From af2ac4c41df6d87f090613ecf3521ca073754cb0 Mon Sep 17 00:00:00 2001 From: chenguanyou Date: Wed, 24 Apr 2024 17:00:20 +0800 Subject: [PATCH 2/9] Cleanup: replace struct zspage_5_17 with union This patch is a refactoring on commit [1], and has no functional change. The reason is that the structure of zspage has not changed, just new bits have been introduced. So a union is better to reduce code replication. [1] 0172e35083b5 ("Fix "rd" command to display data on zram on Linux 5.17 and later") Signed-off-by: chenguanyou --- defs.h | 32 +++++++++++++++----------------- diskdump.c | 15 ++++++--------- 2 files changed, 21 insertions(+), 26 deletions(-) diff --git a/defs.h b/defs.h index 3cb8e63..01f316e 100644 --- a/defs.h +++ b/defs.h @@ -7407,28 +7407,26 @@ ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulon #define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) struct zspage { - struct { - unsigned int fullness : 2; - unsigned int class : 9; - unsigned int isolated : 3; - unsigned int magic : 8; + union { + unsigned int flag_bits; + struct { + unsigned int fullness : 2; + unsigned int class : 9; + unsigned int isolated : 3; + unsigned int magic : 8; + } v0; + struct { + unsigned int huge : 1; + unsigned int fullness : 2; + unsigned int class : 9; + unsigned int isolated : 3; + unsigned int magic : 8; + } v5_17; }; unsigned int inuse; unsigned int freeobj; }; -struct zspage_5_17 { - struct { - unsigned int huge : 1; - unsigned int fullness : 2; - unsigned int class : 9; - unsigned int isolated : 3; - unsigned int magic : 8; - }; - unsigned int inuse; - unsigned int freeobj; -}; - /* * makedumpfile.c */ diff --git a/diskdump.c b/diskdump.c index 4a473e1..1f7118c 100644 --- a/diskdump.c +++ b/diskdump.c @@ -2820,7 +2820,6 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) { ulong obj, off, class, page, zspage; struct zspage zspage_s; - struct zspage_5_17 zspage_5_17_s; physaddr_t paddr; unsigned int obj_idx, class_idx, size; ulong pages[2], sizes[2]; @@ -2834,15 +2833,13 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) readmem(page + OFFSET(page_private), KVADDR, &zspage, sizeof(void *), "page_private", FAULT_ON_ERROR); + readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage", FAULT_ON_ERROR); if (VALID_MEMBER(zspage_huge)) { - readmem(zspage, KVADDR, &zspage_5_17_s, - sizeof(struct zspage_5_17), "zspage_5_17", FAULT_ON_ERROR); - class_idx = zspage_5_17_s.class; - zs_magic = zspage_5_17_s.magic; + class_idx = zspage_s.v5_17.class; + zs_magic = zspage_s.v5_17.magic; } else { - readmem(zspage, KVADDR, &zspage_s, sizeof(struct zspage), "zspage", FAULT_ON_ERROR); - class_idx = zspage_s.class; - zs_magic = zspage_s.magic; + class_idx = zspage_s.v0.class; + zs_magic = zspage_s.v0.magic; } if (zs_magic != ZSPAGE_MAGIC) @@ -2888,7 +2885,7 @@ zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf) out: if (VALID_MEMBER(zspage_huge)) { - if (!zspage_5_17_s.huge) + if (!zspage_s.v5_17.huge) return (zram_buf + ZS_HANDLE_SIZE); } else { readmem(page, KVADDR, &obj, sizeof(void *), "page flags", FAULT_ON_ERROR); -- 2.40.1