On Tue, Dec 27, 2022 at 3:06 PM Shunsuke Mie <mie@xxxxxxxxxx> wrote: > > 2022年12月27日(火) 15:04 Jason Wang <jasowang@xxxxxxxxxx>: > > > > On Tue, Dec 27, 2022 at 10:25 AM Shunsuke Mie <mie@xxxxxxxxxx> wrote: > > > > > > struct vringh_iov is defined to hold userland addresses. However, to use > > > common function, __vring_iov, finally the vringh_iov converts to the > > > vringh_kiov with simple cast. It includes compile time check code to make > > > sure it can be cast correctly. > > > > > > To simplify the code, this patch removes the struct vringh_iov and unifies > > > APIs to struct vringh_kiov. > > > > > > Signed-off-by: Shunsuke Mie <mie@xxxxxxxxxx> > > > > While at this, I wonder if we need to go further, that is, switch to > > using an iov iterator instead of a vringh customized one. > I didn't see the iov iterator yet, thank you for informing me. > Is that iov_iter? https://lwn.net/Articles/625077/ Exactly. Thanks > > Thanks > > > > > --- > > > drivers/vhost/vringh.c | 32 ++++++------------------------ > > > include/linux/vringh.h | 45 ++++-------------------------------------- > > > 2 files changed, 10 insertions(+), 67 deletions(-) > > > > > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c > > > index 828c29306565..aa3cd27d2384 100644 > > > --- a/drivers/vhost/vringh.c > > > +++ b/drivers/vhost/vringh.c > > > @@ -691,8 +691,8 @@ EXPORT_SYMBOL(vringh_init_user); > > > * calling vringh_iov_cleanup() to release the memory, even on error! > > > */ > > > int vringh_getdesc_user(struct vringh *vrh, > > > - struct vringh_iov *riov, > > > - struct vringh_iov *wiov, > > > + struct vringh_kiov *riov, > > > + struct vringh_kiov *wiov, > > > bool (*getrange)(struct vringh *vrh, > > > u64 addr, struct vringh_range *r), > > > u16 *head) > > > @@ -708,26 +708,6 @@ int vringh_getdesc_user(struct vringh *vrh, > > > if (err == vrh->vring.num) > > > return 0; > > > > > > - /* We need the layouts to be the identical for this to work */ > > > - BUILD_BUG_ON(sizeof(struct vringh_kiov) != sizeof(struct vringh_iov)); > > > - BUILD_BUG_ON(offsetof(struct vringh_kiov, iov) != > > > - offsetof(struct vringh_iov, iov)); > > > - BUILD_BUG_ON(offsetof(struct vringh_kiov, i) != > > > - offsetof(struct vringh_iov, i)); > > > - BUILD_BUG_ON(offsetof(struct vringh_kiov, used) != > > > - offsetof(struct vringh_iov, used)); > > > - BUILD_BUG_ON(offsetof(struct vringh_kiov, max_num) != > > > - offsetof(struct vringh_iov, max_num)); > > > - BUILD_BUG_ON(sizeof(struct iovec) != sizeof(struct kvec)); > > > - BUILD_BUG_ON(offsetof(struct iovec, iov_base) != > > > - offsetof(struct kvec, iov_base)); > > > - BUILD_BUG_ON(offsetof(struct iovec, iov_len) != > > > - offsetof(struct kvec, iov_len)); > > > - BUILD_BUG_ON(sizeof(((struct iovec *)NULL)->iov_base) > > > - != sizeof(((struct kvec *)NULL)->iov_base)); > > > - BUILD_BUG_ON(sizeof(((struct iovec *)NULL)->iov_len) > > > - != sizeof(((struct kvec *)NULL)->iov_len)); > > > - > > > *head = err; > > > err = __vringh_iov(vrh, *head, (struct vringh_kiov *)riov, > > > (struct vringh_kiov *)wiov, > > > @@ -740,14 +720,14 @@ int vringh_getdesc_user(struct vringh *vrh, > > > EXPORT_SYMBOL(vringh_getdesc_user); > > > > > > /** > > > - * vringh_iov_pull_user - copy bytes from vring_iov. > > > + * vringh_iov_pull_user - copy bytes from vring_kiov. > > > * @riov: the riov as passed to vringh_getdesc_user() (updated as we consume) > > > * @dst: the place to copy. > > > * @len: the maximum length to copy. > > > * > > > * Returns the bytes copied <= len or a negative errno. > > > */ > > > -ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len) > > > +ssize_t vringh_iov_pull_user(struct vringh_kiov *riov, void *dst, size_t len) > > > { > > > return vringh_iov_xfer(NULL, (struct vringh_kiov *)riov, > > > dst, len, xfer_from_user); > > > @@ -755,14 +735,14 @@ ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len) > > > EXPORT_SYMBOL(vringh_iov_pull_user); > > > > > > /** > > > - * vringh_iov_push_user - copy bytes into vring_iov. > > > + * vringh_iov_push_user - copy bytes into vring_kiov. > > > * @wiov: the wiov as passed to vringh_getdesc_user() (updated as we consume) > > > * @src: the place to copy from. > > > * @len: the maximum length to copy. > > > * > > > * Returns the bytes copied <= len or a negative errno. > > > */ > > > -ssize_t vringh_iov_push_user(struct vringh_iov *wiov, > > > +ssize_t vringh_iov_push_user(struct vringh_kiov *wiov, > > > const void *src, size_t len) > > > { > > > return vringh_iov_xfer(NULL, (struct vringh_kiov *)wiov, > > > diff --git a/include/linux/vringh.h b/include/linux/vringh.h > > > index 1991a02c6431..733d948e8123 100644 > > > --- a/include/linux/vringh.h > > > +++ b/include/linux/vringh.h > > > @@ -79,18 +79,6 @@ struct vringh_range { > > > u64 offset; > > > }; > > > > > > -/** > > > - * struct vringh_iov - iovec mangler. > > > - * > > > - * Mangles iovec in place, and restores it. > > > - * Remaining data is iov + i, of used - i elements. > > > - */ > > > -struct vringh_iov { > > > - struct iovec *iov; > > > - size_t consumed; /* Within iov[i] */ > > > - unsigned i, used, max_num; > > > -}; > > > - > > > /** > > > * struct vringh_kiov - kvec mangler. > > > * > > > @@ -113,44 +101,19 @@ int vringh_init_user(struct vringh *vrh, u64 features, > > > vring_avail_t __user *avail, > > > vring_used_t __user *used); > > > > > > -static inline void vringh_iov_init(struct vringh_iov *iov, > > > - struct iovec *iovec, unsigned num) > > > -{ > > > - iov->used = iov->i = 0; > > > - iov->consumed = 0; > > > - iov->max_num = num; > > > - iov->iov = iovec; > > > -} > > > - > > > -static inline void vringh_iov_reset(struct vringh_iov *iov) > > > -{ > > > - iov->iov[iov->i].iov_len += iov->consumed; > > > - iov->iov[iov->i].iov_base -= iov->consumed; > > > - iov->consumed = 0; > > > - iov->i = 0; > > > -} > > > - > > > -static inline void vringh_iov_cleanup(struct vringh_iov *iov) > > > -{ > > > - if (iov->max_num & VRINGH_IOV_ALLOCATED) > > > - kfree(iov->iov); > > > - iov->max_num = iov->used = iov->i = iov->consumed = 0; > > > - iov->iov = NULL; > > > -} > > > - > > > /* Convert a descriptor into iovecs. */ > > > int vringh_getdesc_user(struct vringh *vrh, > > > - struct vringh_iov *riov, > > > - struct vringh_iov *wiov, > > > + struct vringh_kiov *riov, > > > + struct vringh_kiov *wiov, > > > bool (*getrange)(struct vringh *vrh, > > > u64 addr, struct vringh_range *r), > > > u16 *head); > > > > > > /* Copy bytes from readable vsg, consuming it (and incrementing wiov->i). */ > > > -ssize_t vringh_iov_pull_user(struct vringh_iov *riov, void *dst, size_t len); > > > +ssize_t vringh_iov_pull_user(struct vringh_kiov *riov, void *dst, size_t len); > > > > > > /* Copy bytes into writable vsg, consuming it (and incrementing wiov->i). */ > > > -ssize_t vringh_iov_push_user(struct vringh_iov *wiov, > > > +ssize_t vringh_iov_push_user(struct vringh_kiov *wiov, > > > const void *src, size_t len); > > > > > > /* Mark a descriptor as used. */ > > > -- > > > 2.25.1 > > > > > > Best, > Shunsuke >
