[Qemu-devel] [PATCH] vpc: fix beX_to_cpu() and cpu_to_beX() confusion

* [Qemu-devel] [PATCH] vpc: fix beX_to_cpu() and cpu_to_beX() confusion
@ 2014-09-23  9:40 Stefan Hajnoczi
  2014-09-24 15:17 ` Xiaodong Gong
  2014-09-25  7:43 ` Kevin Wolf
  0 siblings, 2 replies; 3+ messages in thread
From: Stefan Hajnoczi @ 2014-09-23  9:40 UTC (permalink / raw)
  To: qemu-devel; +Cc: Kevin Wolf, Jeff Cody, pl, Stefan Hajnoczi, Xiaodong Gong

The beX_to_cpu() and cpu_to_beX() functions perform the same operation -
they do a byteswap if the host CPU endianness is little-endian or a
nothing otherwise.

The point of two names for the same operation is that it documents which
direction the data is being converted.  This makes it clear whether the
data is suitable for CPU processing or in its external representation.

This patch fixes incorrect beX_to_cpu()/cpu_to_beX() usage.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/vpc.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/block/vpc.c b/block/vpc.c
index 4947369..e08144a 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -207,7 +207,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
             "incorrect.\n", bs->filename);
 
     /* Write 'checksum' back to footer, or else will leave it with zero. */
-    footer->checksum = be32_to_cpu(checksum);
+    footer->checksum = cpu_to_be32(checksum);
 
     // The visible size of a image in Virtual PC depends on the geometry
     // rather than on the size stored in the footer (the size in the footer
@@ -472,7 +472,7 @@ static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
 
     // Write BAT entry to disk
     bat_offset = s->bat_offset + (4 * index);
-    bat_value = be32_to_cpu(s->pagetable[index]);
+    bat_value = cpu_to_be32(s->pagetable[index]);
     ret = bdrv_pwrite_sync(bs->file, bat_offset, &bat_value, 4);
     if (ret < 0)
         goto fail;
@@ -699,13 +699,13 @@ static int create_dynamic_disk(BlockDriverState *bs, uint8_t *buf,
      * Note: The spec is actually wrong here for data_offset, it says
      * 0xFFFFFFFF, but MS tools expect all 64 bits to be set.
      */
-    dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFFULL);
-    dyndisk_header->table_offset = be64_to_cpu(3 * 512);
-    dyndisk_header->version = be32_to_cpu(0x00010000);
-    dyndisk_header->block_size = be32_to_cpu(block_size);
-    dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
+    dyndisk_header->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
+    dyndisk_header->table_offset = cpu_to_be64(3 * 512);
+    dyndisk_header->version = cpu_to_be32(0x00010000);
+    dyndisk_header->block_size = cpu_to_be32(block_size);
+    dyndisk_header->max_table_entries = cpu_to_be32(num_bat_entries);
 
-    dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
+    dyndisk_header->checksum = cpu_to_be32(vpc_checksum(buf, 1024));
 
     // Write the header
     offset = 512;
@@ -810,36 +810,36 @@ static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
     memcpy(footer->creator_app, "qemu", 4);
     memcpy(footer->creator_os, "Wi2k", 4);
 
-    footer->features = be32_to_cpu(0x02);
-    footer->version = be32_to_cpu(0x00010000);
+    footer->features = cpu_to_be32(0x02);
+    footer->version = cpu_to_be32(0x00010000);
     if (disk_type == VHD_DYNAMIC) {
-        footer->data_offset = be64_to_cpu(HEADER_SIZE);
+        footer->data_offset = cpu_to_be64(HEADER_SIZE);
     } else {
-        footer->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFFULL);
+        footer->data_offset = cpu_to_be64(0xFFFFFFFFFFFFFFFFULL);
     }
-    footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
+    footer->timestamp = cpu_to_be32(time(NULL) - VHD_TIMESTAMP_BASE);
 
     /* Version of Virtual PC 2007 */
-    footer->major = be16_to_cpu(0x0005);
-    footer->minor = be16_to_cpu(0x0003);
+    footer->major = cpu_to_be16(0x0005);
+    footer->minor = cpu_to_be16(0x0003);
     if (disk_type == VHD_DYNAMIC) {
-        footer->orig_size = be64_to_cpu(total_sectors * 512);
-        footer->size = be64_to_cpu(total_sectors * 512);
+        footer->orig_size = cpu_to_be64(total_sectors * 512);
+        footer->size = cpu_to_be64(total_sectors * 512);
     } else {
-        footer->orig_size = be64_to_cpu(total_size);
-        footer->size = be64_to_cpu(total_size);
+        footer->orig_size = cpu_to_be64(total_size);
+        footer->size = cpu_to_be64(total_size);
     }
-    footer->cyls = be16_to_cpu(cyls);
+    footer->cyls = cpu_to_be16(cyls);
     footer->heads = heads;
     footer->secs_per_cyl = secs_per_cyl;
 
-    footer->type = be32_to_cpu(disk_type);
+    footer->type = cpu_to_be32(disk_type);
 
 #if defined(CONFIG_UUID)
     uuid_generate(footer->uuid);
 #endif
 
-    footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
+    footer->checksum = cpu_to_be32(vpc_checksum(buf, HEADER_SIZE));
 
     if (disk_type == VHD_DYNAMIC) {
         ret = create_dynamic_disk(bs, buf, total_sectors);
-- 
1.9.3

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