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Subject[PATCH 39/49] Staging: poch: Correct pages from bytes.
Date
From: vijaykumar@bravegnu.org <vijaykumar@bravegnu.org>

Accurately calculate the no. of pages from the bytes.

Signed-off-by: Vijay Kumar <vijaykumar@bravegnu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/staging/poch/poch.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/poch/poch.c b/drivers/staging/poch/poch.c
index de3f8c6..52fc3d4 100644
--- a/drivers/staging/poch/poch.c
+++ b/drivers/staging/poch/poch.c
@@ -299,6 +299,14 @@ static ssize_t show_direction(struct device *dev,
}
static DEVICE_ATTR(dir, S_IRUSR|S_IRGRP, show_direction, NULL);

+static unsigned long npages(unsigned long bytes)
+{
+ if (bytes % PAGE_SIZE == 0)
+ return bytes / PAGE_SIZE;
+ else
+ return (bytes / PAGE_SIZE) + 1;
+}
+
static ssize_t show_mmap_size(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -309,10 +317,8 @@ static ssize_t show_mmap_size(struct device *dev,
unsigned long header_pages;
unsigned long total_group_pages;

- /* FIXME: We do not have to add 1, if group_size a multiple of
- PAGE_SIZE. */
- group_pages = (channel->group_size / PAGE_SIZE) + 1;
- header_pages = (channel->header_size / PAGE_SIZE) + 1;
+ group_pages = npages(channel->group_size);
+ header_pages = npages(channel->header_size);
total_group_pages = group_pages * channel->group_count;

mmap_size = (header_pages + total_group_pages) * PAGE_SIZE;
@@ -350,8 +356,8 @@ static int poch_channel_alloc_groups(struct channel_info *channel)
unsigned long group_pages;
unsigned long header_pages;

- group_pages = (channel->group_size / PAGE_SIZE) + 1;
- header_pages = (channel->header_size / PAGE_SIZE) + 1;
+ group_pages = npages(channel->group_size);
+ header_pages = npages(channel->header_size);

for (i = 0; i < channel->group_count; i++) {
struct poch_group_info *group;
@@ -850,8 +856,8 @@ static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
return -EINVAL;
}

- group_pages = (channel->group_size / PAGE_SIZE) + 1;
- header_pages = (channel->header_size / PAGE_SIZE) + 1;
+ group_pages = npages(channel->group_size);
+ header_pages = npages(channel->header_size);
total_group_pages = group_pages * channel->group_count;

size = vma->vm_end - vma->vm_start;
--
1.6.0.2


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