On Fri, Jun 13 2008, Matthew Wilcox wrote:
> On Fri, Jun 13, 2008 at 09:33:27PM +0200, Adel Gadllah wrote:
> > - if (blk_verify_command(rq->cmd, has_write_perm))
> > + if (blk_cmd_filter_verify_command(bd->cmd_filter, rq->cmd, bd->f_mode))
>
> Could you wrap to 80 columns?
>
> > +static ssize_t rcf_cmds_store(struct blk_scsi_cmd_filter *filter,
> > + const char *page, size_t count, int rw)
> > +{
> > + ssize_t ret = 0;
> > + unsigned long okbits[BLK_SCSI_CMD_PER_LONG], *target_okbits;
> > + int cmd, status, len;
> > + substring_t ss;
> > +
> > + memset(&okbits, 0, sizeof (okbits));
> > +
> > + for (len = strlen(page); len > 0; len -= 3) {
> > + if (len < 2)
> > + break;
> > + ss.from = (char *) page + ret;
> > + ss.to = (char *) page + ret + 2;
> > + ret+=3;
> > + status = match_hex(&ss, &cmd);
> > + /* either of these cases means invalid input, so do nothing. */
> > + if (status || cmd >= BLK_SCSI_MAX_CMDS)
> > + return -EINVAL;
> > +
> > + set_bit(cmd, okbits);
>
> set_bit is atomic. locked ops can be quite painful on some processors.
> Since okbits is local, the atomicity isn't necessary and you can simply
> use __set_bit.
Which that is strictly true, this is only invoked when someone sets a
new filter for the device. So probably once in the life time of that
kernel boot, hardly performance critical...
--
Jens Axboe
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