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-rw-r--r--fs/btrfs/zlib.c253
1 files changed, 50 insertions, 203 deletions
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index b01558661e3b..9a3e693917f2 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -32,15 +32,6 @@
#include <linux/bio.h>
#include "compression.h"
-/* Plan: call deflate() with avail_in == *sourcelen,
- avail_out = *dstlen - 12 and flush == Z_FINISH.
- If it doesn't manage to finish, call it again with
- avail_in == 0 and avail_out set to the remaining 12
- bytes for it to clean up.
- Q: Is 12 bytes sufficient?
-*/
-#define STREAM_END_SPACE 12
-
struct workspace {
z_stream inf_strm;
z_stream def_strm;
@@ -48,155 +39,51 @@ struct workspace {
struct list_head list;
};
-static LIST_HEAD(idle_workspace);
-static DEFINE_SPINLOCK(workspace_lock);
-static unsigned long num_workspace;
-static atomic_t alloc_workspace = ATOMIC_INIT(0);
-static DECLARE_WAIT_QUEUE_HEAD(workspace_wait);
+static void zlib_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
-/*
- * this finds an available zlib workspace or allocates a new one
- * NULL or an ERR_PTR is returned if things go bad.
- */
-static struct workspace *find_zlib_workspace(void)
+ vfree(workspace->def_strm.workspace);
+ vfree(workspace->inf_strm.workspace);
+ kfree(workspace->buf);
+ kfree(workspace);
+}
+
+static struct list_head *zlib_alloc_workspace(void)
{
struct workspace *workspace;
- int ret;
- int cpus = num_online_cpus();
-
-again:
- spin_lock(&workspace_lock);
- if (!list_empty(&idle_workspace)) {
- workspace = list_entry(idle_workspace.next, struct workspace,
- list);
- list_del(&workspace->list);
- num_workspace--;
- spin_unlock(&workspace_lock);
- return workspace;
-
- }
- if (atomic_read(&alloc_workspace) > cpus) {
- DEFINE_WAIT(wait);
-
- spin_unlock(&workspace_lock);
- prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
- if (atomic_read(&alloc_workspace) > cpus && !num_workspace)
- schedule();
- finish_wait(&workspace_wait, &wait);
- goto again;
- }
- atomic_inc(&alloc_workspace);
- spin_unlock(&workspace_lock);
workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
- if (!workspace) {
- ret = -ENOMEM;
- goto fail;
- }
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
- if (!workspace->def_strm.workspace) {
- ret = -ENOMEM;
- goto fail;
- }
workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
- if (!workspace->inf_strm.workspace) {
- ret = -ENOMEM;
- goto fail_inflate;
- }
workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
- if (!workspace->buf) {
- ret = -ENOMEM;
- goto fail_kmalloc;
- }
- return workspace;
-
-fail_kmalloc:
- vfree(workspace->inf_strm.workspace);
-fail_inflate:
- vfree(workspace->def_strm.workspace);
-fail:
- kfree(workspace);
- atomic_dec(&alloc_workspace);
- wake_up(&workspace_wait);
- return ERR_PTR(ret);
-}
-
-/*
- * put a workspace struct back on the list or free it if we have enough
- * idle ones sitting around
- */
-static int free_workspace(struct workspace *workspace)
-{
- spin_lock(&workspace_lock);
- if (num_workspace < num_online_cpus()) {
- list_add_tail(&workspace->list, &idle_workspace);
- num_workspace++;
- spin_unlock(&workspace_lock);
- if (waitqueue_active(&workspace_wait))
- wake_up(&workspace_wait);
- return 0;
- }
- spin_unlock(&workspace_lock);
- vfree(workspace->def_strm.workspace);
- vfree(workspace->inf_strm.workspace);
- kfree(workspace->buf);
- kfree(workspace);
+ if (!workspace->def_strm.workspace ||
+ !workspace->inf_strm.workspace || !workspace->buf)
+ goto fail;
- atomic_dec(&alloc_workspace);
- if (waitqueue_active(&workspace_wait))
- wake_up(&workspace_wait);
- return 0;
-}
+ INIT_LIST_HEAD(&workspace->list);
-/*
- * cleanup function for module exit
- */
-static void free_workspaces(void)
-{
- struct workspace *workspace;
- while (!list_empty(&idle_workspace)) {
- workspace = list_entry(idle_workspace.next, struct workspace,
- list);
- list_del(&workspace->list);
- vfree(workspace->def_strm.workspace);
- vfree(workspace->inf_strm.workspace);
- kfree(workspace->buf);
- kfree(workspace);
- atomic_dec(&alloc_workspace);
- }
+ return &workspace->list;
+fail:
+ zlib_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
}
-/*
- * given an address space and start/len, compress the bytes.
- *
- * pages are allocated to hold the compressed result and stored
- * in 'pages'
- *
- * out_pages is used to return the number of pages allocated. There
- * may be pages allocated even if we return an error
- *
- * total_in is used to return the number of bytes actually read. It
- * may be smaller then len if we had to exit early because we
- * ran out of room in the pages array or because we cross the
- * max_out threshold.
- *
- * total_out is used to return the total number of compressed bytes
- *
- * max_out tells us the max number of bytes that we're allowed to
- * stuff into pages
- */
-int btrfs_zlib_compress_pages(struct address_space *mapping,
- u64 start, unsigned long len,
- struct page **pages,
- unsigned long nr_dest_pages,
- unsigned long *out_pages,
- unsigned long *total_in,
- unsigned long *total_out,
- unsigned long max_out)
+static int zlib_compress_pages(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_out)
{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret;
- struct workspace *workspace;
char *data_in;
char *cpage_out;
int nr_pages = 0;
@@ -208,10 +95,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping,
*total_out = 0;
*total_in = 0;
- workspace = find_zlib_workspace();
- if (IS_ERR(workspace))
- return -1;
-
if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
printk(KERN_WARNING "deflateInit failed\n");
ret = -1;
@@ -325,35 +208,18 @@ out:
kunmap(in_page);
page_cache_release(in_page);
}
- free_workspace(workspace);
return ret;
}
-/*
- * pages_in is an array of pages with compressed data.
- *
- * disk_start is the starting logical offset of this array in the file
- *
- * bvec is a bio_vec of pages from the file that we want to decompress into
- *
- * vcnt is the count of pages in the biovec
- *
- * srclen is the number of bytes in pages_in
- *
- * The basic idea is that we have a bio that was created by readpages.
- * The pages in the bio are for the uncompressed data, and they may not
- * be contiguous. They all correspond to the range of bytes covered by
- * the compressed extent.
- */
-int btrfs_zlib_decompress_biovec(struct page **pages_in,
- u64 disk_start,
- struct bio_vec *bvec,
- int vcnt,
- size_t srclen)
+static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
+ u64 disk_start,
+ struct bio_vec *bvec,
+ int vcnt,
+ size_t srclen)
{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0;
int wbits = MAX_WBITS;
- struct workspace *workspace;
char *data_in;
size_t total_out = 0;
unsigned long page_bytes_left;
@@ -371,10 +237,6 @@ int btrfs_zlib_decompress_biovec(struct page **pages_in,
unsigned long current_buf_start;
char *kaddr;
- workspace = find_zlib_workspace();
- if (IS_ERR(workspace))
- return -ENOMEM;
-
data_in = kmap(pages_in[page_in_index]);
workspace->inf_strm.next_in = data_in;
workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
@@ -400,8 +262,7 @@ int btrfs_zlib_decompress_biovec(struct page **pages_in,
if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
printk(KERN_WARNING "inflateInit failed\n");
- ret = -1;
- goto out;
+ return -1;
}
while (workspace->inf_strm.total_in < srclen) {
ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
@@ -527,35 +388,21 @@ done:
zlib_inflateEnd(&workspace->inf_strm);
if (data_in)
kunmap(pages_in[page_in_index]);
-out:
- free_workspace(workspace);
return ret;
}
-/*
- * a less complex decompression routine. Our compressed data fits in a
- * single page, and we want to read a single page out of it.
- * start_byte tells us the offset into the compressed data we're interested in
- */
-int btrfs_zlib_decompress(unsigned char *data_in,
- struct page *dest_page,
- unsigned long start_byte,
- size_t srclen, size_t destlen)
+static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
+ struct page *dest_page,
+ unsigned long start_byte,
+ size_t srclen, size_t destlen)
{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0;
int wbits = MAX_WBITS;
- struct workspace *workspace;
unsigned long bytes_left = destlen;
unsigned long total_out = 0;
char *kaddr;
- if (destlen > PAGE_CACHE_SIZE)
- return -ENOMEM;
-
- workspace = find_zlib_workspace();
- if (IS_ERR(workspace))
- return -ENOMEM;
-
workspace->inf_strm.next_in = data_in;
workspace->inf_strm.avail_in = srclen;
workspace->inf_strm.total_in = 0;
@@ -576,8 +423,7 @@ int btrfs_zlib_decompress(unsigned char *data_in,
if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
printk(KERN_WARNING "inflateInit failed\n");
- ret = -1;
- goto out;
+ return -1;
}
while (bytes_left > 0) {
@@ -627,12 +473,13 @@ next:
ret = 0;
zlib_inflateEnd(&workspace->inf_strm);
-out:
- free_workspace(workspace);
return ret;
}
-void btrfs_zlib_exit(void)
-{
- free_workspaces();
-}
+struct btrfs_compress_op btrfs_zlib_compress = {
+ .alloc_workspace = zlib_alloc_workspace,
+ .free_workspace = zlib_free_workspace,
+ .compress_pages = zlib_compress_pages,
+ .decompress_biovec = zlib_decompress_biovec,
+ .decompress = zlib_decompress,
+};