在 7/1/2025 10:46 PM, Jonathan Cameron 写道:
On Tue, 24 Jun 2025 07:33:51 +0000 Dongsheng Yang <dongsheng.yang@xxxxxxxxx> wrote:Introduce segment.{c,h}, an internal abstraction that encapsulates everything related to a single pcache *segment* (the fixed-size allocation unit stored on the cache-device). * On-disk metadata (`struct pcache_segment_info`) - Embedded `struct pcache_meta_header` for CRC/sequence handling. - `flags` field encodes a “has-next” bit and a 4-bit *type* class (`CACHE_DATA` added as the first type). * Initialisation - `pcache_segment_init()` populates the in-memory `struct pcache_segment` from a given segment id, data offset and metadata pointer, computing the usable `data_size` and virtual address within the DAX mapping. * IO helpers - `segment_copy_to_bio()` / `segment_copy_from_bio()` move data between pmem and a bio, using `_copy_mc_to_iter()` and `_copy_from_iter_flushcache()` to tolerate hw memory errors and ensure durability. - `segment_pos_advance()` advances an internal offset while staying inside the segment’s data area. These helpers allow upper layers (cache key management, write-back logic, GC, etc.) to treat a segment as a contiguous byte array without knowing about DAX mappings or persistence details. Signed-off-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxx>Hi Just one trivial comment.diff --git a/drivers/md/dm-pcache/segment.h b/drivers/md/dm-pcache/segment.h new file mode 100644 index 000000000000..9675951ffaf8 --- /dev/null +++ b/drivers/md/dm-pcache/segment.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _PCACHE_SEGMENT_H +#define _PCACHE_SEGMENT_H + +#include <linux/bio.h> + +#include "pcache_internal.h" + +struct pcache_segment_info { + struct pcache_meta_header header; /* Metadata header for the segment */The comment is fairly obvious given the type of the field. I'd drop the comment.
Hi Jonathan, Sounds not bad, will change it. Thanx
+ __u32 flags; + __u32 next_seg; +};
