* [PATCH v2] bufio: round up block size to power of 2
@ 2018-04-24 6:13 Michael Chang
2018-04-24 9:39 ` Daniel Kiper
0 siblings, 1 reply; 2+ messages in thread
From: Michael Chang @ 2018-04-24 6:13 UTC (permalink / raw)
To: grub-devel, Daniel Kiper
Rounding up the bufio->block_size to meet power of 2 to facilitate next_buf
calcuation in grub_bufio_read.
Signed-off-by: Michael Chang <mchang@suse.com>
v2:
- Use a more terse approach to round up size suggested by Daniel
- Added comment to explain why to have the size rounded
---
grub-core/io/bufio.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/grub-core/io/bufio.c b/grub-core/io/bufio.c
index 22438277d..75adaa135 100644
--- a/grub-core/io/bufio.c
+++ b/grub-core/io/bufio.c
@@ -61,6 +61,11 @@ grub_bufio_open (grub_file_t io, int size)
size = ((io->size > GRUB_BUFIO_MAX_SIZE) ? GRUB_BUFIO_MAX_SIZE :
io->size);
+ /* round up size to power of 2 to which the binary math to calculate next_buf
+ in grub_bufio_read requires. */
+ while (size & (size - 1))
+ size = (size | (size - 1)) + 1;
+
bufio = grub_zalloc (sizeof (struct grub_bufio) + size);
if (! bufio)
{
--
2.13.6
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] bufio: round up block size to power of 2
2018-04-24 6:13 [PATCH v2] bufio: round up block size to power of 2 Michael Chang
@ 2018-04-24 9:39 ` Daniel Kiper
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Kiper @ 2018-04-24 9:39 UTC (permalink / raw)
To: Michael Chang; +Cc: grub-devel, Daniel Kiper
On Tue, Apr 24, 2018 at 02:13:04PM +0800, Michael Chang wrote:
> Rounding up the bufio->block_size to meet power of 2 to facilitate next_buf
> calcuation in grub_bufio_read.
>
> Signed-off-by: Michael Chang <mchang@suse.com>
>
> v2:
Next time please put "---" before "v2:" just after SOB.
This way git am will not pull v2 changes description into
commit message. Otherwise it looks good to me. If there
are no objections I will commit this in a week or so.
Daniel
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