[PATCH 06/10] erofs: adjust per-CPU buffers according to max_pclusterblks

[Gao Xiang]

From: Gao Xiang <hsiang...@redhat.com>

Adjust per-CPU buffers on demand since big pcluster definition is
available. Also, bail out unsupported pcluster size according to
Z_EROFS_PCLUSTER_MAX_SIZE.

Signed-off-by: Gao Xiang <hsiang...@redhat.com>
---
 fs/erofs/decompressor.c | 16 ++++++++++++----
 fs/erofs/internal.h     |  2 ++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index fb4838c0f0df..5d9f9dbd3681 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -32,6 +32,7 @@ int z_erofs_load_lz4_config(struct super_block *sb,
                            struct erofs_super_block *dsb,
                            struct z_erofs_lz4_cfgs *lz4, int size)
 {
+       struct erofs_sb_info *sbi = EROFS_SB(sb);
        u16 distance;
 
        if (lz4) {
@@ -40,16 +41,23 @@ int z_erofs_load_lz4_config(struct super_block *sb,
                        return -EINVAL;
                }
                distance = le16_to_cpu(lz4->max_distance);
+
+               sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
+               if (sbi->lz4.max_pclusterblks >
+                   Z_EROFS_PCLUSTER_MAX_SIZE / EROFS_BLKSIZ) {
+                       erofs_err(sb, "too large lz4 pcluster blocks %u",
+                                 sbi->lz4.max_pclusterblks);
+                       return -EINVAL;
+               }
        } else {
                distance = le16_to_cpu(dsb->u1.lz4_max_distance);
+               sbi->lz4.max_pclusterblks = 1;
        }
 
-       EROFS_SB(sb)->lz4.max_distance_pages = distance ?
+       sbi->lz4.max_distance_pages = distance ?
                                        DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
                                        LZ4_MAX_DISTANCE_PAGES;
-
-       /* TODO: use max pclusterblks after bigpcluster is enabled */
-       return erofs_pcpubuf_growsize(1);
+       return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
 }
 
 static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index c4b3938a7e56..f1305af50f67 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -63,6 +63,8 @@ struct erofs_fs_context {
 struct erofs_sb_lz4_info {
        /* # of pages needed for EROFS lz4 rolling decompression */
        u16 max_distance_pages;
+       /* maximum possible blocks for pclusters in the filesystem */
+       u16 max_pclusterblks;
 };
 
 struct erofs_sb_info {
-- 
2.20.1