lkml.org 
[lkml]   [2010]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] vhost: correctly set bits of dirty pages
From
Date
When counting pages we should increase it by 1 instead of VHOST_PAGE_SIZE,
and also make log_write() can correctly process the request across
pages with write_address not start at page boundary.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 20 +++++++++-----------
1 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a29d91c..576300b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -884,23 +884,21 @@ static int set_bit_to_user(int nr, void __user *addr)
static int log_write(void __user *log_base,
u64 write_address, u64 write_length)
{
- int r;
- if (!write_length)
- return 0;
- write_address /= VHOST_PAGE_SIZE;
- for (;;) {
+ int r = 0;
+ while (write_length > 0) {
+ u64 l = VHOST_PAGE_SIZE - write_address % VHOST_PAGE_SIZE;
+ u64 write_page = write_address / VHOST_PAGE_SIZE;
u64 base = (u64)(unsigned long)log_base;
- u64 log = base + write_address / 8;
- int bit = write_address % 8;
+ u64 log = base + write_page / 8;
+ int bit = write_page % 8;
if ((u64)(unsigned long)log != log)
return -EFAULT;
r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
if (r < 0)
return r;
- if (write_length <= VHOST_PAGE_SIZE)
- break;
- write_length -= VHOST_PAGE_SIZE;
- write_address += VHOST_PAGE_SIZE;
+ l = min(l, write_length);
+ write_length -= l;
+ write_address += l;
}
return r;
}


\
 
 \ /
  Last update: 2010-11-29 06:49    [W:0.030 / U:22.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site