[PATCH 2/2] fs: add pread and pwrite functions

[Alexander Aring]

Hi Sascha,

On Mon, Feb 18, 2013 at 11:17:33AM +0100, Sascha Hauer wrote:
> On Sun, Feb 17, 2013 at 10:05:01PM +0100, Alexander Aring wrote:
> > Add pread and pwrite functions.
> > 
> > Split read and write functions to save some space.
> > The functions pread and pwrite saves and sets the file
> > position to a given offset and restore them afterwards.
> > 
> > Signed-off-by: Alexander Aring <alex.aring at gmail.com>
> > ---
> >  fs/fs.c      | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++----------
> >  include/fs.h |  2 ++
> >  2 files changed, 77 insertions(+), 14 deletions(-)
> > 
> > diff --git a/fs/fs.c b/fs/fs.c
> > index 48d1c89..497a2ea 100644
> > --- a/fs/fs.c
> > +++ b/fs/fs.c
> > @@ -754,17 +754,12 @@ int ioctl(int fd, int request, void *buf)
> >  	return ret;
> >  }
> >  
> > -ssize_t read(int fd, void *buf, size_t count)
> > +static ssize_t __read(FILE *f, void *buf, size_t count)
> >  {
> >  	struct device_d *dev;
> >  	struct fs_driver_d *fsdrv;
> > -	FILE *f;
> >  	int ret;
> >  
> > -	if (check_fd(fd))
> > -		return -errno;
> > -
> > -	f = &files[fd];
> >  	dev = f->dev;
> >  
> >  	fsdrv = dev_to_fs_driver(dev);
> > @@ -777,18 +772,34 @@ ssize_t read(int fd, void *buf, size_t count)
> >  
> >  	ret = fsdrv->read(dev, f, buf, count);
> >  
> > -	if (ret > 0)
> > -		f->pos += ret;
> >  	if (ret < 0)
> >  		errno = -ret;
> >  	return ret;
> >  }
> > -EXPORT_SYMBOL(read);
> > +EXPORT_SYMBOL(pread);
> >  
> > -ssize_t write(int fd, const void *buf, size_t count)
> > +ssize_t pread(int fd, void *buf, size_t count, loff_t offset)
> > +{
> > +	loff_t pos;
> > +	FILE *f;
> > +	int ret;
> > +
> > +	if (check_fd(fd))
> > +		return -errno;
> > +
> > +	f = &files[fd];
> > +
> > +	pos = f->pos;
> > +	f->pos = offset;
> > +	ret = __read(f, buf, count);
> > +	f->pos = pos;
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL(pread);
> 
> pread is exported twice with this patch. I fixed this while applying.
>

Ooops, sry. Thanks for applying.

Regards
Alex