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SubjectRe: [patch 21/21] Add ioctl support for EMC Symmetrix Subsystem Control I/O
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On Wed, 2008-10-01 at 07:03 -0400, Christoph Hellwig wrote:
> > +static int dasd_symm_io(struct dasd_device *device, void __user *argp)
> > +{
> > + struct dasd_symmio_parms usrparm;
> > + char *psf_data, *rssd_result;
> > + struct dasd_ccw_req *cqr;
> > + struct ccw1 *ccw;
> > + int rc;
> > +
> > + /* Copy parms from caller */
> > + rc = copy_from_user(&usrparm, argp, sizeof(usrparm)) ? -EFAULT : 0;
> > + if (rc)
> > + goto out;
>
> That style is quite odd, what about the more normal
>
> rc = -EFAULT;
> if (copy_from_user(&usrparm, argp, sizeof(usrparm)))
> goto out;
>
> instead?

Ok, I will change that.

> > + /* alloc I/O data area */
> > + psf_data = kzalloc(usrparm.psf_data_len, GFP_KERNEL | GFP_DMA);
> > + rssd_result = kzalloc(usrparm.rssd_result_len, GFP_KERNEL | GFP_DMA);
> > + if (!psf_data || !rssd_result) {
> > + rc = -ENOMEM;
> > + goto out_free;
> > + }
>
> just check each on individually and do individual unwinding. Makes the
> code a little more easily readable.

Well, matter of taste I would say. Two kzallocs, one check for the
results and just two kfrees if one of the kzallocs failed. I find this
version to be a little more compact and therefore easier to read. If you
insist I will change it ..

> > + /* get syscall header from user space */
> > + rc = copy_from_user(psf_data,
> > + (void __user *)(unsigned long) usrparm.psf_data,
> > + usrparm.psf_data_len) ? -EFAULT : 0;
> > + if (rc)
> > + goto out_free;
>
> Same as the first copy_from_user

Ok.

> > + rc = copy_to_user((void __user *)(unsigned long) usrparm.rssd_result,
> > + rssd_result, usrparm.rssd_result_len) ? -EFAULT : 0;
>
> And here again.

Ok.

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.




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