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path: root/drivers/hv/ring_buffer.c
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Diffstat (limited to 'drivers/hv/ring_buffer.c')
-rw-r--r--drivers/hv/ring_buffer.c76
1 files changed, 47 insertions, 29 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index fe586bf74e17..08043da1a61c 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -27,6 +27,8 @@
#include <linux/mm.h>
#include <linux/hyperv.h>
#include <linux/uio.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
#include "hyperv_vmbus.h"
@@ -66,12 +68,20 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi)
* arrived.
*/
-static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
+static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi,
+ enum hv_signal_policy policy)
{
virt_mb();
if (READ_ONCE(rbi->ring_buffer->interrupt_mask))
return false;
+ /*
+ * When the client wants to control signaling,
+ * we only honour the host interrupt mask.
+ */
+ if (policy == HV_SIGNAL_POLICY_EXPLICIT)
+ return true;
+
/* check interrupt_mask before read_index */
virt_rmb();
/*
@@ -162,18 +172,7 @@ static u32 hv_copyfrom_ringbuffer(
void *ring_buffer = hv_get_ring_buffer(ring_info);
u32 ring_buffer_size = hv_get_ring_buffersize(ring_info);
- u32 frag_len;
-
- /* wrap-around detected at the src */
- if (destlen > ring_buffer_size - start_read_offset) {
- frag_len = ring_buffer_size - start_read_offset;
-
- memcpy(dest, ring_buffer + start_read_offset, frag_len);
- memcpy(dest + frag_len, ring_buffer, destlen - frag_len);
- } else
-
- memcpy(dest, ring_buffer + start_read_offset, destlen);
-
+ memcpy(dest, ring_buffer + start_read_offset, destlen);
start_read_offset += destlen;
start_read_offset %= ring_buffer_size;
@@ -194,15 +193,8 @@ static u32 hv_copyto_ringbuffer(
{
void *ring_buffer = hv_get_ring_buffer(ring_info);
u32 ring_buffer_size = hv_get_ring_buffersize(ring_info);
- u32 frag_len;
- /* wrap-around detected! */
- if (srclen > ring_buffer_size - start_write_offset) {
- frag_len = ring_buffer_size - start_write_offset;
- memcpy(ring_buffer + start_write_offset, src, frag_len);
- memcpy(ring_buffer, src + frag_len, srclen - frag_len);
- } else
- memcpy(ring_buffer + start_write_offset, src, srclen);
+ memcpy(ring_buffer + start_write_offset, src, srclen);
start_write_offset += srclen;
start_write_offset %= ring_buffer_size;
@@ -235,22 +227,46 @@ void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
/* Initialize the ring buffer. */
int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
- void *buffer, u32 buflen)
+ struct page *pages, u32 page_cnt)
{
- if (sizeof(struct hv_ring_buffer) != PAGE_SIZE)
- return -EINVAL;
+ int i;
+ struct page **pages_wraparound;
+
+ BUILD_BUG_ON((sizeof(struct hv_ring_buffer) != PAGE_SIZE));
memset(ring_info, 0, sizeof(struct hv_ring_buffer_info));
- ring_info->ring_buffer = (struct hv_ring_buffer *)buffer;
+ /*
+ * First page holds struct hv_ring_buffer, do wraparound mapping for
+ * the rest.
+ */
+ pages_wraparound = kzalloc(sizeof(struct page *) * (page_cnt * 2 - 1),
+ GFP_KERNEL);
+ if (!pages_wraparound)
+ return -ENOMEM;
+
+ pages_wraparound[0] = pages;
+ for (i = 0; i < 2 * (page_cnt - 1); i++)
+ pages_wraparound[i + 1] = &pages[i % (page_cnt - 1) + 1];
+
+ ring_info->ring_buffer = (struct hv_ring_buffer *)
+ vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP, PAGE_KERNEL);
+
+ kfree(pages_wraparound);
+
+
+ if (!ring_info->ring_buffer)
+ return -ENOMEM;
+
ring_info->ring_buffer->read_index =
ring_info->ring_buffer->write_index = 0;
/* Set the feature bit for enabling flow control. */
ring_info->ring_buffer->feature_bits.value = 1;
- ring_info->ring_size = buflen;
- ring_info->ring_datasize = buflen - sizeof(struct hv_ring_buffer);
+ ring_info->ring_size = page_cnt << PAGE_SHIFT;
+ ring_info->ring_datasize = ring_info->ring_size -
+ sizeof(struct hv_ring_buffer);
spin_lock_init(&ring_info->ring_lock);
@@ -260,11 +276,13 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
/* Cleanup the ring buffer. */
void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
{
+ vunmap(ring_info->ring_buffer);
}
/* Write to the ring buffer. */
int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
- struct kvec *kv_list, u32 kv_count, bool *signal, bool lock)
+ struct kvec *kv_list, u32 kv_count, bool *signal, bool lock,
+ enum hv_signal_policy policy)
{
int i = 0;
u32 bytes_avail_towrite;
@@ -326,7 +344,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
if (lock)
spin_unlock_irqrestore(&outring_info->ring_lock, flags);
- *signal = hv_need_to_signal(old_write, outring_info);
+ *signal = hv_need_to_signal(old_write, outring_info, policy);
return 0;
}