|
| From: | zhanghailiang |
| Subject: | Re: [Qemu-devel] [PATCH v6 2/2] dump: Don't return error code when return an Error object |
| Date: | Tue, 30 Sep 2014 16:39:47 +0800 |
| User-agent: | Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 |
On 2014/9/29 16:06, Markus Armbruster wrote:
zhanghailiang <address@hidden> writes:Functions shouldn't return an error code and an Error object at the same time. Turn all these functions that returning Error object to void. We also judge if a function success or fail by reference to the local_err. Signed-off-by: zhanghailiang <address@hidden> --- dump.c | 313 +++++++++++++++++++++++++++++++---------------------------------- 1 file changed, 148 insertions(+), 165 deletions(-) diff --git a/dump.c b/dump.c index 07d2300..a6188b3 100644 --- a/dump.c +++ b/dump.c @@ -100,7 +100,7 @@ static int fd_write_vmcore(const void *buf, size_t size, void *opaque) return 0; } -static int write_elf64_header(DumpState *s, Error **errp) +static void write_elf64_header(DumpState *s, Error **errp) { Elf64_Ehdr elf_header; int ret; @@ -128,13 +128,10 @@ static int write_elf64_header(DumpState *s, Error **errp) ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s); if (ret < 0) { dump_error(s, "dump: failed to write elf header", errp); - return -1; } - - return 0; } -static int write_elf32_header(DumpState *s, Error **errp) +static void write_elf32_header(DumpState *s, Error **errp) { Elf32_Ehdr elf_header; int ret; @@ -162,13 +159,10 @@ static int write_elf32_header(DumpState *s, Error **errp) ret = fd_write_vmcore(&elf_header, sizeof(elf_header), s); if (ret < 0) { dump_error(s, "dump: failed to write elf header", errp); - return -1; } - - return 0; } -static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, +static void write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, int phdr_index, hwaddr offset, hwaddr filesz, Error **errp) { @@ -188,15 +182,12 @@ static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table", errp); - return -1; } - - return 0; } -static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping, - int phdr_index, hwaddr offset, - hwaddr filesz, Error **errp) +static void write_elf32_load(DumpState *s, MemoryMapping *memory_mapping, + int phdr_index, hwaddr offset, + hwaddr filesz, Error **errp) { Elf32_Phdr phdr; int ret; @@ -214,13 +205,10 @@ static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping, ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table", errp); - return -1; } - - return 0; } -static int write_elf64_note(DumpState *s, Error **errp) +static void write_elf64_note(DumpState *s, Error **errp) { Elf64_Phdr phdr; hwaddr begin = s->memory_offset - s->note_size; @@ -237,10 +225,7 @@ static int write_elf64_note(DumpState *s, Error **errp) ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table", errp); - return -1; } - - return 0; } static inline int cpu_index(CPUState *cpu) @@ -248,8 +233,8 @@ static inline int cpu_index(CPUState *cpu) return cpu->cpu_index + 1; } -static int write_elf64_notes(WriteCoreDumpFunction f, DumpState *s, - Error **errp) +static void write_elf64_notes(WriteCoreDumpFunction f, DumpState *s, + Error **errp) { CPUState *cpu; int ret; @@ -260,7 +245,7 @@ static int write_elf64_notes(WriteCoreDumpFunction f, DumpState *s, ret = cpu_write_elf64_note(f, cpu, id, s); if (ret < 0) { dump_error(s, "dump: failed to write elf notes", errp); - return -1; + return; } } @@ -268,14 +253,12 @@ static int write_elf64_notes(WriteCoreDumpFunction f, DumpState *s, ret = cpu_write_elf64_qemunote(f, cpu, s); if (ret < 0) { dump_error(s, "dump: failed to write CPU status", errp); - return -1; + return; } } - - return 0; } -static int write_elf32_note(DumpState *s, Error **errp) +static void write_elf32_note(DumpState *s, Error **errp) { hwaddr begin = s->memory_offset - s->note_size; Elf32_Phdr phdr; @@ -292,14 +275,11 @@ static int write_elf32_note(DumpState *s, Error **errp) ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table", errp); - return -1; } - - return 0; } -static int write_elf32_notes(WriteCoreDumpFunction f, DumpState *s, - Error **errp) +static void write_elf32_notes(WriteCoreDumpFunction f, DumpState *s, + Error **errp) { CPUState *cpu; int ret; @@ -310,7 +290,7 @@ static int write_elf32_notes(WriteCoreDumpFunction f, DumpState *s, ret = cpu_write_elf32_note(f, cpu, id, s); if (ret < 0) { dump_error(s, "dump: failed to write elf notes", errp); - return -1; + return; } } @@ -318,14 +298,12 @@ static int write_elf32_notes(WriteCoreDumpFunction f, DumpState *s, ret = cpu_write_elf32_qemunote(f, cpu, s); if (ret < 0) { dump_error(s, "dump: failed to write CPU status", errp); - return -1; + return; } } - - return 0; } -static int write_elf_section(DumpState *s, int type, Error **errp) +static void write_elf_section(DumpState *s, int type, Error **errp) { Elf32_Shdr shdr32; Elf64_Shdr shdr64; @@ -348,49 +326,45 @@ static int write_elf_section(DumpState *s, int type, Error **errp) ret = fd_write_vmcore(&shdr, shdr_size, s); if (ret < 0) { dump_error(s, "dump: failed to write section header table", errp); - return -1; + return; } - - return 0; } -static int write_data(DumpState *s, void *buf, int length, Error **errp) +static void write_data(DumpState *s, void *buf, int length, Error **errp) { int ret; ret = fd_write_vmcore(buf, length, s); if (ret < 0) { dump_error(s, "dump: failed to save memory", errp); - return -1; + return; } - - return 0; } /* write the memroy to vmcore. 1 page per I/O. */ -static int write_memory(DumpState *s, GuestPhysBlock *block, ram_addr_t start, - int64_t size, Error **errp) +static void write_memory(DumpState *s, GuestPhysBlock *block, ram_addr_t start, + int64_t size, Error **errp) { int64_t i; - int ret; + Error *local_err = NULL; for (i = 0; i < size / TARGET_PAGE_SIZE; i++) { - ret = write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE, - TARGET_PAGE_SIZE, errp); - if (ret < 0) { - return ret; + write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE, + TARGET_PAGE_SIZE, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } } if ((size % TARGET_PAGE_SIZE) != 0) { - ret = write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE, - size % TARGET_PAGE_SIZE, errp); - if (ret < 0) { - return ret; + write_data(s, block->host_addr + start + i * TARGET_PAGE_SIZE, + size % TARGET_PAGE_SIZE, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } } - - return 0; } /* get the memory's offset and size in the vmcore */ @@ -455,13 +429,13 @@ static void get_offset_range(hwaddr phys_addr, } } -static int write_elf_loads(DumpState *s, Error **errp) +static void write_elf_loads(DumpState *s, Error **errp) { hwaddr offset, filesz; MemoryMapping *memory_mapping; uint32_t phdr_index = 1; - int ret; uint32_t max_index; + Error *local_err = NULL; if (s->have_section) { max_index = s->sh_info; @@ -474,29 +448,28 @@ static int write_elf_loads(DumpState *s, Error **errp) memory_mapping->length, s, &offset, &filesz); if (s->dump_info.d_class == ELFCLASS64) { - ret = write_elf64_load(s, memory_mapping, phdr_index++, offset, - filesz, errp); + write_elf64_load(s, memory_mapping, phdr_index++, offset, + filesz, &local_err); } else { - ret = write_elf32_load(s, memory_mapping, phdr_index++, offset, - filesz, errp); + write_elf32_load(s, memory_mapping, phdr_index++, offset, + filesz, &local_err); } - if (ret < 0) { - return -1; + if (local_err) { + error_propagate(errp, local_err); + return; } if (phdr_index >= max_index) { break; } } - - return 0; } /* write elf header, PT_NOTE and elf note to vmcore. */ -static int dump_begin(DumpState *s, Error **errp) +static void dump_begin(DumpState *s, Error **errp) { - int ret; + Error *local_err = NULL; /* * the vmcore's format is: @@ -524,62 +497,76 @@ static int dump_begin(DumpState *s, Error **errp) /* write elf header to vmcore */ if (s->dump_info.d_class == ELFCLASS64) { - ret = write_elf64_header(s, errp); + write_elf64_header(s, &local_err); } else { - ret = write_elf32_header(s, errp); + write_elf32_header(s, &local_err); } - if (ret < 0) { - return -1; + if (local_err) { + error_propagate(errp, local_err); + return; } if (s->dump_info.d_class == ELFCLASS64) { /* write PT_NOTE to vmcore */ - if (write_elf64_note(s, errp) < 0) { - return -1; + write_elf64_note(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } /* write all PT_LOAD to vmcore */ - if (write_elf_loads(s, errp) < 0) { - return -1; + write_elf_loads(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } /* write section to vmcore */ if (s->have_section) { - if (write_elf_section(s, 1, errp) < 0) { - return -1; + write_elf_section(s, 1, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } } /* write notes to vmcore */ - if (write_elf64_notes(fd_write_vmcore, s, errp) < 0) { - return -1; + write_elf64_notes(fd_write_vmcore, s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } - } else { /* write PT_NOTE to vmcore */ - if (write_elf32_note(s, errp) < 0) { - return -1; + write_elf32_note(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } /* write all PT_LOAD to vmcore */ - if (write_elf_loads(s, errp) < 0) { - return -1; + write_elf_loads(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } /* write section to vmcore */ if (s->have_section) { - if (write_elf_section(s, 0, errp) < 0) { - return -1; + write_elf_section(s, 0, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } } /* write notes to vmcore */ - if (write_elf32_notes(fd_write_vmcore, s, errp) < 0) { - return -1; + write_elf32_notes(fd_write_vmcore, s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } } - - return 0; } /* write PT_LOAD to vmcore */static int dump_completed(DumpState *s) { dump_cleanup(s); return 0; } I doubt this comment is accurate. Outside the scope of this patch.
Er, i will clean it and also change this function to void in this patch. Thanks.
@@ -617,11 +604,12 @@ static int get_next_block(DumpState *s, GuestPhysBlock *block) } /* write all memory to vmcore */ -static int dump_iterate(DumpState *s, Error **errp) +static void dump_iterate(DumpState *s, Error **errp) { GuestPhysBlock *block; int64_t size; int ret; + Error *local_err = NULL; while (1) { block = s->next_block; @@ -633,34 +621,35 @@ static int dump_iterate(DumpState *s, Error **errp) size -= block->target_end - (s->begin + s->length); } } - ret = write_memory(s, block, s->start, size, errp); - if (ret == -1) { - return ret; + write_memory(s, block, s->start, size, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } ret = get_next_block(s, block); if (ret == 1) { dump_completed(s); - return 0; } } } -static int create_vmcore(DumpState *s, Error **errp) +static void create_vmcore(DumpState *s, Error **errp) { - int ret; + Error *local_err = NULL; - ret = dump_begin(s, errp); - if (ret < 0) { - return -1; + dump_begin(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } - ret = dump_iterate(s, errp); - if (ret < 0) { - return -1; + dump_iterate(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; }Please drop this blank line, like you do elsewhere.
OK!
- return 0; }You need local_err when you want to examine the error. You do after dump_begin(), because you want to return early on error. You don't after dump_iterate(). There, you could simply call dump_iterate(s, errp); and be done with it. Your choice.
You are right, it is unnecessary. Will remove this check. Thanks;)
static int write_start_flat_header(int fd) @@ -741,9 +730,8 @@ static int buf_write_note(const void *buf, size_t size, void *opaque) } /* write common header, sub header and elf note to vmcore */ -static int create_header32(DumpState *s, Error **errp) +static void create_header32(DumpState *s, Error **errp) { - int ret = 0; DiskDumpHeader32 *dh = NULL; KdumpSubHeader32 *kh = NULL; size_t size; @@ -752,6 +740,7 @@ static int create_header32(DumpState *s, Error **errp) uint32_t bitmap_blocks; uint32_t status = 0; uint64_t offset_note; + Error *local_err = NULL; /* write common header, the version of kdump-compressed format is 6th */ size = sizeof(DiskDumpHeader32); @@ -788,7 +777,6 @@ static int create_header32(DumpState *s, Error **errp) if (write_buffer(s->fd, 0, dh, size) < 0) { dump_error(s, "dump: failed to write disk dump header", errp); - ret = -1; goto out; } @@ -808,7 +796,6 @@ static int create_header32(DumpState *s, Error **errp) if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS * block_size, kh, size) < 0) { dump_error(s, "dump: failed to write kdump sub header", errp); - ret = -1; goto out; } @@ -817,15 +804,14 @@ static int create_header32(DumpState *s, Error **errp) s->note_buf_offset = 0; /* use s->note_buf to store notes temporarily */ - if (write_elf32_notes(buf_write_note, s, errp) < 0) { - ret = -1; + write_elf32_notes(buf_write_note, s, &local_err); + if (local_err) { + error_propagate(errp, local_err); goto out; } - if (write_buffer(s->fd, offset_note, s->note_buf, s->note_size) < 0) { dump_error(s, "dump: failed to write notes", errp); - ret = -1; goto out; } @@ -841,14 +827,11 @@ out: g_free(dh); g_free(kh); g_free(s->note_buf); - - return ret; } /* write common header, sub header and elf note to vmcore */ -static int create_header64(DumpState *s, Error **errp) +static void create_header64(DumpState *s, Error **errp) { - int ret = 0; DiskDumpHeader64 *dh = NULL; KdumpSubHeader64 *kh = NULL; size_t size; @@ -857,6 +840,7 @@ static int create_header64(DumpState *s, Error **errp) uint32_t bitmap_blocks; uint32_t status = 0; uint64_t offset_note; + Error *local_err = NULL; /* write common header, the version of kdump-compressed format is 6th */ size = sizeof(DiskDumpHeader64); @@ -893,7 +877,6 @@ static int create_header64(DumpState *s, Error **errp) if (write_buffer(s->fd, 0, dh, size) < 0) { dump_error(s, "dump: failed to write disk dump header", errp); - ret = -1; goto out; } @@ -913,7 +896,6 @@ static int create_header64(DumpState *s, Error **errp) if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS * block_size, kh, size) < 0) { dump_error(s, "dump: failed to write kdump sub header", errp); - ret = -1; goto out; } @@ -922,15 +904,15 @@ static int create_header64(DumpState *s, Error **errp) s->note_buf_offset = 0; /* use s->note_buf to store notes temporarily */ - if (write_elf64_notes(buf_write_note, s, errp) < 0) { - ret = -1; + write_elf64_notes(buf_write_note, s, &local_err); + if (local_err) { + error_propagate(errp, local_err); goto out; } if (write_buffer(s->fd, offset_note, s->note_buf, s->note_size) < 0) { dump_error(s, "dump: failed to write notes", errp); - ret = -1; goto out; } @@ -946,16 +928,19 @@ out: g_free(dh); g_free(kh); g_free(s->note_buf); - - return ret; } -static int write_dump_header(DumpState *s, Error **errp) +static void write_dump_header(DumpState *s, Error **errp) { + Error *local_err = NULL; + if (s->dump_info.d_class == ELFCLASS32) { - return create_header32(s, errp); + create_header32(s, &local_err); } else { - return create_header64(s, errp); + create_header64(s, &local_err); + } + if (local_err) { + error_propagate(errp, local_err); } } @@ -1069,7 +1054,7 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr, return true; } -static int write_dump_bitmap(DumpState *s, Error **errp) +static void write_dump_bitmap(DumpState *s, Error **errp) { int ret = 0; uint64_t last_pfn, pfn; @@ -1091,7 +1076,6 @@ static int write_dump_bitmap(DumpState *s, Error **errp) ret = set_dump_bitmap(last_pfn, pfn, true, dump_bitmap_buf, s); if (ret < 0) { dump_error(s, "dump: failed to set dump_bitmap", errp); - ret = -1; goto out; } @@ -1109,7 +1093,6 @@ static int write_dump_bitmap(DumpState *s, Error **errp) dump_bitmap_buf, s); if (ret < 0) { dump_error(s, "dump: failed to sync dump_bitmap", errp); - ret = -1; goto out; } } @@ -1119,8 +1102,6 @@ static int write_dump_bitmap(DumpState *s, Error **errp) out: g_free(dump_bitmap_buf); - - return ret; } static void prepare_data_cache(DataCache *data_cache, DumpState *s, @@ -1200,7 +1181,7 @@ static inline bool is_zero_page(const uint8_t *buf, size_t page_size) return buffer_is_zero(buf, page_size); } -static int write_dump_pages(DumpState *s, Error **errp) +static void write_dump_pages(DumpState *s, Error **errp) { int ret = 0; DataCache page_desc, page_data; @@ -1365,13 +1346,12 @@ out: #endif g_free(buf_out); - - return ret; } -static int create_kdump_vmcore(DumpState *s, Error **errp) +static void create_kdump_vmcore(DumpState *s, Error **errp) { int ret; + Error *local_err = NULL; /* * the kdump-compressed format is: @@ -1398,33 +1378,34 @@ static int create_kdump_vmcore(DumpState *s, Error **errp) ret = write_start_flat_header(s->fd); if (ret < 0) { dump_error(s, "dump: failed to write start flat header", errp); - return -1; + return; } - ret = write_dump_header(s, errp); - if (ret < 0) { - return -1; + write_dump_header(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } - ret = write_dump_bitmap(s, errp); - if (ret < 0) { - return -1; + write_dump_bitmap(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } - ret = write_dump_pages(s, errp); - if (ret < 0) { - return -1; + write_dump_pages(s, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; } ret = write_end_flat_header(s->fd); if (ret < 0) { dump_error(s, "dump: failed to write end flat header", errp); - return -1; + return; } dump_completed(s); - - return 0; } static ram_addr_t get_start_block(DumpState *s) @@ -1463,9 +1444,9 @@ static void get_max_mapnr(DumpState *s) s->max_mapnr = paddr_to_pfn(last_block->target_end); } -static int dump_init(DumpState *s, int fd, bool has_format, - DumpGuestMemoryFormat format, bool paging, bool has_filter, - int64_t begin, int64_t length, Error **errp) +static void dump_init(DumpState *s, int fd, bool has_format, + DumpGuestMemoryFormat format, bool paging, bool has_filter, + int64_t begin, int64_t length, Error **errp) { CPUState *cpu; int nr_cpus; @@ -1570,7 +1551,7 @@ static int dump_init(DumpState *s, int fd, bool has_format, s->flag_compress = 0; } - return 0; + return; } if (s->has_filter) { @@ -1619,11 +1600,10 @@ static int dump_init(DumpState *s, int fd, bool has_format, } } - return 0; + return; cleanup: dump_cleanup(s); - return -1; } void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin, @@ -1634,7 +1614,7 @@ void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin, const char *p; int fd = -1; DumpState *s; - int ret; + Error *local_err = NULL; /* * kdump-compressed format need the whole memory dumped, so paging or @@ -1694,19 +1674,22 @@ void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin, s = g_malloc0(sizeof(DumpState)); - ret = dump_init(s, fd, has_format, format, paging, has_begin, - begin, length, errp); - if (ret < 0) { + dump_init(s, fd, has_format, format, paging, has_begin, + begin, length, &local_err); + if (local_err) { g_free(s); + error_propagate(errp, local_err); return; } if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) { - create_kdump_vmcore(s, errp); + create_kdump_vmcore(s, &local_err); } else { - create_vmcore(s, errp); + create_vmcore(s, &local_err); + } + if (local_err) { + error_propagate(errp, local_err); } - g_free(s); }Another case where local_err isn't needed. You could simplify to just if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) { create_kdump_vmcore(s, errp); } else { create_vmcore(s, errp); } g_free(s);
OK, Will fix it. Thanks.
This patch illustrates why I dislike void functions with an Error ** parameter: lots of busy-work with error_propagate(). But others feel it's what we should do. *shrug*
;)
Patch looks correct to me on a glance. I'm leaving real review to the folks who think it's what we should do. .
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