RE: [PATCH] cciss: Fix warnings (and bug on 1TB discs)

Miller, Mike (OS Dev)
2006-10-20T14:53:49Z

>
> On Thu, Oct 19, 2006 at 09:23:36PM -0600, Matthew Wilcox wrote:
> > CCISS was producing warnings about shifts being greater
> than the size
> > of the type and pointers being of incompatible type. Turns
> out this
> > is because it's calling do_div on a 32-bit quantity. Upon further
> > investigation, the sector_t total_size is being assigned to an int,
> > and then we're calling do_div on that int. Obviously,
> sector_div is
> > called for here, and I took the chance to refactor the code
> a little.
>
> Oops, forgot:
> Signed-off-by: Matthew Wilcox <matthew@wil.cx>

Acked-by: Mike Miller <mike.miller@hp.com>

>
> > diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index
> > dcccaf2..bc66026 100644
> > --- a/drivers/block/cciss.c
> > +++ b/drivers/block/cciss.c
> > @@ -1923,7 +1923,6 @@ static void cciss_geometry_inquiry(int c {
> > int return_code;
> > unsigned long t;
> > - unsigned long rem;
> >
> > memset(inq_buff, 0, sizeof(InquiryData_struct));
> > if (withirq)
> > @@ -1939,26 +1938,23 @@ static void cciss_geometry_inquiry(int c
> > printk(KERN_WARNING
> > "cciss: reading geometry failed, volume "
> > "does not support reading geometry\n");
> > - drv->block_size = block_size;
> > - drv->nr_blocks = total_size;
> > drv->heads = 255;
> > drv->sectors = 32; // Sectors per track
> > - t = drv->heads * drv->sectors;
> > - drv->cylinders = total_size;
> > - rem = do_div(drv->cylinders, t);
> > } else {
> > - drv->block_size = block_size;
> > - drv->nr_blocks = total_size;
> > drv->heads = inq_buff->data_byte[6];
> > drv->sectors = inq_buff->data_byte[7];
> > drv->cylinders =
> (inq_buff->data_byte[4] & 0xff) << 8;
> > drv->cylinders += inq_buff->data_byte[5];
> > drv->raid_level = inq_buff->data_byte[8];
> > - t = drv->heads * drv->sectors;
> > - if (t > 1) {
> > - drv->cylinders = total_size;
> > - rem = do_div(drv->cylinders, t);
> > - }
> > + }
> > + drv->block_size = block_size;
> > + drv->nr_blocks = total_size;
> > + t = drv->heads * drv->sectors;
> > + if (t > 1) {
> > + unsigned rem = sector_div(total_size, t);
> > + if (rem)
> > + total_size++;
> > + drv->cylinders = total_size;
> > }
> > } else { /* Get geometry failed */
> > printk(KERN_WARNING "cciss: reading geometry failed\n");
> > -
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