[Xen-changelog] [xen-3.4-testing] blktap: fix and use ROUNDUP macro (bug 1430 part 1)

["Xen patchbot-3.4-testing" <patchbot-3.4-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1244038567 -3600
# Node ID 69293fc2096f83943bc607a9456fcc383746e7a9
# Parent  29d7e3522cc5e0efb898cf4eb0f95e75e53b7a2d
blktap: fix and use ROUNDUP macro (bug 1430 part 1)

As pointed out in Xen Bugzilla 1430 in the blktap QCOW driver the
rounding function is wrong in line 824 of block-qcow.c.
This patch replaces this (and other roundings) with the already
existing ROUNDUP macro (and fixes the usual macro pitfall).

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
xen-unstable changeset:   19701:f989778298d8
xen-unstable date:        Wed Jun 03 11:11:04 2009 +0100
---
 tools/blktap/drivers/block-qcow.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff -r 29d7e3522cc5 -r 69293fc2096f tools/blktap/drivers/block-qcow.c
--- a/tools/blktap/drivers/block-qcow.c Mon Jun 01 14:56:17 2009 +0100
+++ b/tools/blktap/drivers/block-qcow.c Wed Jun 03 15:16:07 2009 +0100
@@ -55,7 +55,7 @@
 #define ROUNDUP(l, s) \
 ({ \
     (uint64_t)( \
-        (l + (s - 1)) - ((l + (s - 1)) % s)); \
+        ((l) + ((s) - 1)) - (((l) + ((s) - 1)) % (s))); \
 })
 
 #undef IOCB_IDX
@@ -800,14 +800,14 @@ static int tdqcow_open (struct disk_driv
 
        /* read the level 1 table */
        shift = s->cluster_bits + s->l2_bits;
-       s->l1_size = (header->size + (1LL << shift) - 1) >> shift;
+       s->l1_size = ROUNDUP(header->size, 1LL << shift);
        
        s->l1_table_offset = header->l1_table_offset;
 
        /*allocate a 4Kbyte multiple of memory*/
        l1_table_size = s->l1_size * sizeof(uint64_t);
        if (l1_table_size % 4096 > 0) {
-               l1_table_size = ((l1_table_size >> 12) + 1) << 12;
+               l1_table_size = ROUNDUP(l1_table_size, 4096);
        }
        ret = posix_memalign((void **)&s->l1_table, 4096, l1_table_size);
        if (ret != 0) goto fail;
@@ -821,7 +821,7 @@ static int tdqcow_open (struct disk_driv
 
        lseek(fd, 0, SEEK_SET);
        l1_table_block = l1_table_size + s->l1_table_offset;
-       l1_table_block = l1_table_block + 512 - (l1_table_block % 512); 
+       l1_table_block = ROUNDUP(l1_table_block, 512);
        ret = posix_memalign((void **)&buf2, 4096, l1_table_block);
        if (ret != 0) goto fail;
        if (read(fd, buf2, l1_table_block) != l1_table_block)
@@ -1226,11 +1226,11 @@ int qcow_create(const char *filename, ui
        
        header_size = (header_size + 7) & ~7;
        if (header_size % 4096 > 0) {
-               header_size = ((header_size >> 12) + 1) << 12;
+               header_size = ROUNDUP(header_size, 4096);
        }
 
        shift = header.cluster_bits + header.l2_bits;
-       l1_size = ((size * 512) + (1LL << shift) - 1) >> shift;
+       l1_size = ROUNDUP(size * 512, 1LL << shift);
 
        header.l1_table_offset = cpu_to_be64(header_size);
        DPRINTF("L1 Table offset: %d, size %d\n",

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