diff options
| author | Long Li <longli@microsoft.com> | 2018-03-28 03:48:38 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2018-04-19 02:32:51 +0300 |
| commit | 63273cb40101b6f303a5493f1bdf629d4ab3746b (patch) | |
| tree | 34076c5b51b7acf623d5275e3aa96e726aadf5ad | |
| parent | b6240a4df0186c03e5ffff6f61570ed31a1a5172 (diff) | |
| download | linux-63273cb40101b6f303a5493f1bdf629d4ab3746b.tar.xz | |
scsi: vmbus: Add function to report available ring buffer to write in total ring size percentage
Netvsc has a function to calculate how much ring buffer in percentage is
available to write. This function is also useful for storvsc and other
vmbus devices.
Define a similar function in vmbus to be used by other vmbus devices.
Signed-off-by: Long Li <longli@microsoft.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/hv/ring_buffer.c | 2 | ||||
| -rw-r--r-- | include/linux/hyperv.h | 12 |
2 files changed, 14 insertions, 0 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 8699bb969e7e..3c836c099a8f 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -227,6 +227,8 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, ring_info->ring_buffer->feature_bits.value = 1; ring_info->ring_size = page_cnt << PAGE_SHIFT; + ring_info->ring_size_div10_reciprocal = + reciprocal_value(ring_info->ring_size / 10); ring_info->ring_datasize = ring_info->ring_size - sizeof(struct hv_ring_buffer); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 192ed8fbc403..9ac954ee577e 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -35,6 +35,7 @@ #include <linux/device.h> #include <linux/mod_devicetable.h> #include <linux/interrupt.h> +#include <linux/reciprocal_div.h> #define MAX_PAGE_BUFFER_COUNT 32 #define MAX_MULTIPAGE_BUFFER_COUNT 32 /* 128K */ @@ -120,6 +121,7 @@ struct hv_ring_buffer { struct hv_ring_buffer_info { struct hv_ring_buffer *ring_buffer; u32 ring_size; /* Include the shared header */ + struct reciprocal_value ring_size_div10_reciprocal; spinlock_t ring_lock; u32 ring_datasize; /* < ring_size */ @@ -154,6 +156,16 @@ static inline u32 hv_get_bytes_to_write(const struct hv_ring_buffer_info *rbi) return write; } +static inline u32 hv_get_avail_to_write_percent( + const struct hv_ring_buffer_info *rbi) +{ + u32 avail_write = hv_get_bytes_to_write(rbi); + + return reciprocal_divide( + (avail_write << 3) + (avail_write << 1), + rbi->ring_size_div10_reciprocal); +} + /* * VMBUS version is 32 bit entity broken up into * two 16 bit quantities: major_number. minor_number. |