The length parameter is basically duplicated for input and output in the
top level caller of the compress_pages chain. We can simply use one
variable for that and reduce stack consumption. The compression
implementation will sink the parameter to a local variable so everything
works as before.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/compression.c | 24 +++++++++++-------------
fs/btrfs/compression.h | 5 ++---
fs/btrfs/inode.c | 2 +-
fs/btrfs/lzo.c | 4 ++--
fs/btrfs/zlib.c | 3 ++-
5 files changed, 18 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 903c32c9eb22..eca4704fba9d 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -911,27 +911,25 @@ static void free_workspaces(void)
}
/*
- * given an address space and start/len, compress the bytes.
+ * Given an address space and start and length, compress the bytes into @pages
+ * that are allocated on demand.
*
- * 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.
*
- * 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
+ * @total_in is used to return the number of bytes actually read. It
+ * may be smaller than the input length 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
+ * @total_out is an in/out parameter, must be set to the input length and will
+ * be also used to return the total number of compressed bytes
*
- * max_out tells us the max number of bytes that we're allowed to
+ * @max_out tells us the max number of bytes that we're allowed to
* stuff into pages
*/
int btrfs_compress_pages(int type, struct address_space *mapping,
- u64 start, unsigned long len,
- struct page **pages,
+ u64 start, struct page **pages,
unsigned long nr_dest_pages,
unsigned long *out_pages,
unsigned long *total_in,
@@ -944,7 +942,7 @@ int btrfs_compress_pages(int type, struct address_space *mapping,
workspace = find_workspace(type);
ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
- start, len, pages,
+ start, pages,
nr_dest_pages, out_pages,
total_in, total_out,
max_out);
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 09879579fbc8..2d53879e8519 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -23,8 +23,7 @@ void btrfs_init_compress(void);
void btrfs_exit_compress(void);
int btrfs_compress_pages(int type, struct address_space *mapping,
- u64 start, unsigned long len,
- struct page **pages,
+ u64 start, struct page **pages,
unsigned long nr_dest_pages,
unsigned long *out_pages,
unsigned long *total_in,
@@ -59,7 +58,7 @@ struct btrfs_compress_op {
int (*compress_pages)(struct list_head *workspace,
struct address_space *mapping,
- u64 start, unsigned long len,
+ u64 start,
struct page **pages,
unsigned long nr_dest_pages,
unsigned long *out_pages,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dae2734a725b..7b9cdc0a1b5c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -516,7 +516,7 @@ static noinline void compress_file_range(struct inode *inode,
redirty = 1;
ret = btrfs_compress_pages(compress_type,
inode->i_mapping, start,
- total_compressed, pages,
+ pages,
nr_pages, &nr_pages_ret,
&total_in,
&total_compressed,
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 45d26980caf9..dfa690d4ce86 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -86,7 +86,7 @@ static inline size_t read_compress_length(char *buf)
static int lzo_compress_pages(struct list_head *ws,
struct address_space *mapping,
- u64 start, unsigned long len,
+ u64 start,
struct page **pages,
unsigned long nr_dest_pages,
unsigned long *out_pages,
@@ -102,7 +102,7 @@ static int lzo_compress_pages(struct list_head *ws,
struct page *in_page = NULL;
struct page *out_page = NULL;
unsigned long bytes_left;
-
+ unsigned long len = *total_out;
size_t in_len;
size_t out_len;
char *buf;
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index da497f184ff4..42d76b7824c3 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -73,7 +73,7 @@ static struct list_head *zlib_alloc_workspace(void)
static int zlib_compress_pages(struct list_head *ws,
struct address_space *mapping,
- u64 start, unsigned long len,
+ u64 start,
struct page **pages,
unsigned long nr_dest_pages,
unsigned long *out_pages,
@@ -89,6 +89,7 @@ static int zlib_compress_pages(struct list_head *ws,
struct page *in_page = NULL;
struct page *out_page = NULL;
unsigned long bytes_left;
+ unsigned long len = *total_out;
*out_pages = 0;
*total_out = 0;
--
2.10.1
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
