btrfs: compression: inline alloc_workspace

Replace indirect calls to alloc_workspace by switch and calls to the
specific callbacks. This is mainly to get rid of the indirection due to
spectre vulnerability mitigations.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ffc94e1..4a8dab9 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -912,7 +912,6 @@ fail:
 
 const struct btrfs_compress_op btrfs_heuristic_compress = {
        .workspace_manager = &heuristic_wsm,
-       .alloc_workspace = alloc_heuristic_ws,
        .free_workspace = free_heuristic_ws,
 };
 
@@ -924,6 +923,22 @@ static const struct btrfs_compress_op * const btrfs_compress_op[] = {
        &btrfs_zstd_compress,
 };
 
+static struct list_head *alloc_workspace(int type, unsigned int level)
+{
+       switch (type) {
+       case BTRFS_COMPRESS_NONE: return alloc_heuristic_ws(level);
+       case BTRFS_COMPRESS_ZLIB: return zlib_alloc_workspace(level);
+       case BTRFS_COMPRESS_LZO:  return lzo_alloc_workspace(level);
+       case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(level);
+       default:
+               /*
+                * This can't happen, the type is validated several times
+                * before we get here.
+                */
+               BUG();
+       }
+}
+
 static void btrfs_init_workspace_manager(int type)
 {
        const struct btrfs_compress_op *ops = btrfs_compress_op[type];
@@ -941,7 +956,7 @@ static void btrfs_init_workspace_manager(int type)
         * Preallocate one workspace for each compression type so we can
         * guarantee forward progress in the worst case
         */
-       workspace = wsm->ops->alloc_workspace(0);
+       workspace = alloc_workspace(type, 0);
        if (IS_ERR(workspace)) {
                pr_warn(
        "BTRFS: cannot preallocate compression workspace, will try later\n");
@@ -1020,7 +1035,7 @@ again:
         * context of btrfs_compress_bio/btrfs_compress_pages
         */
        nofs_flag = memalloc_nofs_save();
-       workspace = wsm->ops->alloc_workspace(level);
+       workspace = alloc_workspace(type, level);
        memalloc_nofs_restore(nofs_flag);
 
        if (IS_ERR(workspace)) {

diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index accb1d6..8336c2e 100644 (file)
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -124,8 +124,6 @@ struct list_head *btrfs_get_workspace(int type, unsigned int level);
 void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws);
 
 struct btrfs_compress_op {
-       struct list_head *(*alloc_workspace)(unsigned int level);
-
        void (*free_workspace)(struct list_head *workspace);
 
        struct workspace_manager *workspace_manager;

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index bbf917c..39b2cf8 100644 (file)
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -484,7 +484,6 @@ out:
 
 const struct btrfs_compress_op btrfs_lzo_compress = {
        .workspace_manager      = &wsm,
-       .alloc_workspace        = lzo_alloc_workspace,
        .free_workspace         = lzo_free_workspace,
        .max_level              = 1,
        .default_level          = 1,

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index 5679a2e..c5dfab3 100644 (file)
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -400,7 +400,6 @@ next:
 
 const struct btrfs_compress_op btrfs_zlib_compress = {
        .workspace_manager      = &wsm,
-       .alloc_workspace        = zlib_alloc_workspace,
        .free_workspace         = zlib_free_workspace,
        .max_level              = 9,
        .default_level          = BTRFS_ZLIB_DEFAULT_LEVEL,

diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
index a346f11..9413f74 100644 (file)
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -708,7 +708,6 @@ finish:
 const struct btrfs_compress_op btrfs_zstd_compress = {
        /* ZSTD uses own workspace manager */
        .workspace_manager = NULL,
-       .alloc_workspace = zstd_alloc_workspace,
        .free_workspace = zstd_free_workspace,
        .max_level      = ZSTD_BTRFS_MAX_LEVEL,
        .default_level  = ZSTD_BTRFS_DEFAULT_LEVEL,