#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;
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;
- }
- spin_unlock(&workspace_lock);
- if (atomic_read(&alloc_workspace) > cpus) {
- DEFINE_WAIT(wait);
- prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
- if (atomic_read(&alloc_workspace) > cpus)
- schedule();
- finish_wait(&workspace_wait, &wait);
- goto again;
- }
- atomic_inc(&alloc_workspace);
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;
*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;
data_in = kmap(in_page);
out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -1;
+ goto out;
+ }
cpage_out = kmap(out_page);
pages[0] = out_page;
nr_pages = 1;
goto out;
}
out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_page == NULL) {
+ ret = -1;
+ goto out;
+ }
cpage_out = kmap(out_page);
pages[nr_pages] = out_page;
nr_pages++;
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)
{
- int ret = 0;
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int ret = 0, ret2;
int wbits = MAX_WBITS;
- struct workspace *workspace;
char *data_in;
size_t total_out = 0;
- unsigned long page_bytes_left;
unsigned long page_in_index = 0;
unsigned long page_out_index = 0;
- struct page *page_out;
unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
PAGE_CACHE_SIZE;
unsigned long buf_start;
- unsigned long buf_offset;
- unsigned long bytes;
- unsigned long working_bytes;
unsigned long pg_offset;
- unsigned long start_byte;
- 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.total_out = 0;
workspace->inf_strm.next_out = workspace->buf;
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
- page_out = bvec[page_out_index].bv_page;
- page_bytes_left = PAGE_CACHE_SIZE;
pg_offset = 0;
/* If it's deflate, and it's got no preset dictionary, then
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);
if (ret != Z_OK && ret != Z_STREAM_END)
break;
- /*
- * buf start is the byte offset we're of the start of
- * our workspace buffer
- */
- buf_start = total_out;
- /* total_out is the last byte of the workspace buffer */
+ buf_start = total_out;
total_out = workspace->inf_strm.total_out;
- working_bytes = total_out - buf_start;
-
- /*
- * start byte is the first byte of the page we're currently
- * copying into relative to the start of the compressed data.
- */
- start_byte = page_offset(page_out) - disk_start;
-
- if (working_bytes == 0) {
- /* we didn't make progress in this inflate
- * call, we're done
- */
- if (ret != Z_STREAM_END)
- ret = -1;
+ /* we didn't make progress in this inflate call, we're done */
+ if (buf_start == total_out)
break;
- }
- /* we haven't yet hit data corresponding to this page */
- if (total_out <= start_byte)
- goto next;
-
- /*
- * the start of the data we care about is offset into
- * the middle of our working buffer
- */
- if (total_out > start_byte && buf_start < start_byte) {
- buf_offset = start_byte - buf_start;
- working_bytes -= buf_offset;
- } else {
- buf_offset = 0;
- }
- current_buf_start = buf_start;
-
- /* copy bytes from the working buffer into the pages */
- while (working_bytes > 0) {
- bytes = min(PAGE_CACHE_SIZE - pg_offset,
- PAGE_CACHE_SIZE - buf_offset);
- bytes = min(bytes, working_bytes);
- kaddr = kmap_atomic(page_out, KM_USER0);
- memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
- bytes);
- kunmap_atomic(kaddr, KM_USER0);
- flush_dcache_page(page_out);
-
- pg_offset += bytes;
- page_bytes_left -= bytes;
- buf_offset += bytes;
- working_bytes -= bytes;
- current_buf_start += bytes;
-
- /* check if we need to pick another page */
- if (page_bytes_left == 0) {
- page_out_index++;
- if (page_out_index >= vcnt) {
- ret = 0;
- goto done;
- }
-
- page_out = bvec[page_out_index].bv_page;
- pg_offset = 0;
- page_bytes_left = PAGE_CACHE_SIZE;
- start_byte = page_offset(page_out) - disk_start;
-
- /*
- * make sure our new page is covered by this
- * working buffer
- */
- if (total_out <= start_byte)
- goto next;
-
- /* the next page in the biovec might not
- * be adjacent to the last page, but it
- * might still be found inside this working
- * buffer. bump our offset pointer
- */
- if (total_out > start_byte &&
- current_buf_start < start_byte) {
- buf_offset = start_byte - buf_start;
- working_bytes = total_out - start_byte;
- current_buf_start = buf_start +
- buf_offset;
- }
- }
+ ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
+ total_out, disk_start,
+ bvec, vcnt,
+ &page_out_index, &pg_offset);
+ if (ret2 == 0) {
+ ret = 0;
+ goto done;
}
-next:
+
workspace->inf_strm.next_out = workspace->buf;
workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
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;
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) {
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,
+};
projects / mv-sheeva.git / blobdiff