From 940b68e2c3e4ebf032885203c3970e9649f814af Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 14 Dec 2015 19:02:01 -0800 Subject: Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek() Currently, there is only one user for hv_ringbuffer_read()/ hv_ringbuffer_peak() functions and the usage of these functions is: - insecure as we drop ring_lock between them, someone else (in theory only) can acquire it in between; - non-optimal as we do a number of things (acquire/release the above mentioned lock, calculate available space on the ring, ...) twice and this path is performance-critical. Remove hv_ringbuffer_peek() moving the logic from __vmbus_recvpacket() to hv_ringbuffer_read(). Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/channel.c | 30 ++---------------------------- 1 file changed, 2 insertions(+), 28 deletions(-) (limited to 'drivers/hv/channel.c') diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index dd6de7f..1161d68 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -927,37 +927,11 @@ __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer, u32 bufferlen, u32 *buffer_actual_len, u64 *requestid, bool raw) { - struct vmpacket_descriptor desc; - u32 packetlen; - u32 userlen; int ret; bool signal = false; - *buffer_actual_len = 0; - *requestid = 0; - - - ret = hv_ringbuffer_peek(&channel->inbound, &desc, - sizeof(struct vmpacket_descriptor)); - if (ret != 0) - return 0; - - packetlen = desc.len8 << 3; - if (!raw) - userlen = packetlen - (desc.offset8 << 3); - else - userlen = packetlen; - - *buffer_actual_len = userlen; - - if (userlen > bufferlen) - return -ENOBUFS; - - *requestid = desc.trans_id; - - /* Copy over the packet to the user buffer */ - ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen, - raw ? 0 : desc.offset8 << 3, &signal); + ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen, + buffer_actual_len, requestid, &signal, raw); if (signal) vmbus_setevent(channel); -- cgit v1.1