\n",
- entry, p->swap_map[offset]);
+ entry, p->swap_map[offset]);
#endif
out:
return result;
@@ -127,7 +151,7 @@ bad_offset:
bad_unused:
printk(KERN_ERR
"swap_duplicate at %8p: entry %08lx, unused page\n",
- __builtin_return_address(0), entry);
+ __builtin_return_address(0), entry);
goto out;
}
@@ -153,7 +177,7 @@ int swap_count(unsigned long entry)
retval = p->swap_map[offset];
#ifdef DEBUG_SWAP
printk("DebugVM: swap_count(entry %08lx, count %d)\n",
- entry, retval);
+ entry, retval);
#endif
out:
return retval;
@@ -163,16 +187,16 @@ bad_entry:
goto out;
bad_file:
printk(KERN_ERR
- "swap_count: entry %08lx, nonexistent swap file!\n", entry);
+ "swap_count: entry %08lx, nonexistent swap file!\n", entry);
goto out;
bad_offset:
printk(KERN_ERR
- "swap_count: entry %08lx, offset exceeds max!\n", entry);
+ "swap_count: entry %08lx, offset exceeds max!\n", entry);
goto out;
bad_unused:
printk(KERN_ERR
- "swap_count at %8p: entry %08lx, unused page!\n",
- __builtin_return_address(0), entry);
+ "swap_count at %8p: entry %08lx, unused page!\n",
+ __builtin_return_address(0), entry);
goto out;
}
@@ -190,18 +214,17 @@ static inline void remove_from_swap_cache(struct page *page)
#ifdef DEBUG_SWAP
printk("DebugVM: remove_from_swap_cache(%08lx count %d)\n",
- page_address(page), atomic_read(&page->count));
+ page_address(page), page_count(page));
#endif
- PageClearSwapCache (page);
+ PageClearSwapCache(page);
remove_inode_page(page);
}
-
/*
* This must be called only on pages that have
* been verified to be in the swap cache.
*/
-void delete_from_swap_cache(struct page *page)
+void __delete_from_swap_cache(struct page *page)
{
long entry = page->offset;
@@ -210,13 +233,27 @@ void delete_from_swap_cache(struct page *page)
#endif
#ifdef DEBUG_SWAP
printk("DebugVM: delete_from_swap_cache(%08lx count %d, "
- "entry %08lx)\n",
- page_address(page), atomic_read(&page->count), entry);
+ "entry %08lx)\n",
+ page_address(page), page_count(page), entry);
#endif
remove_from_swap_cache (page);
swap_free (entry);
}
+/*
+ * This must be called only on pages that have
+ * been verified to be in the swap cache.
+ */
+void delete_from_swap_cache(struct page *page)
+{
+ lock_page(page);
+
+ __delete_from_swap_cache(page);
+
+ UnlockPage(page);
+ page_cache_release(page);
+}
+
/*
* Perform a free_page(), also freeing any swap cache associated with
* this page if it is the last user of the page.
@@ -229,18 +266,18 @@ void free_page_and_swap_cache(unsigned long addr)
/*
* If we are the only user, then free up the swap cache.
*/
- if (PageSwapCache(page) && !is_page_shared(page)) {
+ if (PageSwapCache(page) && !is_page_shared(page))
delete_from_swap_cache(page);
- }
__free_page(page);
}
/*
- * Lookup a swap entry in the swap cache. We need to be careful about
- * locked pages. A found page will be returned with its refcount
- * incremented.
+ * Lookup a swap entry in the swap cache. A found page will be returned
+ * unlocked and with its refcount incremented - we rely on the kernel
+ * lock getting page table operations atomic even if we drop the page
+ * lock before returning.
*/
struct page * lookup_swap_cache(unsigned long entry)
@@ -251,23 +288,21 @@ struct page * lookup_swap_cache(unsigned long entry)
swap_cache_find_total++;
#endif
while (1) {
- found = find_page(&swapper_inode, entry);
+ found = find_lock_page(&swapper_inode, entry);
if (!found)
return 0;
if (found->inode != &swapper_inode || !PageSwapCache(found))
goto out_bad;
- if (!PageLocked(found)) {
#ifdef SWAP_CACHE_INFO
- swap_cache_find_success++;
+ swap_cache_find_success++;
#endif
- return found;
- }
- __free_page(found);
- __wait_on_page(found);
+ UnlockPage(found);
+ return found;
}
out_bad:
printk (KERN_ERR "VM: Found a non-swapper swap page!\n");
+ UnlockPage(found);
__free_page(found);
return 0;
}
@@ -288,7 +323,7 @@ struct page * read_swap_cache_async(unsigned long entry, int wait)
#ifdef DEBUG_SWAP
printk("DebugVM: read_swap_cache_async entry %08lx%s\n",
- entry, wait ? ", wait" : "");
+ entry, wait ? ", wait" : "");
#endif
/*
* Make sure the swap entry is still in use.
@@ -319,12 +354,12 @@ struct page * read_swap_cache_async(unsigned long entry, int wait)
if (!add_to_swap_cache(new_page, entry))
goto out_free_page;
- set_bit(PG_locked, &new_page->flags);
+ LockPage(new_page);
rw_swap_page(READ, entry, (char *) new_page_addr, wait);
#ifdef DEBUG_SWAP
printk("DebugVM: read_swap_cache_async created "
- "entry %08lx at %p\n",
- entry, (char *) page_address(new_page));
+ "entry %08lx at %p\n",
+ entry, (char *) page_address(new_page));
#endif
return new_page;
@@ -335,3 +370,4 @@ out_free_swap:
out:
return found_page;
}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-19 21:11:17 +0000