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hyperv/vmbus: Cleanup RX bufring read process.

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MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D7317
This commit is contained in:
sephe 2016-07-27 07:36:54 +00:00
parent 7718d7bb79
commit cf9435425a
2 changed files with 42 additions and 59 deletions
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99
sys/dev/hyperv/vmbus/hv_ring_buffer.c
View File

@ -38,8 +38,8 @@
#define VMBUS_BR_WAVAIL(r, w, z) \
(((w) >= (r)) ? ((z) - ((w) - (r))) : ((r) - (w)))
static uint32_t copy_from_ring_buffer(const struct vmbus_rxbr *rbr,
char *dest, uint32_t dest_len, uint32_t start_read_offset);
/* Increase bufing index */
#define VMBUS_BR_IDXINC(idx, inc, sz) (((idx) + (inc)) % (sz))
static int
vmbus_br_sysctl_state(SYSCTL_HANDLER_ARGS)
@ -244,20 +244,15 @@ vmbus_txbr_copyto(const struct vmbus_txbr *tbr, uint32_t windex,
uint32_t br_dsize = tbr->txbr_dsize;
if (cplen > br_dsize - windex) {
uint32_t fraglen;
uint32_t fraglen = br_dsize - windex;
/* Wrap-around detected! */
fraglen = br_dsize - windex;
/* Wrap-around detected */
memcpy(br_data + windex, src, fraglen);
memcpy(br_data, src + fraglen, cplen - fraglen);
} else {
memcpy(br_data + windex, src, cplen);
}
windex += cplen;
windex %= br_dsize;
return windex;
return VMBUS_BR_IDXINC(windex, cplen, br_dsize);
}
/*
@ -331,46 +326,60 @@ vmbus_txbr_write(struct vmbus_txbr *tbr, const struct iovec iov[], int iovlen,
return (0);
}
static __inline uint32_t
vmbus_rxbr_copyfrom(const struct vmbus_rxbr *rbr, uint32_t rindex,
void *dst0, int cplen)
{
uint8_t *dst = dst0;
const uint8_t *br_data = rbr->rxbr_data;
uint32_t br_dsize = rbr->rxbr_dsize;
if (cplen > br_dsize - rindex) {
uint32_t fraglen = br_dsize - rindex;
/* Wrap-around detected. */
memcpy(dst, br_data + rindex, fraglen);
memcpy(dst + fraglen, br_data, cplen - fraglen);
} else {
memcpy(dst, br_data + rindex, cplen);
}
return VMBUS_BR_IDXINC(rindex, cplen, br_dsize);
}
int
vmbus_rxbr_peek(struct vmbus_rxbr *rbr, void *data, int dlen)
{
uint32_t bytesAvailToRead;
uint32_t nextReadLocation = 0;
mtx_lock_spin(&rbr->rxbr_lock);
/*
* The requested data and the 64bits channel packet
* offset should be there at least.
*/
bytesAvailToRead = vmbus_rxbr_avail(rbr);
if (bytesAvailToRead < dlen + sizeof(uint64_t)) {
if (vmbus_rxbr_avail(rbr) < dlen + sizeof(uint64_t)) {
mtx_unlock_spin(&rbr->rxbr_lock);
return (EAGAIN);
}
nextReadLocation = rbr->rxbr_rindex;
nextReadLocation = copy_from_ring_buffer(rbr, data, dlen,
nextReadLocation);
vmbus_rxbr_copyfrom(rbr, rbr->rxbr_rindex, data, dlen);
mtx_unlock_spin(&rbr->rxbr_lock);
return (0);
}
/*
* NOTE:
* We assume (dlen + skip) == sizeof(channel packet).
*/
int
vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t offset)
vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t skip)
{
uint32_t bytes_avail_to_read;
uint32_t next_read_location = 0;
uint64_t prev_indices = 0;
uint32_t rindex, br_dsize = rbr->rxbr_dsize;
KASSERT(dlen > 0, ("invalid dlen %d", dlen));
KASSERT(dlen + skip > 0, ("invalid dlen %d, offset %u", dlen, skip));
mtx_lock_spin(&rbr->rxbr_lock);
bytes_avail_to_read = vmbus_rxbr_avail(rbr);
if (bytes_avail_to_read < dlen + offset + sizeof(prev_indices)) {
if (vmbus_rxbr_avail(rbr) < dlen + skip + sizeof(uint64_t)) {
mtx_unlock_spin(&rbr->rxbr_lock);
return (EAGAIN);
}
@ -378,16 +387,13 @@ vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t offset)
/*
* Copy channel packet from RX bufring.
*/
next_read_location = (rbr->rxbr_rindex + offset) % rbr->rxbr_dsize;
next_read_location = copy_from_ring_buffer(rbr, data, dlen,
next_read_location);
rindex = VMBUS_BR_IDXINC(rbr->rxbr_rindex, skip, br_dsize);
rindex = vmbus_rxbr_copyfrom(rbr, rindex, data, dlen);
/*
* Discard this channel packet's start offset, which is useless
* for us.
* Discard this channel packet's 64bits offset, which is useless to us.
*/
next_read_location = copy_from_ring_buffer(rbr,
(char *)&prev_indices, sizeof(uint64_t), next_read_location);
rindex = VMBUS_BR_IDXINC(rindex, sizeof(uint64_t), br_dsize);
/*
* XXX only compiler fence is needed.
@ -398,34 +404,11 @@ vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen, uint32_t offset)
wmb();
/*
* Update the read index
* Update the read index _after_ the channel packet is fetched.
*/
rbr->rxbr_rindex = next_read_location;
rbr->rxbr_rindex = rindex;
mtx_unlock_spin(&rbr->rxbr_lock);
return (0);
}
static uint32_t
copy_from_ring_buffer(const struct vmbus_rxbr *rbr, char *dest,
uint32_t dest_len, uint32_t start_read_offset)
{
uint32_t fragLen;
char *ring_buffer = rbr->rxbr_data;
uint32_t ring_buffer_size = rbr->rxbr_dsize;
if (dest_len > ring_buffer_size - start_read_offset) {
/* Wrap-around detected at the src */
fragLen = ring_buffer_size - start_read_offset;
memcpy(dest, ring_buffer + start_read_offset, fragLen);
memcpy(dest + fragLen, ring_buffer, dest_len - fragLen);
} else {
memcpy(dest, ring_buffer + start_read_offset, dest_len);
}
start_read_offset += dest_len;
start_read_offset %= ring_buffer_size;
return (start_read_offset);
}

2
sys/dev/hyperv/vmbus/vmbus_brvar.h
View File

@ -80,7 +80,7 @@ void vmbus_rxbr_deinit(struct vmbus_rxbr *rbr);
void vmbus_rxbr_setup(struct vmbus_rxbr *rbr, void *buf, int blen);
int vmbus_rxbr_peek(struct vmbus_rxbr *rbr, void *data, int dlen);
int vmbus_rxbr_read(struct vmbus_rxbr *rbr, void *data, int dlen,
uint32_t offset);
uint32_t skip);
void vmbus_rxbr_intr_mask(struct vmbus_rxbr *rbr);
uint32_t vmbus_rxbr_intr_unmask(struct vmbus_rxbr *rbr);