Jason Wang
2022-Dec-27 06:04 UTC
[RFC PATCH 2/9] vringh: remove vringh_iov and unite to vringh_kiov
On Tue, Dec 27, 2022 at 10:25 AM Shunsuke Mie <mie at igel.co.jp> 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 at igel.co.jp>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. 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 >
Michael S. Tsirkin
2022-Dec-27 07:05 UTC
[RFC PATCH 2/9] vringh: remove vringh_iov and unite to vringh_kiov
On Tue, Dec 27, 2022 at 02:04:03PM +0800, Jason Wang wrote:> On Tue, Dec 27, 2022 at 10:25 AM Shunsuke Mie <mie at igel.co.jp> 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 at igel.co.jp> > > 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. > > ThanksPossibly, but when doing changes like this one needs to be careful to avoid breaking all the inlining tricks vringh relies on for performance. -- MST
Shunsuke Mie
2022-Dec-27 07:05 UTC
[RFC PATCH 2/9] vringh: remove vringh_iov and unite to vringh_kiov
2022?12?27?(?) 15:04 Jason Wang <jasowang at redhat.com>:> > On Tue, Dec 27, 2022 at 10:25 AM Shunsuke Mie <mie at igel.co.jp> 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 at igel.co.jp> > > 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/> 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