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Commit b5f53dde authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Greg Kroah-Hartman
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Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read() 



hv_ringbuffer_peek() does the same as hv_ringbuffer_read() without
advancing the read index. The only functional change this patch brings
is moving hv_need_to_signal_on_read() call under the ring_lock but this
function is just a couple of comparisons.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 45870a44

drivers/hv/ring_buffer.c

+25 −43
Original line number Diff line number Diff line
@@ -380,47 +380,9 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, 
	return 0;

}





/* Read without advancing the read index. */

int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info,

		   void *Buffer, u32 buflen)

{

	u32 bytes_avail_towrite;

	u32 bytes_avail_toread;

	u32 next_read_location = 0;

	unsigned long flags;



	spin_lock_irqsave(&Inring_info->ring_lock, flags);



	hv_get_ringbuffer_availbytes(Inring_info,

				&bytes_avail_toread,

				&bytes_avail_towrite);



	/* Make sure there is something to read */

	if (bytes_avail_toread < buflen) {



		spin_unlock_irqrestore(&Inring_info->ring_lock, flags);



		return -EAGAIN;

	}



	/* Convert to byte offset */

	next_read_location = hv_get_next_read_location(Inring_info);



	next_read_location = hv_copyfrom_ringbuffer(Inring_info,

						Buffer,

						buflen,

						next_read_location);



	spin_unlock_irqrestore(&Inring_info->ring_lock, flags);



	return 0;

}





/* Read and advance the read index. */

int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,

		   u32 buflen, u32 offset, bool *signal)

static inline int __hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,

				       void *buffer, u32 buflen, u32 offset,

				       bool *signal, bool advance)

{

	u32 bytes_avail_towrite;

	u32 bytes_avail_toread;
@@ -452,6 +414,9 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, 
						buflen,

						next_read_location);



	if (!advance)

		goto out_unlock;



	next_read_location = hv_copyfrom_ringbuffer(inring_info,

						&prev_indices,

						sizeof(u64),
@@ -467,9 +432,26 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, 
	/* Update the read index */

	hv_set_next_read_location(inring_info, next_read_location);



	spin_unlock_irqrestore(&inring_info->ring_lock, flags);



	*signal = hv_need_to_signal_on_read(bytes_avail_towrite, inring_info);



out_unlock:

	spin_unlock_irqrestore(&inring_info->ring_lock, flags);

	return 0;

}



/* Read from ring buffer without advancing the read index. */

int hv_ringbuffer_peek(struct hv_ring_buffer_info *inring_info,

		       void *buffer, u32 buflen)

{

	return __hv_ringbuffer_read(inring_info, buffer, buflen,

				    0, NULL, false);

}



/* Read from ring buffer and advance the read index. */

int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,

		       void *buffer, u32 buflen, u32 offset,

		       bool *signal)

{

	return __hv_ringbuffer_read(inring_info, buffer, buflen,

				    offset, signal, true);

}