[Crash-utility] [PATCH 1/5] diskdump, zram: cleanup try_zram_decompress()

This clean up makes later commits a bit readable. Signed-off-by: HATAYAMA Daisuke <d.hatayama(a)fujitsu.com&gt; --- diskdump.c | 145 ++++++++++++++++++++++++++++++++----------------------------- 1 file changed, 75 insertions(+), 70 deletions(-) diff --git a/diskdump.c b/diskdump.c index 63a08a1..dcc7142 100644 --- a/diskdump.c +++ b/diskdump.c @@ -2743,85 +2743,90 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong sizeof(void *), "block_device_bd_disk", FAULT_ON_ERROR); readmem(bd_disk + OFFSET(gendisk_disk_name), KVADDR, name, strlen("zram"), "gendisk_disk_name", FAULT_ON_ERROR); - if (!strncmp(name, "zram", strlen("zram"))) { + + if (strncmp(name, "zram", strlen("zram"))) { if (CRASHDEBUG(2)) - error(WARNING, "this page has swapped to zram\n"); - - readmem(bd_disk + OFFSET(gendisk_private_data), KVADDR, &zram, - sizeof(void *), "gendisk_private_data", FAULT_ON_ERROR); - - readmem(zram + OFFSET(zram_compressor), KVADDR, name, - sizeof(name), "zram compressor", FAULT_ON_ERROR); - if (STREQ(name, "lzo")) { - if (!(dd->flags & LZO_SUPPORTED)) { - if (lzo_init() == LZO_E_OK) - dd->flags |= LZO_SUPPORTED; - else - return 0; - } - decompressor = (void *)lzo1x_decompress_safe; - } else {//todo,support more compressor - error(WARNING, "only the lzo compressor is supported\n"); - return 0; - } + error(WARNING, + "this page has been swapped to %s\n", + name); + return 0; + } - if (THIS_KERNEL_VERSION >= LINUX(2, 6, 0)) { - swp_offset = (ulonglong)__swp_offset(pte_val); - } else { - swp_offset = (ulonglong)SWP_OFFSET(pte_val); - } + if (CRASHDEBUG(2)) + error(WARNING, "this page has swapped to zram\n"); - zram_buf = (unsigned char *)GETBUF(PAGESIZE()); - /*lookup page from swap cache*/ - obj_addr = lookup_swap_cache(pte_val, zram_buf); - if (obj_addr != NULL) { - memcpy(buf, obj_addr + off, len); - goto out; - } + readmem(bd_disk + OFFSET(gendisk_private_data), KVADDR, &zram, + sizeof(void *), "gendisk_private_data", FAULT_ON_ERROR); - sector = swp_offset << (PAGESHIFT() - 9); - index = sector >> SECTORS_PER_PAGE_SHIFT; - readmem(zram, KVADDR, &zram_table_entry, - sizeof(void *), "zram_table_entry", FAULT_ON_ERROR); - zram_table_entry += (index * SIZE(zram_table_entry)); - readmem(zram_table_entry, KVADDR, &entry, - sizeof(void *), "entry of table", FAULT_ON_ERROR); - readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags, - sizeof(void *), "zram_table_flag", FAULT_ON_ERROR); - if (!entry || (flags & ZRAM_FLAG_SAME_BIT)) { - memset(buf, entry, len); - goto out; - } - size = flags & (ZRAM_FLAG_SHIFT -1); - if (size == 0) { - len = 0; - goto out; + readmem(zram + OFFSET(zram_compressor), KVADDR, name, + sizeof(name), "zram compressor", FAULT_ON_ERROR); + if (STREQ(name, "lzo")) { + if (!(dd->flags & LZO_SUPPORTED)) { + if (lzo_init() == LZO_E_OK) + dd->flags |= LZO_SUPPORTED; + else + return 0; } + decompressor = (void *)lzo1x_decompress_safe; + } else {//todo,support more compressor + error(WARNING, "only the lzo compressor is supported\n"); + return 0; + } - readmem(zram + OFFSET(zram_mempoll), KVADDR, &zram, - sizeof(void *), "zram_mempoll", FAULT_ON_ERROR); + if (THIS_KERNEL_VERSION >= LINUX(2, 6, 0)) { + swp_offset = (ulonglong)__swp_offset(pte_val); + } else { + swp_offset = (ulonglong)SWP_OFFSET(pte_val); + } - obj_addr = zram_object_addr(zram, entry, zram_buf); - if (obj_addr == NULL) { - len = 0; - goto out; - } + zram_buf = (unsigned char *)GETBUF(PAGESIZE()); + /*lookup page from swap cache*/ + obj_addr = lookup_swap_cache(pte_val, zram_buf); + if (obj_addr != NULL) { + memcpy(buf, obj_addr + off, len); + goto out; + } - if (size == PAGESIZE()) { - memcpy(buf, obj_addr + off, len); - } else { - outbuf = (unsigned char *)GETBUF(PAGESIZE()); - outsize = PAGESIZE(); - if (!decompressor(obj_addr, size, outbuf, &outsize, NULL)) - memcpy(buf, outbuf + off, len); - else { - error(WARNING, "zram decompress error\n"); - len = 0; - } - FREEBUF(outbuf); - } + sector = swp_offset << (PAGESHIFT() - 9); + index = sector >> SECTORS_PER_PAGE_SHIFT; + readmem(zram, KVADDR, &zram_table_entry, + sizeof(void *), "zram_table_entry", FAULT_ON_ERROR); + zram_table_entry += (index * SIZE(zram_table_entry)); + readmem(zram_table_entry, KVADDR, &entry, + sizeof(void *), "entry of table", FAULT_ON_ERROR); + readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags, + sizeof(void *), "zram_table_flag", FAULT_ON_ERROR); + if (!entry || (flags & ZRAM_FLAG_SAME_BIT)) { + memset(buf, entry, len); + goto out; + } + size = flags & (ZRAM_FLAG_SHIFT -1); + if (size == 0) { + len = 0; + goto out; + } + + readmem(zram + OFFSET(zram_mempoll), KVADDR, &zram, + sizeof(void *), "zram_mempoll", FAULT_ON_ERROR); + + obj_addr = zram_object_addr(zram, entry, zram_buf); + if (obj_addr == NULL) { + len = 0; + goto out; + } + + if (size == PAGESIZE()) { + memcpy(buf, obj_addr + off, len); } else { - return 0; + outbuf = (unsigned char *)GETBUF(PAGESIZE()); + outsize = PAGESIZE(); + if (!decompressor(obj_addr, size, outbuf, &outsize, NULL)) + memcpy(buf, outbuf + off, len); + else { + error(WARNING, "zram decompress error\n"); + len = 0; + } + FREEBUF(outbuf); } out: -- 1.8.3.1