VMCI: Remove non-blocking/pinned queuepair support

We added this for a special case that doesn't exist on Linux.  Remove
the non-blocking/pinned queuepair code and simplify the driver in
preparation for adding virtual IOMMU support.

Acked-by: Aditya Sarwade <asarwade@vmware.com>
Signed-off-by: Andy King <acking@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 22 insertions, 145 deletions

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index 8ff2e5ee8fb8..8698e0c5bdb4 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -148,12 +148,10 @@ typedef int vmci_memcpy_from_queue_func(void *dest, size_t dest_offset,
 struct vmci_queue_kern_if {
         struct page **page;
         struct page **header_page;
-        void *va;
         struct mutex __mutex;   /* Protects the queue. */
         struct mutex *mutex;    /* Shared by producer and consumer queues. */
         bool host;
         size_t num_pages;
-        bool mapped;
 };
 
 /*
@@ -267,11 +265,6 @@ static void qp_free_queue(void *q, u64 size)
         if (queue) {
                 u64 i = DIV_ROUND_UP(size, PAGE_SIZE);
 
-                if (queue->kernel_if->mapped) {
-                        vunmap(queue->kernel_if->va);
-                        queue->kernel_if->va = NULL;
-                }
-
                 while (i)
                         __free_page(queue->kernel_if->page[--i]);
 
@@ -311,8 +304,6 @@ static void *qp_alloc_queue(u64 size, u32 flags)
         queue->kernel_if->header_page = NULL;   /* Unused in guest. */
         queue->kernel_if->page = (struct page **)(queue->kernel_if + 1);
         queue->kernel_if->host = false;
-        queue->kernel_if->va = NULL;
-        queue->kernel_if->mapped = false;
 
         for (i = 0; i < num_data_pages; i++) {
                 queue->kernel_if->page[i] = alloc_pages(GFP_KERNEL, 0);
@@ -320,16 +311,6 @@ static void *qp_alloc_queue(u64 size, u32 flags)
                         goto fail;
         }
 
-        if (vmci_qp_pinned(flags)) {
-                queue->kernel_if->va =
-                    vmap(queue->kernel_if->page, num_data_pages, VM_MAP,
-                         PAGE_KERNEL);
-                if (!queue->kernel_if->va)
-                        goto fail;
-
-                queue->kernel_if->mapped = true;
-        }
-
         return (void *)queue;
 
  fail:
@@ -359,11 +340,7 @@ static int __qp_memcpy_to_queue(struct vmci_queue *queue,
                 void *va;
                 size_t to_copy;
 
-                if (!kernel_if->mapped)
-                        va = kmap(kernel_if->page[page_index]);
-                else
-                        va = (void *)((u8 *)kernel_if->va +
-                                      (page_index * PAGE_SIZE));
+                va = kmap(kernel_if->page[page_index]);
 
                 if (size - bytes_copied > PAGE_SIZE - page_offset)
                         /* Enough payload to fill up from this page. */
@@ -388,8 +365,7 @@ static int __qp_memcpy_to_queue(struct vmci_queue *queue,
                 }
 
                 bytes_copied += to_copy;
-                if (!kernel_if->mapped)
-                        kunmap(kernel_if->page[page_index]);
+                kunmap(kernel_if->page[page_index]);
         }
 
         return VMCI_SUCCESS;
@@ -417,11 +393,7 @@ static int __qp_memcpy_from_queue(void *dest,
                 void *va;
                 size_t to_copy;
 
-                if (!kernel_if->mapped)
-                        va = kmap(kernel_if->page[page_index]);
-                else
-                        va = (void *)((u8 *)kernel_if->va +
-                                      (page_index * PAGE_SIZE));
+                va = kmap(kernel_if->page[page_index]);
 
                 if (size - bytes_copied > PAGE_SIZE - page_offset)
                         /* Enough payload to fill up this page. */
@@ -446,8 +418,7 @@ static int __qp_memcpy_from_queue(void *dest,
                 }
 
                 bytes_copied += to_copy;
-                if (!kernel_if->mapped)
-                        kunmap(kernel_if->page[page_index]);
+                kunmap(kernel_if->page[page_index]);
         }
 
         return VMCI_SUCCESS;
@@ -634,8 +605,6 @@ static struct vmci_queue *qp_host_alloc_queue(u64 size)
                 queue->kernel_if->header_page =
                     (struct page **)((u8 *)queue + queue_size);
                 queue->kernel_if->page = &queue->kernel_if->header_page[1];
-                queue->kernel_if->va = NULL;
-                queue->kernel_if->mapped = false;
         }
 
         return queue;
@@ -1720,21 +1689,6 @@ static int qp_broker_attach(struct qp_broker_entry *entry,
                         if (result < VMCI_SUCCESS)
                                 return result;
 
-                        /*
-                         * Preemptively load in the headers if non-blocking to
-                         * prevent blocking later.
-                         */
-                        if (entry->qp.flags & VMCI_QPFLAG_NONBLOCK) {
-                                result = qp_host_map_queues(entry->produce_q,
-                                                            entry->consume_q);
-                                if (result < VMCI_SUCCESS) {
-                                        qp_host_unregister_user_memory(
-                                                entry->produce_q,
-                                                entry->consume_q);
-                                        return result;
-                                }
-                        }
-
                         entry->state = VMCIQPB_ATTACHED_MEM;
                 } else {
                         entry->state = VMCIQPB_ATTACHED_NO_MEM;
@@ -1749,24 +1703,6 @@ static int qp_broker_attach(struct qp_broker_entry *entry,
 
                 return VMCI_ERROR_UNAVAILABLE;
         } else {
-                /*
-                 * For non-blocking queue pairs, we cannot rely on
-                 * enqueue/dequeue to map in the pages on the
-                 * host-side, since it may block, so we make an
-                 * attempt here.
-                 */
-
-                if (flags & VMCI_QPFLAG_NONBLOCK) {
-                        result =
-                            qp_host_map_queues(entry->produce_q,
-                                               entry->consume_q);
-                        if (result < VMCI_SUCCESS)
-                                return result;
-
-                        entry->qp.flags |= flags &
-                            (VMCI_QPFLAG_NONBLOCK | VMCI_QPFLAG_PINNED);
-                }
-
                 /* The host side has successfully attached to a queue pair. */
                 entry->state = VMCIQPB_ATTACHED_MEM;
         }
@@ -2543,24 +2479,19 @@ void vmci_qp_guest_endpoints_exit(void)
  * Since non-blocking isn't yet implemented on the host personality we
  * have no reason to acquire a spin lock.  So to avoid the use of an
  * unnecessary lock only acquire the mutex if we can block.
- * Note: It is assumed that QPFLAG_PINNED implies QPFLAG_NONBLOCK.  Therefore
- * we can use the same locking function for access to both the queue
- * and the queue headers as it is the same logic.  Assert this behvior.
  */
 static void qp_lock(const struct vmci_qp *qpair)
 {
-        if (vmci_can_block(qpair->flags))
-                qp_acquire_queue_mutex(qpair->produce_q);
+        qp_acquire_queue_mutex(qpair->produce_q);
 }
 
 /*
  * Helper routine that unlocks the queue pair after calling
- * qp_lock.  Respects non-blocking and pinning flags.
+ * qp_lock.
  */
 static void qp_unlock(const struct vmci_qp *qpair)
 {
-        if (vmci_can_block(qpair->flags))
-                qp_release_queue_mutex(qpair->produce_q);
+        qp_release_queue_mutex(qpair->produce_q);
 }
 
 /*
@@ -2568,17 +2499,12 @@ static void qp_unlock(const struct vmci_qp *qpair)
  * currently not mapped, it will be attempted to do so.
  */
 static int qp_map_queue_headers(struct vmci_queue *produce_q,
-                                struct vmci_queue *consume_q,
-                                bool can_block)
+                                struct vmci_queue *consume_q)
 {
         int result;
 
         if (NULL == produce_q->q_header || NULL == consume_q->q_header) {
-                if (can_block)
-                        result = qp_host_map_queues(produce_q, consume_q);
-                else
-                        result = VMCI_ERROR_QUEUEPAIR_NOT_READY;
-
+                result = qp_host_map_queues(produce_q, consume_q);
                 if (result < VMCI_SUCCESS)
                         return (produce_q->saved_header &&
                                 consume_q->saved_header) ?
@@ -2601,8 +2527,7 @@ static int qp_get_queue_headers(const struct vmci_qp *qpair,
 {
         int result;
 
-        result = qp_map_queue_headers(qpair->produce_q, qpair->consume_q,
-                                      vmci_can_block(qpair->flags));
+        result = qp_map_queue_headers(qpair->produce_q, qpair->consume_q);
         if (result == VMCI_SUCCESS) {
                 *produce_q_header = qpair->produce_q->q_header;
                 *consume_q_header = qpair->consume_q->q_header;
@@ -2645,9 +2570,6 @@ static bool qp_wait_for_ready_queue(struct vmci_qp *qpair)
 {
         unsigned int generation;
 
-        if (qpair->flags & VMCI_QPFLAG_NONBLOCK)
-                return false;
-
         qpair->blocked++;
         generation = qpair->generation;
         qp_unlock(qpair);
@@ -2674,15 +2596,14 @@ static ssize_t qp_enqueue_locked(struct vmci_queue *produce_q,
                                  const u64 produce_q_size,
                                  const void *buf,
                                  size_t buf_size,
-                                 vmci_memcpy_to_queue_func memcpy_to_queue,
-                                 bool can_block)
+                                 vmci_memcpy_to_queue_func memcpy_to_queue)
 {
         s64 free_space;
         u64 tail;
         size_t written;
         ssize_t result;
 
-        result = qp_map_queue_headers(produce_q, consume_q, can_block);
+        result = qp_map_queue_headers(produce_q, consume_q);
         if (unlikely(result != VMCI_SUCCESS))
                 return result;
 
@@ -2737,15 +2658,14 @@ static ssize_t qp_dequeue_locked(struct vmci_queue *produce_q,
                                  void *buf,
                                  size_t buf_size,
                                  vmci_memcpy_from_queue_func memcpy_from_queue,
-                                 bool update_consumer,
-                                 bool can_block)
+                                 bool update_consumer)
 {
         s64 buf_ready;
         u64 head;
         size_t read;
         ssize_t result;
 
-        result = qp_map_queue_headers(produce_q, consume_q, can_block);
+        result = qp_map_queue_headers(produce_q, consume_q);
         if (unlikely(result != VMCI_SUCCESS))
                 return result;
 
@@ -2842,32 +2762,11 @@ int vmci_qpair_alloc(struct vmci_qp **qpair,
                 route = vmci_guest_code_active() ?
                     VMCI_ROUTE_AS_GUEST : VMCI_ROUTE_AS_HOST;
 
-        /* If NONBLOCK or PINNED is set, we better be the guest personality. */
-        if ((!vmci_can_block(flags) || vmci_qp_pinned(flags)) &&
-            VMCI_ROUTE_AS_GUEST != route) {
-                pr_devel("Not guest personality w/ NONBLOCK OR PINNED set");
+        if (flags & (VMCI_QPFLAG_NONBLOCK | VMCI_QPFLAG_PINNED)) {
+                pr_devel("NONBLOCK OR PINNED set");
                 return VMCI_ERROR_INVALID_ARGS;
         }
 
-        /*
-         * Limit the size of pinned QPs and check sanity.
-         *
-         * Pinned pages implies non-blocking mode.  Mutexes aren't acquired
-         * when the NONBLOCK flag is set in qpair code; and also should not be
-         * acquired when the PINNED flagged is set.  Since pinning pages
-         * implies we want speed, it makes no sense not to have NONBLOCK
-         * set if PINNED is set.  Hence enforce this implication.
-         */
-        if (vmci_qp_pinned(flags)) {
-                if (vmci_can_block(flags)) {
-                        pr_err("Attempted to enable pinning w/o non-blocking");
-                        return VMCI_ERROR_INVALID_ARGS;
-                }
-
-                if (produce_qsize + consume_qsize > VMCI_MAX_PINNED_QP_MEMORY)
-                        return VMCI_ERROR_NO_RESOURCES;
-        }
-
         my_qpair = kzalloc(sizeof(*my_qpair), GFP_KERNEL);
         if (!my_qpair)
                 return VMCI_ERROR_NO_MEM;
@@ -3195,8 +3094,7 @@ ssize_t vmci_qpair_enqueue(struct vmci_qp *qpair,
                                            qpair->consume_q,
                                            qpair->produce_q_size,
                                            buf, buf_size,
-                                           qp_memcpy_to_queue,
-                                           vmci_can_block(qpair->flags));
+                                           qp_memcpy_to_queue);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
@@ -3237,8 +3135,7 @@ ssize_t vmci_qpair_dequeue(struct vmci_qp *qpair,
                                            qpair->consume_q,
                                            qpair->consume_q_size,
                                            buf, buf_size,
-                                           qp_memcpy_from_queue, true,
-                                           vmci_can_block(qpair->flags));
+                                           qp_memcpy_from_queue, true);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
@@ -3280,8 +3177,7 @@ ssize_t vmci_qpair_peek(struct vmci_qp *qpair,
                                            qpair->consume_q,
                                            qpair->consume_q_size,
                                            buf, buf_size,
-                                           qp_memcpy_from_queue, false,
-                                           vmci_can_block(qpair->flags));
+                                           qp_memcpy_from_queue, false);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
@@ -3323,8 +3219,7 @@ ssize_t vmci_qpair_enquev(struct vmci_qp *qpair,
                                            qpair->consume_q,
                                            qpair->produce_q_size,
                                            iov, iov_size,
-                                           qp_memcpy_to_queue_iov,
-                                           vmci_can_block(qpair->flags));
+                                           qp_memcpy_to_queue_iov);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
@@ -3367,7 +3262,7 @@ ssize_t vmci_qpair_dequev(struct vmci_qp *qpair,
                                            qpair->consume_q_size,
                                            iov, iov_size,
                                            qp_memcpy_from_queue_iov,
-                                           true, vmci_can_block(qpair->flags));
+                                           true);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
@@ -3411,7 +3306,7 @@ ssize_t vmci_qpair_peekv(struct vmci_qp *qpair,
                                            qpair->consume_q_size,
                                            iov, iov_size,
                                            qp_memcpy_from_queue_iov,
-                                           false, vmci_can_block(qpair->flags));
+                                           false);
 
                 if (result == VMCI_ERROR_QUEUEPAIR_NOT_READY &&
                     !qp_wait_for_ready_queue(qpair))
diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.h b/drivers/misc/vmw_vmci/vmci_queue_pair.h
index 58c6959f6b6d..ed177f04ef24 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.h
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.h
@@ -146,24 +146,6 @@ VMCI_QP_PAGESTORE_IS_WELLFORMED(struct vmci_qp_page_store *page_store)
         return page_store->len >= 2;
 }
 
-/*
- * Helper function to check if the non-blocking flag
- * is set for a given queue pair.
- */
-static inline bool vmci_can_block(u32 flags)
-{
-        return !(flags & VMCI_QPFLAG_NONBLOCK);
-}
-
-/*
- * Helper function to check if the queue pair is pinned
- * into memory.
- */
-static inline bool vmci_qp_pinned(u32 flags)
-{
-        return flags & VMCI_QPFLAG_PINNED;
-}
-
 void vmci_qp_broker_exit(void);
 int vmci_qp_broker_alloc(struct vmci_handle handle, u32 peer,
                          u32 flags, u32 priv_flags,