[RFC PATCH v2 5/7] vringh: unify the APIs for all accessors

From: Shunsuke Mie
Date: Thu Feb 02 2023 - 04:10:16 EST

Each vringh memory accessors that are for user, kern and iotlb has own
interfaces that calls common code. But some codes are duplicated and that
becomes loss extendability.

Introduce a struct vringh_ops and provide a common APIs for all accessors.
It can bee easily extended vringh code for new memory accessor and
simplified a caller code.

An affect of this change is small. It is tested with perf, and results are
following:

- original code
$ perf stat --repeat 20 -- nice -n -20 ./vringh_test_retp_origin \
--parallel --eventidx --fast-vringh
Using CPUS 0 and 3
Guest: notified 0, pinged 98040
Host: notified 98040, pinged 0
...

Performance counter stats for 'nice -n -20 ./vringh_test_retp_origin
--parallel --eventidx --fast-vringh' (20 runs):

6,228.33 msec task-clock # 1.004 CPUs utilized (+- 0.05%)
196,110 context-switches # 31.616 K/sec (+- 0.00%)
6 cpu-migrations # 0.967 /sec (+- 2.39%)
205 page-faults # 33.049 /sec (+- 0.46%)
14,218,527,987 cycles # 2.292 GHz (+- 0.05%)
10,342,897,254 instructions # 0.73 insn per cycle (+- 0.02%)
2,310,572,989 branches # 372.500 M/sec (+- 0.03%)
178,273,068 branch-misses # 7.72% of all branches (+- 0.04%)

6.20406 +- 0.00308 seconds time elapsed ( +- 0.05% )

- changed code
$ perf stat --repeat 20 -- nice -n -20 ./vringh_test_retp_patched \
--parallel --eventidx --fast-vringh
Using CPUS 0 and 3
Guest: notified 0, pinged 98040
Host: notified 98040, pinged 0
...

Performance counter stats for 'nice -n -20 ./vringh_test_retp_patched
--parallel --eventidx --fast-vringh' (20 runs):

6,103.94 msec task-clock # 1.001 CPUs utilized (+- 0.03%)
196,125 context-switches # 32.165 K/sec (+- 0.00%)
7 cpu-migrations # 1.148 /sec (+- 1.56%)
196 page-faults # 32.144 /sec (+- 0.41%)
13,933,055,778 cycles # 2.285 GHz (+- 0.03%)
10,309,004,718 instructions # 0.74 insn per cycle (+- 0.03%)
2,368,447,519 branches # 388.425 M/sec (+- 0.04%)
211,364,886 branch-misses # 8.94% of all branches (+- 0.05%)

6.09888 +- 0.00155 seconds time elapsed ( +- 0.03% )

The result of changed code experiment shows an increase of branches and
branch-misses, but number of pages are decremented. As a result, the
elapsed time is getting shorter than original one.

Signed-off-by: Shunsuke Mie <mie@xxxxxxxxxx>
---
drivers/vhost/vringh.c | 667 +++++++++++------------------------------
include/linux/vringh.h | 100 +++---
2 files changed, 225 insertions(+), 542 deletions(-)

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index bcdbde1d484e..46fb315483ed 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -35,15 +35,12 @@ static __printf(1,2) __cold void vringh_bad(const char *fmt, ...)
}

/* Returns vring->num if empty, -ve on error. */
-static inline int __vringh_get_head(const struct vringh *vrh,
- int (*getu16)(const struct vringh *vrh,
- u16 *val, const __virtio16 *p),
- u16 *last_avail_idx)
+static inline int __vringh_get_head(const struct vringh *vrh, u16 *last_avail_idx)
{
u16 avail_idx, i, head;
int err;

- err = getu16(vrh, &avail_idx, &vrh->vring.avail->idx);
+ err = vrh->ops.getu16(vrh, &avail_idx, &vrh->vring.avail->idx);
if (err) {
vringh_bad("Failed to access avail idx at %p",
&vrh->vring.avail->idx);
@@ -58,7 +55,7 @@ static inline int __vringh_get_head(const struct vringh *vrh,

i = *last_avail_idx & (vrh->vring.num - 1);

- err = getu16(vrh, &head, &vrh->vring.avail->ring[i]);
+ err = vrh->ops.getu16(vrh, &head, &vrh->vring.avail->ring[i]);
if (err) {
vringh_bad("Failed to read head: idx %d address %p",
*last_avail_idx, &vrh->vring.avail->ring[i]);
@@ -131,12 +128,10 @@ static inline ssize_t vringh_iov_xfer(struct vringh *vrh,

/* May reduce *len if range is shorter. */
static inline bool range_check(struct vringh *vrh, u64 addr, size_t *len,
- struct vringh_range *range,
- bool (*getrange)(struct vringh *,
- u64, struct vringh_range *))
+ struct vringh_range *range)
{
if (addr < range->start || addr > range->end_incl) {
- if (!getrange(vrh, addr, range))
+ if (!vrh->ops.getrange(vrh, addr, range))
return false;
}
BUG_ON(addr < range->start || addr > range->end_incl);
@@ -165,9 +160,7 @@ static inline bool range_check(struct vringh *vrh, u64 addr, size_t *len,
}

static inline bool no_range_check(struct vringh *vrh, u64 addr, size_t *len,
- struct vringh_range *range,
- bool (*getrange)(struct vringh *,
- u64, struct vringh_range *))
+ struct vringh_range *range)
{
return true;
}
@@ -244,17 +237,7 @@ static u16 __cold return_from_indirect(const struct vringh *vrh, int *up_next,
}

static int slow_copy(struct vringh *vrh, void *dst, const void *src,
- bool (*rcheck)(struct vringh *vrh, u64 addr, size_t *len,
- struct vringh_range *range,
- bool (*getrange)(struct vringh *vrh,
- u64,
- struct vringh_range *)),
- bool (*getrange)(struct vringh *vrh,
- u64 addr,
- struct vringh_range *r),
- struct vringh_range *range,
- int (*copy)(const struct vringh *vrh,
- void *dst, const void *src, size_t len))
+ struct vringh_range *range)
{
size_t part, len = sizeof(struct vring_desc);

@@ -265,10 +248,10 @@ static int slow_copy(struct vringh *vrh, void *dst, const void *src,
part = len;
addr = (u64)(unsigned long)src - range->offset;

- if (!rcheck(vrh, addr, &part, range, getrange))
+ if (!vrh->ops.range_check(vrh, addr, &part, range))
return -EINVAL;

- err = copy(vrh, dst, src, part);
+ err = vrh->ops.copydesc(vrh, dst, src, part);
if (err)
return err;

@@ -279,18 +262,35 @@ static int slow_copy(struct vringh *vrh, void *dst, const void *src,
return 0;
}

+static int __vringh_init(struct vringh *vrh, u64 features, unsigned int num,
+ bool weak_barriers, gfp_t gfp, struct vring_desc *desc,
+ struct vring_avail *avail, struct vring_used *used)
+{
+ /* Sane power of 2 please! */
+ if (!num || num > 0xffff || (num & (num - 1))) {
+ vringh_bad("Bad ring size %u", num);
+ return -EINVAL;
+ }
+
+ vrh->little_endian = (features & (1ULL << VIRTIO_F_VERSION_1));
+ vrh->event_indices = (features & (1 << VIRTIO_RING_F_EVENT_IDX));
+ vrh->weak_barriers = weak_barriers;
+ vrh->completed = 0;
+ vrh->last_avail_idx = 0;
+ vrh->last_used_idx = 0;
+ vrh->vring.num = num;
+ vrh->vring.desc = desc;
+ vrh->vring.avail = avail;
+ vrh->vring.used = used;
+ vrh->desc_gfp = gfp;
+
+ return 0;
+}
+
static inline int
__vringh_iov(struct vringh *vrh, u16 i,
struct vringh_kiov *riov,
- struct vringh_kiov *wiov,
- bool (*rcheck)(struct vringh *vrh, u64 addr, size_t *len,
- struct vringh_range *range,
- bool (*getrange)(struct vringh *, u64,
- struct vringh_range *)),
- bool (*getrange)(struct vringh *, u64, struct vringh_range *),
- gfp_t gfp,
- int (*copy)(const struct vringh *vrh,
- void *dst, const void *src, size_t len))
+ struct vringh_kiov *wiov, gfp_t gfp)
{
int err, count = 0, indirect_count = 0, up_next, desc_max;
struct vring_desc desc, *descs;
@@ -317,10 +317,9 @@ __vringh_iov(struct vringh *vrh, u16 i,
size_t len;

if (unlikely(slow))
- err = slow_copy(vrh, &desc, &descs[i], rcheck, getrange,
- &slowrange, copy);
+ err = slow_copy(vrh, &desc, &descs[i], &slowrange);
else
- err = copy(vrh, &desc, &descs[i], sizeof(desc));
+ err = vrh->ops.copydesc(vrh, &desc, &descs[i], sizeof(desc));
if (unlikely(err))
goto fail;

@@ -330,7 +329,7 @@ __vringh_iov(struct vringh *vrh, u16 i,

/* Make sure it's OK, and get offset. */
len = vringh32_to_cpu(vrh, desc.len);
- if (!rcheck(vrh, a, &len, &range, getrange)) {
+ if (!vrh->ops.range_check(vrh, a, &len, &range)) {
err = -EINVAL;
goto fail;
}
@@ -382,8 +381,7 @@ __vringh_iov(struct vringh *vrh, u16 i,
again:
/* Make sure it's OK, and get offset. */
len = vringh32_to_cpu(vrh, desc.len);
- if (!rcheck(vrh, vringh64_to_cpu(vrh, desc.addr), &len, &range,
- getrange)) {
+ if (!vrh->ops.range_check(vrh, vringh64_to_cpu(vrh, desc.addr), &len, &range)) {
err = -EINVAL;
goto fail;
}
@@ -436,13 +434,7 @@ __vringh_iov(struct vringh *vrh, u16 i,

static inline int __vringh_complete(struct vringh *vrh,
const struct vring_used_elem *used,
- unsigned int num_used,
- int (*putu16)(const struct vringh *vrh,
- __virtio16 *p, u16 val),
- int (*putused)(const struct vringh *vrh,
- struct vring_used_elem *dst,
- const struct vring_used_elem
- *src, unsigned num))
+ unsigned int num_used)
{
struct vring_used *used_ring;
int err;
@@ -456,12 +448,12 @@ static inline int __vringh_complete(struct vringh *vrh,
/* Compiler knows num_used == 1 sometimes, hence extra check */
if (num_used > 1 && unlikely(off + num_used >= vrh->vring.num)) {
u16 part = vrh->vring.num - off;
- err = putused(vrh, &used_ring->ring[off], used, part);
+ err = vrh->ops.putused(vrh, &used_ring->ring[off], used, part);
if (!err)
- err = putused(vrh, &used_ring->ring[0], used + part,
+ err = vrh->ops.putused(vrh, &used_ring->ring[0], used + part,
num_used - part);
} else
- err = putused(vrh, &used_ring->ring[off], used, num_used);
+ err = vrh->ops.putused(vrh, &used_ring->ring[off], used, num_used);

if (err) {
vringh_bad("Failed to write %u used entries %u at %p",
@@ -472,7 +464,7 @@ static inline int __vringh_complete(struct vringh *vrh,
/* Make sure buffer is written before we update index. */
virtio_wmb(vrh->weak_barriers);

- err = putu16(vrh, &vrh->vring.used->idx, used_idx + num_used);
+ err = vrh->ops.putu16(vrh, &vrh->vring.used->idx, used_idx + num_used);
if (err) {
vringh_bad("Failed to update used index at %p",
&vrh->vring.used->idx);
@@ -483,11 +475,13 @@ static inline int __vringh_complete(struct vringh *vrh,
return 0;
}

-
-static inline int __vringh_need_notify(struct vringh *vrh,
- int (*getu16)(const struct vringh *vrh,
- u16 *val,
- const __virtio16 *p))
+/**
+ * vringh_need_notify - must we tell the other side about used buffers?
+ * @vrh: the vring we've called vringh_complete() on.
+ *
+ * Returns -errno or 0 if we don't need to tell the other side, 1 if we do.
+ */
+int vringh_need_notify(struct vringh *vrh)
{
bool notify;
u16 used_event;
@@ -501,7 +495,7 @@ static inline int __vringh_need_notify(struct vringh *vrh,
/* Old-style, without event indices. */
if (!vrh->event_indices) {
u16 flags;
- err = getu16(vrh, &flags, &vrh->vring.avail->flags);
+ err = vrh->ops.getu16(vrh, &flags, &vrh->vring.avail->flags);
if (err) {
vringh_bad("Failed to get flags at %p",
&vrh->vring.avail->flags);
@@ -511,7 +505,7 @@ static inline int __vringh_need_notify(struct vringh *vrh,
}

/* Modern: we know when other side wants to know. */
- err = getu16(vrh, &used_event, &vring_used_event(&vrh->vring));
+ err = vrh->ops.getu16(vrh, &used_event, &vring_used_event(&vrh->vring));
if (err) {
vringh_bad("Failed to get used event idx at %p",
&vring_used_event(&vrh->vring));
@@ -530,24 +524,28 @@ static inline int __vringh_need_notify(struct vringh *vrh,
vrh->completed = 0;
return notify;
}
+EXPORT_SYMBOL(vringh_need_notify);

-static inline bool __vringh_notify_enable(struct vringh *vrh,
- int (*getu16)(const struct vringh *vrh,
- u16 *val, const __virtio16 *p),
- int (*putu16)(const struct vringh *vrh,
- __virtio16 *p, u16 val))
+/**
+ * vringh_notify_enable - we want to know if something changes.
+ * @vrh: the vring.
+ *
+ * This always enables notifications, but returns false if there are
+ * now more buffers available in the vring.
+ */
+bool vringh_notify_enable(struct vringh *vrh)
{
u16 avail;

if (!vrh->event_indices) {
/* Old-school; update flags. */
- if (putu16(vrh, &vrh->vring.used->flags, 0) != 0) {
+ if (vrh->ops.putu16(vrh, &vrh->vring.used->flags, 0) != 0) {
vringh_bad("Clearing used flags %p",
&vrh->vring.used->flags);
return true;
}
} else {
- if (putu16(vrh, &vring_avail_event(&vrh->vring),
+ if (vrh->ops.putu16(vrh, &vring_avail_event(&vrh->vring),
vrh->last_avail_idx) != 0) {
vringh_bad("Updating avail event index %p",
&vring_avail_event(&vrh->vring));
@@ -559,7 +557,7 @@ static inline bool __vringh_notify_enable(struct vringh *vrh,
* sure it's written, then check again. */
virtio_mb(vrh->weak_barriers);

- if (getu16(vrh, &avail, &vrh->vring.avail->idx) != 0) {
+ if (vrh->ops.getu16(vrh, &avail, &vrh->vring.avail->idx) != 0) {
vringh_bad("Failed to check avail idx at %p",
&vrh->vring.avail->idx);
return true;
@@ -570,20 +568,27 @@ static inline bool __vringh_notify_enable(struct vringh *vrh,
* notification anyway). */
return avail == vrh->last_avail_idx;
}
+EXPORT_SYMBOL(vringh_notify_enable);

-static inline void __vringh_notify_disable(struct vringh *vrh,
- int (*putu16)(const struct vringh *vrh,
- __virtio16 *p, u16 val))
+/**
+ * vringh_notify_disable - don't tell us if something changes.
+ * @vrh: the vring.
+ *
+ * This is our normal running state: we disable and then only enable when
+ * we're going to sleep.
+ */
+void vringh_notify_disable(struct vringh *vrh)
{
if (!vrh->event_indices) {
/* Old-school; update flags. */
- if (putu16(vrh, &vrh->vring.used->flags,
+ if (vrh->ops.putu16(vrh, &vrh->vring.used->flags,
VRING_USED_F_NO_NOTIFY)) {
vringh_bad("Setting used flags %p",
&vrh->vring.used->flags);
}
}
}
+EXPORT_SYMBOL(vringh_notify_disable);

/* Userspace access helpers: in this case, addresses are really userspace. */
static inline int getu16_user(const struct vringh *vrh, u16 *val, const __virtio16 *p)
@@ -630,6 +635,16 @@ static inline int xfer_to_user(const struct vringh *vrh,
-EFAULT : 0;
}

+static struct vringh_ops user_vringh_ops = {
+ .getu16 = getu16_user,
+ .putu16 = putu16_user,
+ .xfer_from = xfer_from_user,
+ .xfer_to = xfer_to_user,
+ .putused = putused_user,
+ .copydesc = copydesc_user,
+ .range_check = range_check,
+};
+
/**
* vringh_init_user - initialize a vringh for a userspace vring.
* @vrh: the vringh to initialize.
@@ -639,6 +654,7 @@ static inline int xfer_to_user(const struct vringh *vrh,
* @desc: the userpace descriptor pointer.
* @avail: the userpace avail pointer.
* @used: the userpace used pointer.
+ * @getrange: a function that return a range that vring can access.
*
* Returns an error if num is invalid: you should check pointers
* yourself!
@@ -647,36 +663,32 @@ int vringh_init_user(struct vringh *vrh, u64 features,
unsigned int num, bool weak_barriers,
vring_desc_t __user *desc,
vring_avail_t __user *avail,
- vring_used_t __user *used)
+ vring_used_t __user *used,
+ bool (*getrange)(struct vringh *vrh, u64 addr, struct vringh_range *r))
{
- /* Sane power of 2 please! */
- if (!num || num > 0xffff || (num & (num - 1))) {
- vringh_bad("Bad ring size %u", num);
- return -EINVAL;
- }
+ int err;
+
+ err = __vringh_init(vrh, features, num, weak_barriers, GFP_KERNEL,
+ (__force struct vring_desc *)desc,
+ (__force struct vring_avail *)avail,
+ (__force struct vring_used *)used);
+ if (err)
+ return err;
+
+ memcpy(&vrh->ops, &user_vringh_ops, sizeof(user_vringh_ops));
+ vrh->ops.getrange = getrange;

- vrh->little_endian = (features & (1ULL << VIRTIO_F_VERSION_1));
- vrh->event_indices = (features & (1 << VIRTIO_RING_F_EVENT_IDX));
- vrh->weak_barriers = weak_barriers;
- vrh->completed = 0;
- vrh->last_avail_idx = 0;
- vrh->last_used_idx = 0;
- vrh->vring.num = num;
- /* vring expects kernel addresses, but only used via accessors. */
- vrh->vring.desc = (__force struct vring_desc *)desc;
- vrh->vring.avail = (__force struct vring_avail *)avail;
- vrh->vring.used = (__force struct vring_used *)used;
return 0;
}
EXPORT_SYMBOL(vringh_init_user);

/**
- * vringh_getdesc_user - get next available descriptor from userspace ring.
- * @vrh: the userspace vring.
+ * vringh_getdesc - get next available descriptor from ring.
+ * @vrh: the vringh to get desc.
* @riov: where to put the readable descriptors (or NULL)
* @wiov: where to put the writable descriptors (or NULL)
* @getrange: function to call to check ranges.
- * @head: head index we received, for passing to vringh_complete_user().
+ * @head: head index we received, for passing to vringh_complete().
*
* Returns 0 if there was no descriptor, 1 if there was, or -errno.
*
@@ -690,17 +702,15 @@ EXPORT_SYMBOL(vringh_init_user);
* When you don't have to use riov and wiov anymore, you should clean up them
* calling vringh_iov_cleanup() to release the memory, even on error!
*/
-int vringh_getdesc_user(struct vringh *vrh,
+int vringh_getdesc(struct vringh *vrh,
struct vringh_kiov *riov,
struct vringh_kiov *wiov,
- bool (*getrange)(struct vringh *vrh,
- u64 addr, struct vringh_range *r),
u16 *head)
{
int err;

*head = vrh->vring.num;
- err = __vringh_get_head(vrh, getu16_user, &vrh->last_avail_idx);
+ err = __vringh_get_head(vrh, &vrh->last_avail_idx);
if (err < 0)
return err;

@@ -709,137 +719,100 @@ int vringh_getdesc_user(struct vringh *vrh,
return 0;

*head = err;
- err = __vringh_iov(vrh, *head, (struct vringh_kiov *)riov,
- (struct vringh_kiov *)wiov,
- range_check, getrange, GFP_KERNEL, copydesc_user);
+ err = __vringh_iov(vrh, *head, riov, wiov, GFP_KERNEL);
if (err)
return err;

return 1;
}
-EXPORT_SYMBOL(vringh_getdesc_user);
+EXPORT_SYMBOL(vringh_getdesc);

/**
- * vringh_iov_pull_user - copy bytes from vring_kiov.
- * @riov: the riov as passed to vringh_getdesc_user() (updated as we consume)
+ * vringh_iov_pull - copy bytes from vring_kiov.
+ * @vrh: the vringh to load data.
+ * @riov: the riov as passed to vringh_getdesc() (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_kiov *riov, void *dst, size_t len)
+ssize_t vringh_iov_pull(struct vringh *vrh, struct vringh_kiov *riov, void *dst, size_t len)
{
return vringh_iov_xfer(NULL, (struct vringh_kiov *)riov,
- dst, len, xfer_from_user);
+ dst, len, vrh->ops.xfer_from);
}
-EXPORT_SYMBOL(vringh_iov_pull_user);
+EXPORT_SYMBOL(vringh_iov_pull);

/**
- * vringh_iov_push_user - copy bytes into vring_kiov.
- * @wiov: the wiov as passed to vringh_getdesc_user() (updated as we consume)
+ * vringh_iov_push - copy bytes into vring_kiov.
+ * @vrh: the vringh to store data.
+ * @wiov: the wiov as passed to vringh_getdesc() (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_kiov *wiov,
+ssize_t vringh_iov_push(struct vringh *vrh, struct vringh_kiov *wiov,
const void *src, size_t len)
{
return vringh_iov_xfer(NULL, (struct vringh_kiov *)wiov,
- (void *)src, len, xfer_to_user);
+ (void *)src, len, vrh->ops.xfer_to);
}
-EXPORT_SYMBOL(vringh_iov_push_user);
+EXPORT_SYMBOL(vringh_iov_push);

/**
- * vringh_abandon_user - we've decided not to handle the descriptor(s).
+ * vringh_abandon - we've decided not to handle the descriptor(s).
* @vrh: the vring.
* @num: the number of descriptors to put back (ie. num
* vringh_get_user() to undo).
*
* The next vringh_get_user() will return the old descriptor(s) again.
*/
-void vringh_abandon_user(struct vringh *vrh, unsigned int num)
+void vringh_abandon(struct vringh *vrh, unsigned int num)
{
/* We only update vring_avail_event(vr) when we want to be notified,
* so we haven't changed that yet. */
vrh->last_avail_idx -= num;
}
-EXPORT_SYMBOL(vringh_abandon_user);
+EXPORT_SYMBOL(vringh_abandon);

/**
- * vringh_complete_user - we've finished with descriptor, publish it.
+ * vringh_complete - we've finished with descriptor, publish it.
* @vrh: the vring.
- * @head: the head as filled in by vringh_getdesc_user.
+ * @head: the head as filled in by vringh_getdesc.
* @len: the length of data we have written.
*
- * You should check vringh_need_notify_user() after one or more calls
+ * You should check vringh_need_notify() after one or more calls
* to this function.
*/
-int vringh_complete_user(struct vringh *vrh, u16 head, u32 len)
+int vringh_complete(struct vringh *vrh, u16 head, u32 len)
{
struct vring_used_elem used;

used.id = cpu_to_vringh32(vrh, head);
used.len = cpu_to_vringh32(vrh, len);
- return __vringh_complete(vrh, &used, 1, putu16_user, putused_user);
+ return __vringh_complete(vrh, &used, 1);
}
-EXPORT_SYMBOL(vringh_complete_user);
+EXPORT_SYMBOL(vringh_complete);

/**
- * vringh_complete_multi_user - we've finished with many descriptors.
+ * vringh_complete_multi - we've finished with many descriptors.
* @vrh: the vring.
* @used: the head, length pairs.
* @num_used: the number of used elements.
*
- * You should check vringh_need_notify_user() after one or more calls
+ * You should check vringh_need_notify() after one or more calls
* to this function.
*/
-int vringh_complete_multi_user(struct vringh *vrh,
+int vringh_complete_multi(struct vringh *vrh,
const struct vring_used_elem used[],
unsigned num_used)
{
- return __vringh_complete(vrh, used, num_used,
- putu16_user, putused_user);
-}
-EXPORT_SYMBOL(vringh_complete_multi_user);
-
-/**
- * vringh_notify_enable_user - we want to know if something changes.
- * @vrh: the vring.
- *
- * This always enables notifications, but returns false if there are
- * now more buffers available in the vring.
- */
-bool vringh_notify_enable_user(struct vringh *vrh)
-{
- return __vringh_notify_enable(vrh, getu16_user, putu16_user);
+ return __vringh_complete(vrh, used, num_used);
}
-EXPORT_SYMBOL(vringh_notify_enable_user);
+EXPORT_SYMBOL(vringh_complete_multi);

-/**
- * vringh_notify_disable_user - don't tell us if something changes.
- * @vrh: the vring.
- *
- * This is our normal running state: we disable and then only enable when
- * we're going to sleep.
- */
-void vringh_notify_disable_user(struct vringh *vrh)
-{
- __vringh_notify_disable(vrh, putu16_user);
-}
-EXPORT_SYMBOL(vringh_notify_disable_user);

-/**
- * vringh_need_notify_user - must we tell the other side about used buffers?
- * @vrh: the vring we've called vringh_complete_user() on.
- *
- * Returns -errno or 0 if we don't need to tell the other side, 1 if we do.
- */
-int vringh_need_notify_user(struct vringh *vrh)
-{
- return __vringh_need_notify(vrh, getu16_user);
-}
-EXPORT_SYMBOL(vringh_need_notify_user);

/* Kernelspace access helpers. */
static inline int getu16_kern(const struct vringh *vrh,
@@ -885,6 +858,17 @@ static inline int kern_xfer(const struct vringh *vrh, void *dst,
return 0;
}

+static const struct vringh_ops kern_vringh_ops = {
+ .getu16 = getu16_kern,
+ .putu16 = putu16_kern,
+ .xfer_from = xfer_kern,
+ .xfer_to = xfer_kern,
+ .putused = putused_kern,
+ .copydesc = copydesc_kern,
+ .range_check = no_range_check,
+ .getrange = NULL,
+};
+
/**
* vringh_init_kern - initialize a vringh for a kernelspace vring.
* @vrh: the vringh to initialize.
@@ -898,179 +882,22 @@ static inline int kern_xfer(const struct vringh *vrh, void *dst,
* Returns an error if num is invalid.
*/
int vringh_init_kern(struct vringh *vrh, u64 features,
- unsigned int num, bool weak_barriers,
+ unsigned int num, bool weak_barriers, gfp_t gfp,
struct vring_desc *desc,
struct vring_avail *avail,
struct vring_used *used)
-{
- /* Sane power of 2 please! */
- if (!num || num > 0xffff || (num & (num - 1))) {
- vringh_bad("Bad ring size %u", num);
- return -EINVAL;
- }
-
- vrh->little_endian = (features & (1ULL << VIRTIO_F_VERSION_1));
- vrh->event_indices = (features & (1 << VIRTIO_RING_F_EVENT_IDX));
- vrh->weak_barriers = weak_barriers;
- vrh->completed = 0;
- vrh->last_avail_idx = 0;
- vrh->last_used_idx = 0;
- vrh->vring.num = num;
- vrh->vring.desc = desc;
- vrh->vring.avail = avail;
- vrh->vring.used = used;
- return 0;
-}
-EXPORT_SYMBOL(vringh_init_kern);
-
-/**
- * vringh_getdesc_kern - get next available descriptor from kernelspace ring.
- * @vrh: the kernelspace vring.
- * @riov: where to put the readable descriptors (or NULL)
- * @wiov: where to put the writable descriptors (or NULL)
- * @head: head index we received, for passing to vringh_complete_kern().
- * @gfp: flags for allocating larger riov/wiov.
- *
- * Returns 0 if there was no descriptor, 1 if there was, or -errno.
- *
- * Note that on error return, you can tell the difference between an
- * invalid ring and a single invalid descriptor: in the former case,
- * *head will be vrh->vring.num. You may be able to ignore an invalid
- * descriptor, but there's not much you can do with an invalid ring.
- *
- * Note that you can reuse riov and wiov with subsequent calls. Content is
- * overwritten and memory reallocated if more space is needed.
- * When you don't have to use riov and wiov anymore, you should clean up them
- * calling vringh_kiov_cleanup() to release the memory, even on error!
- */
-int vringh_getdesc_kern(struct vringh *vrh,
- struct vringh_kiov *riov,
- struct vringh_kiov *wiov,
- u16 *head,
- gfp_t gfp)
{
int err;

- err = __vringh_get_head(vrh, getu16_kern, &vrh->last_avail_idx);
- if (err < 0)
- return err;
-
- /* Empty... */
- if (err == vrh->vring.num)
- return 0;
-
- *head = err;
- err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL,
- gfp, copydesc_kern);
+ err = __vringh_init(vrh, features, num, weak_barriers, gfp, desc, avail, used);
if (err)
return err;

- return 1;
-}
-EXPORT_SYMBOL(vringh_getdesc_kern);
-
-/**
- * vringh_iov_pull_kern - copy bytes from vring_iov.
- * @riov: the riov as passed to vringh_getdesc_kern() (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_kern(struct vringh_kiov *riov, void *dst, size_t len)
-{
- return vringh_iov_xfer(NULL, riov, dst, len, xfer_kern);
-}
-EXPORT_SYMBOL(vringh_iov_pull_kern);
-
-/**
- * vringh_iov_push_kern - copy bytes into vring_iov.
- * @wiov: the wiov as passed to vringh_getdesc_kern() (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_kern(struct vringh_kiov *wiov,
- const void *src, size_t len)
-{
- return vringh_iov_xfer(NULL, wiov, (void *)src, len, kern_xfer);
-}
-EXPORT_SYMBOL(vringh_iov_push_kern);
+ memcpy(&vrh->ops, &kern_vringh_ops, sizeof(kern_vringh_ops));

-/**
- * vringh_abandon_kern - we've decided not to handle the descriptor(s).
- * @vrh: the vring.
- * @num: the number of descriptors to put back (ie. num
- * vringh_get_kern() to undo).
- *
- * The next vringh_get_kern() will return the old descriptor(s) again.
- */
-void vringh_abandon_kern(struct vringh *vrh, unsigned int num)
-{
- /* We only update vring_avail_event(vr) when we want to be notified,
- * so we haven't changed that yet. */
- vrh->last_avail_idx -= num;
-}
-EXPORT_SYMBOL(vringh_abandon_kern);
-
-/**
- * vringh_complete_kern - we've finished with descriptor, publish it.
- * @vrh: the vring.
- * @head: the head as filled in by vringh_getdesc_kern.
- * @len: the length of data we have written.
- *
- * You should check vringh_need_notify_kern() after one or more calls
- * to this function.
- */
-int vringh_complete_kern(struct vringh *vrh, u16 head, u32 len)
-{
- struct vring_used_elem used;
-
- used.id = cpu_to_vringh32(vrh, head);
- used.len = cpu_to_vringh32(vrh, len);
-
- return __vringh_complete(vrh, &used, 1, putu16_kern, putused_kern);
-}
-EXPORT_SYMBOL(vringh_complete_kern);
-
-/**
- * vringh_notify_enable_kern - we want to know if something changes.
- * @vrh: the vring.
- *
- * This always enables notifications, but returns false if there are
- * now more buffers available in the vring.
- */
-bool vringh_notify_enable_kern(struct vringh *vrh)
-{
- return __vringh_notify_enable(vrh, getu16_kern, putu16_kern);
-}
-EXPORT_SYMBOL(vringh_notify_enable_kern);
-
-/**
- * vringh_notify_disable_kern - don't tell us if something changes.
- * @vrh: the vring.
- *
- * This is our normal running state: we disable and then only enable when
- * we're going to sleep.
- */
-void vringh_notify_disable_kern(struct vringh *vrh)
-{
- __vringh_notify_disable(vrh, putu16_kern);
-}
-EXPORT_SYMBOL(vringh_notify_disable_kern);
-
-/**
- * vringh_need_notify_kern - must we tell the other side about used buffers?
- * @vrh: the vring we've called vringh_complete_kern() on.
- *
- * Returns -errno or 0 if we don't need to tell the other side, 1 if we do.
- */
-int vringh_need_notify_kern(struct vringh *vrh)
-{
- return __vringh_need_notify(vrh, getu16_kern);
+ return 0;
}
-EXPORT_SYMBOL(vringh_need_notify_kern);
+EXPORT_SYMBOL(vringh_init_kern);

#if IS_REACHABLE(CONFIG_VHOST_IOTLB)

@@ -1122,7 +949,7 @@ static int iotlb_translate(const struct vringh *vrh,
return ret;
}

-static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
+static int copy_from_iotlb(const struct vringh *vrh, void *dst,
void *src, size_t len)
{
u64 total_translated = 0;
@@ -1155,7 +982,7 @@ static inline int copy_from_iotlb(const struct vringh *vrh, void *dst,
return total_translated;
}

-static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
+static int copy_to_iotlb(const struct vringh *vrh, void *dst,
void *src, size_t len)
{
u64 total_translated = 0;
@@ -1188,7 +1015,7 @@ static inline int copy_to_iotlb(const struct vringh *vrh, void *dst,
return total_translated;
}

-static inline int getu16_iotlb(const struct vringh *vrh,
+static int getu16_iotlb(const struct vringh *vrh,
u16 *val, const __virtio16 *p)
{
struct bio_vec iov;
@@ -1209,7 +1036,7 @@ static inline int getu16_iotlb(const struct vringh *vrh,
return 0;
}

-static inline int putu16_iotlb(const struct vringh *vrh,
+static int putu16_iotlb(const struct vringh *vrh,
__virtio16 *p, u16 val)
{
struct bio_vec iov;
@@ -1230,7 +1057,7 @@ static inline int putu16_iotlb(const struct vringh *vrh,
return 0;
}

-static inline int copydesc_iotlb(const struct vringh *vrh,
+static int copydesc_iotlb(const struct vringh *vrh,
void *dst, const void *src, size_t len)
{
int ret;
@@ -1242,7 +1069,7 @@ static inline int copydesc_iotlb(const struct vringh *vrh,
return 0;
}

-static inline int xfer_from_iotlb(const struct vringh *vrh, void *src,
+static int xfer_from_iotlb(const struct vringh *vrh, void *src,
void *dst, size_t len)
{
int ret;
@@ -1254,7 +1081,7 @@ static inline int xfer_from_iotlb(const struct vringh *vrh, void *src,
return 0;
}

-static inline int xfer_to_iotlb(const struct vringh *vrh,
+static int xfer_to_iotlb(const struct vringh *vrh,
void *dst, void *src, size_t len)
{
int ret;
@@ -1266,7 +1093,7 @@ static inline int xfer_to_iotlb(const struct vringh *vrh,
return 0;
}

-static inline int putused_iotlb(const struct vringh *vrh,
+static int putused_iotlb(const struct vringh *vrh,
struct vring_used_elem *dst,
const struct vring_used_elem *src,
unsigned int num)
@@ -1281,6 +1108,17 @@ static inline int putused_iotlb(const struct vringh *vrh,
return 0;
}

+static const struct vringh_ops iotlb_vringh_ops = {
+ .getu16 = getu16_iotlb,
+ .putu16 = putu16_iotlb,
+ .xfer_from = xfer_from_iotlb,
+ .xfer_to = xfer_to_iotlb,
+ .putused = putused_iotlb,
+ .copydesc = copydesc_iotlb,
+ .range_check = no_range_check,
+ .getrange = NULL,
+};
+
/**
* vringh_init_iotlb - initialize a vringh for a ring with IOTLB.
* @vrh: the vringh to initialize.
@@ -1294,13 +1132,20 @@ static inline int putused_iotlb(const struct vringh *vrh,
* Returns an error if num is invalid.
*/
int vringh_init_iotlb(struct vringh *vrh, u64 features,
- unsigned int num, bool weak_barriers,
+ unsigned int num, bool weak_barriers, gfp_t gfp,
struct vring_desc *desc,
struct vring_avail *avail,
struct vring_used *used)
{
- return vringh_init_kern(vrh, features, num, weak_barriers,
- desc, avail, used);
+ int err;
+
+ err = __vringh_init(vrh, features, num, weak_barriers, gfp, desc, avail, used);
+ if (err)
+ return err;
+
+ memcpy(&vrh->ops, &iotlb_vringh_ops, sizeof(iotlb_vringh_ops));
+
+ return 0;
}
EXPORT_SYMBOL(vringh_init_iotlb);

@@ -1318,162 +1163,6 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
}
EXPORT_SYMBOL(vringh_set_iotlb);

-/**
- * vringh_getdesc_iotlb - get next available descriptor from ring with
- * IOTLB.
- * @vrh: the kernelspace vring.
- * @riov: where to put the readable descriptors (or NULL)
- * @wiov: where to put the writable descriptors (or NULL)
- * @head: head index we received, for passing to vringh_complete_iotlb().
- * @gfp: flags for allocating larger riov/wiov.
- *
- * Returns 0 if there was no descriptor, 1 if there was, or -errno.
- *
- * Note that on error return, you can tell the difference between an
- * invalid ring and a single invalid descriptor: in the former case,
- * *head will be vrh->vring.num. You may be able to ignore an invalid
- * descriptor, but there's not much you can do with an invalid ring.
- *
- * Note that you can reuse riov and wiov with subsequent calls. Content is
- * overwritten and memory reallocated if more space is needed.
- * When you don't have to use riov and wiov anymore, you should clean up them
- * calling vringh_kiov_cleanup() to release the memory, even on error!
- */
-int vringh_getdesc_iotlb(struct vringh *vrh,
- struct vringh_kiov *riov,
- struct vringh_kiov *wiov,
- u16 *head,
- gfp_t gfp)
-{
- int err;
-
- err = __vringh_get_head(vrh, getu16_iotlb, &vrh->last_avail_idx);
- if (err < 0)
- return err;
-
- /* Empty... */
- if (err == vrh->vring.num)
- return 0;
-
- *head = err;
- err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL,
- gfp, copydesc_iotlb);
- if (err)
- return err;
-
- return 1;
-}
-EXPORT_SYMBOL(vringh_getdesc_iotlb);
-
-/**
- * vringh_iov_pull_iotlb - copy bytes from vring_iov.
- * @vrh: the vring.
- * @riov: the riov as passed to vringh_getdesc_iotlb() (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_iotlb(struct vringh *vrh,
- struct vringh_kiov *riov,
- void *dst, size_t len)
-{
- return vringh_iov_xfer(vrh, riov, dst, len, xfer_from_iotlb);
-}
-EXPORT_SYMBOL(vringh_iov_pull_iotlb);
-
-/**
- * vringh_iov_push_iotlb - copy bytes into vring_iov.
- * @vrh: the vring.
- * @wiov: the wiov as passed to vringh_getdesc_iotlb() (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_iotlb(struct vringh *vrh,
- struct vringh_kiov *wiov,
- const void *src, size_t len)
-{
- return vringh_iov_xfer(vrh, wiov, (void *)src, len, xfer_to_iotlb);
-}
-EXPORT_SYMBOL(vringh_iov_push_iotlb);
-
-/**
- * vringh_abandon_iotlb - we've decided not to handle the descriptor(s).
- * @vrh: the vring.
- * @num: the number of descriptors to put back (ie. num
- * vringh_get_iotlb() to undo).
- *
- * The next vringh_get_iotlb() will return the old descriptor(s) again.
- */
-void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num)
-{
- /* We only update vring_avail_event(vr) when we want to be notified,
- * so we haven't changed that yet.
- */
- vrh->last_avail_idx -= num;
-}
-EXPORT_SYMBOL(vringh_abandon_iotlb);
-
-/**
- * vringh_complete_iotlb - we've finished with descriptor, publish it.
- * @vrh: the vring.
- * @head: the head as filled in by vringh_getdesc_iotlb.
- * @len: the length of data we have written.
- *
- * You should check vringh_need_notify_iotlb() after one or more calls
- * to this function.
- */
-int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len)
-{
- struct vring_used_elem used;
-
- used.id = cpu_to_vringh32(vrh, head);
- used.len = cpu_to_vringh32(vrh, len);
-
- return __vringh_complete(vrh, &used, 1, putu16_iotlb, putused_iotlb);
-}
-EXPORT_SYMBOL(vringh_complete_iotlb);
-
-/**
- * vringh_notify_enable_iotlb - we want to know if something changes.
- * @vrh: the vring.
- *
- * This always enables notifications, but returns false if there are
- * now more buffers available in the vring.
- */
-bool vringh_notify_enable_iotlb(struct vringh *vrh)
-{
- return __vringh_notify_enable(vrh, getu16_iotlb, putu16_iotlb);
-}
-EXPORT_SYMBOL(vringh_notify_enable_iotlb);
-
-/**
- * vringh_notify_disable_iotlb - don't tell us if something changes.
- * @vrh: the vring.
- *
- * This is our normal running state: we disable and then only enable when
- * we're going to sleep.
- */
-void vringh_notify_disable_iotlb(struct vringh *vrh)
-{
- __vringh_notify_disable(vrh, putu16_iotlb);
-}
-EXPORT_SYMBOL(vringh_notify_disable_iotlb);
-
-/**
- * vringh_need_notify_iotlb - must we tell the other side about used buffers?
- * @vrh: the vring we've called vringh_complete_iotlb() on.
- *
- * Returns -errno or 0 if we don't need to tell the other side, 1 if we do.
- */
-int vringh_need_notify_iotlb(struct vringh *vrh)
-{
- return __vringh_need_notify(vrh, getu16_iotlb);
-}
-EXPORT_SYMBOL(vringh_need_notify_iotlb);
-
#endif

MODULE_LICENSE("GPL");
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index 733d948e8123..89c73605c85f 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -21,6 +21,36 @@
#endif
#include <asm/barrier.h>

+struct vringh;
+struct vringh_range;
+
+/**
+ * struct vringh_ops - ops for accessing a vring and checking to access range.
+ * @getu16: read u16 value from pointer
+ * @putu16: write u16 value to pointer
+ * @xfer_from: copy memory range from specified address to local virtual address
+ * @xfer_tio: copy memory range from local virtual address to specified address
+ * @putused: update vring used descriptor
+ * @copydesc: copy desiptor from target to local virtual address
+ * @range_check: check if the region is accessible
+ * @getrange: return a range that vring can access
+ */
+struct vringh_ops {
+ int (*getu16)(const struct vringh *vrh, u16 *val, const __virtio16 *p);
+ int (*putu16)(const struct vringh *vrh, __virtio16 *p, u16 val);
+ int (*xfer_from)(const struct vringh *vrh, void *src, void *dst,
+ size_t len);
+ int (*xfer_to)(const struct vringh *vrh, void *dst, void *src,
+ size_t len);
+ int (*putused)(const struct vringh *vrh, struct vring_used_elem *dst,
+ const struct vring_used_elem *src, unsigned int num);
+ int (*copydesc)(const struct vringh *vrh, void *dst, const void *src,
+ size_t len);
+ bool (*range_check)(struct vringh *vrh, u64 addr, size_t *len,
+ struct vringh_range *range);
+ bool (*getrange)(struct vringh *vrh, u64 addr, struct vringh_range *r);
+};
+
/* virtio_ring with information needed for host access. */
struct vringh {
/* Everything is little endian */
@@ -52,6 +82,10 @@ struct vringh {

/* The function to call to notify the guest about added buffers */
void (*notify)(struct vringh *);
+
+ struct vringh_ops ops;
+
+ gfp_t desc_gfp;
};

/**
@@ -99,41 +133,40 @@ int vringh_init_user(struct vringh *vrh, u64 features,
unsigned int num, bool weak_barriers,
vring_desc_t __user *desc,
vring_avail_t __user *avail,
- vring_used_t __user *used);
+ vring_used_t __user *used,
+ bool (*getrange)(struct vringh *vrh, u64 addr, struct vringh_range *r));

/* Convert a descriptor into iovecs. */
-int vringh_getdesc_user(struct vringh *vrh,
+int vringh_getdesc(struct vringh *vrh,
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_kiov *riov, void *dst, size_t len);
+ssize_t vringh_iov_pull(struct vringh *vrh, 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_kiov *wiov,
+ssize_t vringh_iov_push(struct vringh *vrh, struct vringh_kiov *wiov,
const void *src, size_t len);

/* Mark a descriptor as used. */
-int vringh_complete_user(struct vringh *vrh, u16 head, u32 len);
-int vringh_complete_multi_user(struct vringh *vrh,
+int vringh_complete(struct vringh *vrh, u16 head, u32 len);
+int vringh_complete_multi(struct vringh *vrh,
const struct vring_used_elem used[],
unsigned num_used);

/* Pretend we've never seen descriptor (for easy error handling). */
-void vringh_abandon_user(struct vringh *vrh, unsigned int num);
+void vringh_abandon(struct vringh *vrh, unsigned int num);

/* Do we need to fire the eventfd to notify the other side? */
-int vringh_need_notify_user(struct vringh *vrh);
+int vringh_need_notify(struct vringh *vrh);

-bool vringh_notify_enable_user(struct vringh *vrh);
-void vringh_notify_disable_user(struct vringh *vrh);
+bool vringh_notify_enable(struct vringh *vrh);
+void vringh_notify_disable(struct vringh *vrh);

/* Helpers for kernelspace vrings. */
int vringh_init_kern(struct vringh *vrh, u64 features,
- unsigned int num, bool weak_barriers,
+ unsigned int num, bool weak_barriers, gfp_t gfp,
struct vring_desc *desc,
struct vring_avail *avail,
struct vring_used *used);
@@ -176,23 +209,6 @@ static inline size_t vringh_kiov_length(struct vringh_kiov *kiov)

void vringh_kiov_advance(struct vringh_kiov *kiov, size_t len);

-int vringh_getdesc_kern(struct vringh *vrh,
- struct vringh_kiov *riov,
- struct vringh_kiov *wiov,
- u16 *head,
- gfp_t gfp);
-
-ssize_t vringh_iov_pull_kern(struct vringh_kiov *riov, void *dst, size_t len);
-ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
- const void *src, size_t len);
-void vringh_abandon_kern(struct vringh *vrh, unsigned int num);
-int vringh_complete_kern(struct vringh *vrh, u16 head, u32 len);
-
-bool vringh_notify_enable_kern(struct vringh *vrh);
-void vringh_notify_disable_kern(struct vringh *vrh);
-
-int vringh_need_notify_kern(struct vringh *vrh);
-
/* Notify the guest about buffers added to the used ring */
static inline void vringh_notify(struct vringh *vrh)
{
@@ -242,33 +258,11 @@ void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,
spinlock_t *iotlb_lock);

int vringh_init_iotlb(struct vringh *vrh, u64 features,
- unsigned int num, bool weak_barriers,
+ unsigned int num, bool weak_barriers, gfp_t gfp,
struct vring_desc *desc,
struct vring_avail *avail,
struct vring_used *used);

-int vringh_getdesc_iotlb(struct vringh *vrh,
- struct vringh_kiov *riov,
- struct vringh_kiov *wiov,
- u16 *head,
- gfp_t gfp);
-
-ssize_t vringh_iov_pull_iotlb(struct vringh *vrh,
- struct vringh_kiov *riov,
- void *dst, size_t len);
-ssize_t vringh_iov_push_iotlb(struct vringh *vrh,
- struct vringh_kiov *wiov,
- const void *src, size_t len);
-
-void vringh_abandon_iotlb(struct vringh *vrh, unsigned int num);
-
-int vringh_complete_iotlb(struct vringh *vrh, u16 head, u32 len);
-
-bool vringh_notify_enable_iotlb(struct vringh *vrh);
-void vringh_notify_disable_iotlb(struct vringh *vrh);
-
-int vringh_need_notify_iotlb(struct vringh *vrh);
-
#endif /* CONFIG_VHOST_IOTLB */

#endif /* _LINUX_VRINGH_H */
--
2.25.1