On Mon, Mar 18, 2019 at 2:18 PM Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote:
>
>
>
> On 18.03.2019 11:28, Hans Holmberg wrote:
> > On Thu, Mar 14, 2019 at 5:11 PM Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote:
> >>
> >> This patch adds the possibility to provide full device path (like
> >> /dev/nvme0n1) when specifying device on top of which pblk instance
> >> should be created/removed.
> >>
> >> This makes creation of targets from nvme-cli (or other ioctl based
> >> tools) more unified with other commands in comparison with current
> >> situation where almost all commands uses full device path with except
> >> of lightnvm creation/removal parameter which uses just 'nvme0n1'
> >> naming convention. After this changes both approach will be valid.
> >>
> >> Signed-off-by: Igor Konopko <igor.j.konopko@xxxxxxxxx>
> >> ---
> >> drivers/lightnvm/core.c | 23 ++++++++++++++++++-----
> >> 1 file changed, 18 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> >> index c01f83b..838c3d8 100644
> >> --- a/drivers/lightnvm/core.c
> >> +++ b/drivers/lightnvm/core.c
> >> @@ -1195,6 +1195,21 @@ void nvm_unregister(struct nvm_dev *dev)
> >> }
> >> EXPORT_SYMBOL(nvm_unregister);
> >>
> >> +#define PREFIX_STR "/dev/"
> >> +static void nvm_normalize_path(char *path)
> >> +{
> >> + path[DISK_NAME_LEN - 1] = '\0';
> >> + if (!memcmp(PREFIX_STR, path,
> >> + sizeof(char) * strlen(PREFIX_STR))) {
> >> + /*
> >> + * User provide name in '/dev/nvme0n1' format,
> >> + * so we need to skip '/dev/' for comparison
> >> + */
> >> + memmove(path, path + sizeof(char) * strlen(PREFIX_STR),
> >> + (DISK_NAME_LEN - strlen(PREFIX_STR)) * sizeof(char));
> >> + }
> >> +}
> >> +
> >
> > I don't like this. Why add string parsing to the kernel? Can't this
> > feature be added to the nvme tool?
>
> Since during target creation/removal in kernel, we already operate on
> strings multiple times (strcmp calls for target types, nvme device,
> target names) my idea was to keep this in the same layer too.
Oh, pardon the terse and rather grumpy review. Let me elaborate:
String parsing is best avoided when possible, and i don't think it's
worth increasing the kernel code size and changing the behavior of the
IOCTL when its fully doable to do this in userspace.
Thanks,
Hans
>
> >
> >> static int __nvm_configure_create(struct nvm_ioctl_create *create)
> >> {
> >> struct nvm_dev *dev;
> >> @@ -1304,9 +1319,9 @@ static long nvm_ioctl_dev_create(struct file *file, void __user *arg)
> >> return -EINVAL;
> >> }
> >>
> >> - create.dev[DISK_NAME_LEN - 1] = '\0';
> >> + nvm_normalize_path(create.dev);
> >> + nvm_normalize_path(create.tgtname);
> >> create.tgttype[NVM_TTYPE_NAME_MAX - 1] = '\0';
> >> - create.tgtname[DISK_NAME_LEN - 1] = '\0';
> >>
> >> if (create.flags != 0) {
> >> __u32 flags = create.flags;
> >> @@ -1333,7 +1348,7 @@ static long nvm_ioctl_dev_remove(struct file *file, void __user *arg)
> >> if (copy_from_user(&remove, arg, sizeof(struct nvm_ioctl_remove)))
> >> return -EFAULT;
> >>
> >> - remove.tgtname[DISK_NAME_LEN - 1] = '\0';
> >> + nvm_normalize_path(remove.tgtname);
> >>
> >> if (remove.flags != 0) {
> >> pr_err("nvm: no flags supported\n");
> >> @@ -1373,8 +1388,6 @@ static long nvm_ioctl_dev_factory(struct file *file, void __user *arg)
> >> if (copy_from_user(&fact, arg, sizeof(struct nvm_ioctl_dev_factory)))
> >> return -EFAULT;
> >>
> >> - fact.dev[DISK_NAME_LEN - 1] = '\0';
> >> -
> >> if (fact.flags & ~(NVM_FACTORY_NR_BITS - 1))
> >> return -EINVAL;
> >>
> >> --
> >> 2.9.5
> >>
