Re: [PATCH v3 6/9] dump: Introduce dump_is_64bit() helper function

[Marc-André Lureau]

On Wed, Mar 30, 2022 at 4:44 PM Janosch Frank <frankja@linux.ibm.com> wrote:

Checking d_class in dump_info leads to lengthy conditionals so let's
shorten things a bit by introducing a helper function.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

 

---
 dump/dump.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/dump/dump.c b/dump/dump.c
index 4be4dcab24..a7cf112d8f 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -55,6 +55,11 @@ static Error *dump_migration_blocker;
       DIV_ROUND_UP((name_size), 4) +                    \
       DIV_ROUND_UP((desc_size), 4)) * 4)

+static inline bool dump_is_64bit(DumpState *s)
+{
+    return s->dump_info.d_class == ELFCLASS64;
+}
+
 uint16_t cpu_to_dump16(DumpState *s, uint16_t val)
 {
     if (s->dump_info.d_endian == ELFDATA2LSB) {
@@ -479,7 +484,7 @@ static void write_elf_loads(DumpState *s, Error **errp)
         get_offset_range(memory_mapping->phys_addr,
                          memory_mapping->length,
                          s, &offset, &filesz);
-        if (s->dump_info.d_class == ELFCLASS64) {
+        if (dump_is_64bit(s)) {
             write_elf64_load(s, memory_mapping, phdr_index++, offset,
                              filesz, errp);
         } else {
@@ -527,7 +532,7 @@ static void dump_begin(DumpState *s, Error **errp)
      */

     /* write elf header to vmcore */
-    if (s->dump_info.d_class == ELFCLASS64) {
+    if (dump_is_64bit(s)) {
         write_elf64_header(s, errp);
     } else {
         write_elf32_header(s, errp);
@@ -536,7 +541,7 @@ static void dump_begin(DumpState *s, Error **errp)
         return;
     }

-    if (s->dump_info.d_class == ELFCLASS64) {
+    if (dump_is_64bit(s)) {
         /* write PT_NOTE to vmcore */
         write_elf64_note(s, errp);
         if (*errp) {
@@ -747,7 +752,7 @@ static void get_note_sizes(DumpState *s, const void *note,
     uint64_t name_sz;
     uint64_t desc_sz;

-    if (s->dump_info.d_class == ELFCLASS64) {
+    if (dump_is_64bit(s)) {
         const Elf64_Nhdr *hdr = note;
         note_head_sz = sizeof(Elf64_Nhdr);
         name_sz = tswap64(hdr->n_namesz);
@@ -1007,10 +1012,10 @@ out:

 static void write_dump_header(DumpState *s, Error **errp)
 {
-    if (s->dump_info.d_class == ELFCLASS32) {
-        create_header32(s, errp);
-    } else {
+    if (dump_is_64bit(s)) {
         create_header64(s, errp);
+    } else {
+        create_header32(s, errp);
     }
 }

@@ -1697,8 +1702,8 @@ static void dump_init(DumpState *s, int fd, bool has_format,
         uint32_t size;
         uint16_t format;

-        note_head_size = s->dump_info.d_class == ELFCLASS32 ?
-            sizeof(Elf32_Nhdr) : sizeof(Elf64_Nhdr);
+        note_head_size = dump_is_64bit(s) ?
+            sizeof(Elf64_Nhdr) : sizeof(Elf32_Nhdr);

         format = le16_to_cpu(vmci->vmcoreinfo.guest_format);
         size = le32_to_cpu(vmci->vmcoreinfo.size);
@@ -1801,7 +1806,7 @@ static void dump_init(DumpState *s, int fd, bool has_format,
         }
     }

-    if (s->dump_info.d_class == ELFCLASS64) {
+    if (dump_is_64bit(s)) {
         s->phdr_offset = sizeof(Elf64_Ehdr);
         s->shdr_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
         s->note_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
--
2.32.0

--

Marc-André Lureau