Messages in this thread Patch in this message | | | Date | Fri, 4 Apr 2003 02:30:44 +0200 | From | Jörn Engel <> | Subject | Re: [PATCH] reduce stack in cpqarray.c::ida_ioctl() |
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On Thu, 3 April 2003 12:03:08 +0000, Randy.Dunlap wrote: > > Comments on the patch?
Your patch looks just fine. The original code is a bit odd, though. If you want to change that in one go, read on. If not, please ignore this.
> diff -Naur ./drivers/block/cpqarray.c%IDAIOC ./drivers/block/cpqarray.c > --- ./drivers/block/cpqarray.c%IDAIOC 2003-03-24 14:00:03.000000000 -0800 > +++ ./drivers/block/cpqarray.c 2003-04-02 20:05:57.000000000 -0800 > @@ -1021,7 +1021,7 @@ > int diskinfo[4]; > struct hd_geometry *geo = (struct hd_geometry *)arg; > ida_ioctl_t *io = (ida_ioctl_t*)arg; > - ida_ioctl_t my_io; > + ida_ioctl_t *my_io; > > switch(cmd) { > case HDIO_GETGEO: > @@ -1046,11 +1046,19 @@ > return 0; > case IDAPASSTHRU: > if (!capable(CAP_SYS_RAWIO)) return -EPERM; > - if (copy_from_user(&my_io, io, sizeof(my_io))) > - return -EFAULT; > - error = ida_ctlr_ioctl(ctlr, dsk, &my_io); > - if (error) return error; > - return copy_to_user(io, &my_io, sizeof(my_io)) ? -EFAULT : 0; > + my_io = kmalloc(sizeof(ida_ioctl_t), GFP_KERNEL); > + if (!my_io) > + return -ENOMEM; > + if (copy_from_user(my_io, io, sizeof(*my_io))) { > + error = -EFAULT; > + goto iocfree; > + } > + error = ida_ctlr_ioctl(ctlr, dsk, my_io); > + if (error) goto iocfree;
Wouldn't an extra line be nicer?
> + error = copy_to_user(io, my_io, sizeof(*my_io)) ? -EFAULT : 0;
copy_to_user returns the bytes successfully copied. error is set to -EFAULT, if there was actually data transferred?
How about: + error = copy_to_user(io, my_io, sizeof(*my_io)) < sizeof(*my_io) ? -EFAULT : 0;
> + iocfree: > + kfree(my_io); > + return error; > case IDAGETCTLRSIG: > if (!arg) return -EINVAL; > put_user(hba[ctlr]->ctlr_sig, (int*)arg);
Jörn
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