Author: sephe Date: Wed Jul 27 07:36:54 2016 New Revision: 303370 URL: https://svnweb.freebsd.org/changeset/base/303370
Log: hyperv/vmbus: Cleanup RX bufring read process. MFC after: 1 week Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D7317 Modified: head/sys/dev/hyperv/vmbus/hv_ring_buffer.c head/sys/dev/hyperv/vmbus/vmbus_brvar.h Modified: head/sys/dev/hyperv/vmbus/hv_ring_buffer.c ============================================================================== --- head/sys/dev/hyperv/vmbus/hv_ring_buffer.c Wed Jul 27 07:19:06 2016 (r303369) +++ head/sys/dev/hyperv/vmbus/hv_ring_buffer.c Wed Jul 27 07:36:54 2016 (r303370) @@ -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_txb 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, 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, /* * 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, 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); -} Modified: head/sys/dev/hyperv/vmbus/vmbus_brvar.h ============================================================================== --- head/sys/dev/hyperv/vmbus/vmbus_brvar.h Wed Jul 27 07:19:06 2016 (r303369) +++ head/sys/dev/hyperv/vmbus/vmbus_brvar.h Wed Jul 27 07:36:54 2016 (r303370) @@ -80,7 +80,7 @@ void vmbus_rxbr_deinit(struct vmbus_rxb 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); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
