1 files changed, 556 insertions, 0 deletions

diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c
new file mode 100644
index 000000000000..1f8acc9f9a88
--- /dev/null
+++ b/fs/orangefs/orangefs-bufmap.c
@@ -0,0 +1,556 @@
+/*
+ * (C) 2001 Clemson University and The University of Chicago
+ *
+ * See COPYING in top-level directory.
+ */
+#include "protocol.h"
+#include "orangefs-kernel.h"
+#include "orangefs-bufmap.h"
+
+struct slot_map {
+        int c;
+        wait_queue_head_t q;
+        int count;
+        unsigned long *map;
+};
+
+static struct slot_map rw_map = {
+        .c = -1,
+        .q = __WAIT_QUEUE_HEAD_INITIALIZER(rw_map.q)
+};
+static struct slot_map readdir_map = {
+        .c = -1,
+        .q = __WAIT_QUEUE_HEAD_INITIALIZER(readdir_map.q)
+};
+
+
+static void install(struct slot_map *m, int count, unsigned long *map)
+{
+        spin_lock(&m->q.lock);
+        m->c = m->count = count;
+        m->map = map;
+        wake_up_all_locked(&m->q);
+        spin_unlock(&m->q.lock);
+}
+
+static void mark_killed(struct slot_map *m)
+{
+        spin_lock(&m->q.lock);
+        m->c -= m->count + 1;
+        spin_unlock(&m->q.lock);
+}
+
+static void run_down(struct slot_map *m)
+{
+        DEFINE_WAIT(wait);
+        spin_lock(&m->q.lock);
+        if (m->c != -1) {
+                for (;;) {
+                        if (likely(list_empty(&wait.task_list)))
+                                __add_wait_queue_tail(&m->q, &wait);
+                        set_current_state(TASK_UNINTERRUPTIBLE);
+
+                        if (m->c == -1)
+                                break;
+
+                        spin_unlock(&m->q.lock);
+                        schedule();
+                        spin_lock(&m->q.lock);
+                }
+                __remove_wait_queue(&m->q, &wait);
+                __set_current_state(TASK_RUNNING);
+        }
+        m->map = NULL;
+        spin_unlock(&m->q.lock);
+}
+
+static void put(struct slot_map *m, int slot)
+{
+        int v;
+        spin_lock(&m->q.lock);
+        __clear_bit(slot, m->map);
+        v = ++m->c;
+        if (unlikely(v == 1))   /* no free slots -> one free slot */
+                wake_up_locked(&m->q);
+        else if (unlikely(v == -1))     /* finished dying */
+                wake_up_all_locked(&m->q);
+        spin_unlock(&m->q.lock);
+}
+
+static int wait_for_free(struct slot_map *m)
+{
+        long left = slot_timeout_secs * HZ;
+        DEFINE_WAIT(wait);
+
+        do {
+                long n = left, t;
+                if (likely(list_empty(&wait.task_list)))
+                        __add_wait_queue_tail_exclusive(&m->q, &wait);
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                if (m->c > 0)
+                        break;
+
+                if (m->c < 0) {
+                        /* we are waiting for map to be installed */
+                        /* it would better be there soon, or we go away */
+                        if (n > ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ)
+                                n = ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ;
+                }
+                spin_unlock(&m->q.lock);
+                t = schedule_timeout(n);
+                spin_lock(&m->q.lock);
+                if (unlikely(!t) && n != left && m->c < 0)
+                        left = t;
+                else
+                        left = t + (left - n);
+                if (unlikely(signal_pending(current)))
+                        left = -EINTR;
+        } while (left > 0);
+
+        if (!list_empty(&wait.task_list))
+                list_del(&wait.task_list);
+        else if (left <= 0 && waitqueue_active(&m->q))
+                __wake_up_locked_key(&m->q, TASK_INTERRUPTIBLE, NULL);
+        __set_current_state(TASK_RUNNING);
+
+        if (likely(left > 0))
+                return 0;
+
+        return left < 0 ? -EINTR : -ETIMEDOUT;
+}
+
+static int get(struct slot_map *m)
+{
+        int res = 0;
+        spin_lock(&m->q.lock);
+        if (unlikely(m->c <= 0))
+                res = wait_for_free(m);
+        if (likely(!res)) {
+                m->c--;
+                res = find_first_zero_bit(m->map, m->count);
+                __set_bit(res, m->map);
+        }
+        spin_unlock(&m->q.lock);
+        return res;
+}
+
+/* used to describe mapped buffers */
+struct orangefs_bufmap_desc {
+        void *uaddr;                    /* user space address pointer */
+        struct page **page_array;       /* array of mapped pages */
+        int array_count;                /* size of above arrays */
+        struct list_head list_link;
+};
+
+static struct orangefs_bufmap {
+        int desc_size;
+        int desc_shift;
+        int desc_count;
+        int total_size;
+        int page_count;
+
+        struct page **page_array;
+        struct orangefs_bufmap_desc *desc_array;
+
+        /* array to track usage of buffer descriptors */
+        unsigned long *buffer_index_array;
+
+        /* array to track usage of buffer descriptors for readdir */
+#define N DIV_ROUND_UP(ORANGEFS_READDIR_DEFAULT_DESC_COUNT, BITS_PER_LONG)
+        unsigned long readdir_index_array[N];
+#undef N
+} *__orangefs_bufmap;
+
+static DEFINE_SPINLOCK(orangefs_bufmap_lock);
+
+static void
+orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
+{
+        int i;
+
+        for (i = 0; i < bufmap->page_count; i++)
+                page_cache_release(bufmap->page_array[i]);
+}
+
+static void
+orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
+{
+        kfree(bufmap->page_array);
+        kfree(bufmap->desc_array);
+        kfree(bufmap->buffer_index_array);
+        kfree(bufmap);
+}
+
+/*
+ * XXX: Can the size and shift change while the caller gives up the 
+ * XXX: lock between calling this and doing something useful?
+ */
+
+int orangefs_bufmap_size_query(void)
+{
+        struct orangefs_bufmap *bufmap;
+        int size = 0;
+        spin_lock(&orangefs_bufmap_lock);
+        bufmap = __orangefs_bufmap;
+        if (bufmap)
+                size = bufmap->desc_size;
+        spin_unlock(&orangefs_bufmap_lock);
+        return size;
+}
+
+int orangefs_bufmap_shift_query(void)
+{
+        struct orangefs_bufmap *bufmap;
+        int shift = 0;
+        spin_lock(&orangefs_bufmap_lock);
+        bufmap = __orangefs_bufmap;
+        if (bufmap)
+                shift = bufmap->desc_shift;
+        spin_unlock(&orangefs_bufmap_lock);
+        return shift;
+}
+
+static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
+static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
+
+/*
+ * orangefs_get_bufmap_init
+ *
+ * If bufmap_init is 1, then the shared memory system, including the
+ * buffer_index_array, is available.  Otherwise, it is not.
+ *
+ * returns the value of bufmap_init
+ */
+int orangefs_get_bufmap_init(void)
+{
+        return __orangefs_bufmap ? 1 : 0;
+}
+
+
+static struct orangefs_bufmap *
+orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
+{
+        struct orangefs_bufmap *bufmap;
+
+        bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
+        if (!bufmap)
+                goto out;
+
+        bufmap->total_size = user_desc->total_size;
+        bufmap->desc_count = user_desc->count;
+        bufmap->desc_size = user_desc->size;
+        bufmap->desc_shift = ilog2(bufmap->desc_size);
+
+        bufmap->buffer_index_array =
+                kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
+        if (!bufmap->buffer_index_array) {
+                gossip_err("orangefs: could not allocate %d buffer indices\n",
+                                bufmap->desc_count);
+                goto out_free_bufmap;
+        }
+
+        bufmap->desc_array =
+                kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
+                        GFP_KERNEL);
+        if (!bufmap->desc_array) {
+                gossip_err("orangefs: could not allocate %d descriptors\n",
+                                bufmap->desc_count);
+                goto out_free_index_array;
+        }
+
+        bufmap->page_count = bufmap->total_size / PAGE_SIZE;
+
+        /* allocate storage to track our page mappings */
+        bufmap->page_array =
+                kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
+        if (!bufmap->page_array)
+                goto out_free_desc_array;
+
+        return bufmap;
+
+out_free_desc_array:
+        kfree(bufmap->desc_array);
+out_free_index_array:
+        kfree(bufmap->buffer_index_array);
+out_free_bufmap:
+        kfree(bufmap);
+out:
+        return NULL;
+}
+
+static int
+orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
+                struct ORANGEFS_dev_map_desc *user_desc)
+{
+        int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
+        int offset = 0, ret, i;
+
+        /* map the pages */
+        ret = get_user_pages_fast((unsigned long)user_desc->ptr,
+                             bufmap->page_count, 1, bufmap->page_array);
+
+        if (ret < 0)
+                return ret;
+
+        if (ret != bufmap->page_count) {
+                gossip_err("orangefs error: asked for %d pages, only got %d.\n",
+                                bufmap->page_count, ret);
+
+                for (i = 0; i < ret; i++) {
+                        SetPageError(bufmap->page_array[i]);
+                        page_cache_release(bufmap->page_array[i]);
+                }
+                return -ENOMEM;
+        }
+
+        /*
+         * ideally we want to get kernel space pointers for each page, but
+         * we can't kmap that many pages at once if highmem is being used.
+         * so instead, we just kmap/kunmap the page address each time the
+         * kaddr is needed.
+         */
+        for (i = 0; i < bufmap->page_count; i++)
+                flush_dcache_page(bufmap->page_array[i]);
+
+        /* build a list of available descriptors */
+        for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
+                bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
+                bufmap->desc_array[i].array_count = pages_per_desc;
+                bufmap->desc_array[i].uaddr =
+                    (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
+                offset += pages_per_desc;
+        }
+
+        return 0;
+}
+
+/*
+ * orangefs_bufmap_initialize()
+ *
+ * initializes the mapped buffer interface
+ *
+ * returns 0 on success, -errno on failure
+ */
+int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
+{
+        struct orangefs_bufmap *bufmap;
+        int ret = -EINVAL;
+
+        gossip_debug(GOSSIP_BUFMAP_DEBUG,
+                     "orangefs_bufmap_initialize: called (ptr ("
+                     "%p) sz (%d) cnt(%d).\n",
+                     user_desc->ptr,
+                     user_desc->size,
+                     user_desc->count);
+
+        /*
+         * sanity check alignment and size of buffer that caller wants to
+         * work with
+         */
+        if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
+            (unsigned long)user_desc->ptr) {
+                gossip_err("orangefs error: memory alignment (front). %p\n",
+                           user_desc->ptr);
+                goto out;
+        }
+
+        if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
+            != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
+                gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
+                           user_desc->ptr,
+                           user_desc->total_size);
+                goto out;
+        }
+
+        if (user_desc->total_size != (user_desc->size * user_desc->count)) {
+                gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
+                           user_desc->total_size,
+                           user_desc->size,
+                           user_desc->count);
+                goto out;
+        }
+
+        if ((user_desc->size % PAGE_SIZE) != 0) {
+                gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
+                           user_desc->size);
+                goto out;
+        }
+
+        ret = -ENOMEM;
+        bufmap = orangefs_bufmap_alloc(user_desc);
+        if (!bufmap)
+                goto out;
+
+        ret = orangefs_bufmap_map(bufmap, user_desc);
+        if (ret)
+                goto out_free_bufmap;
+
+
+        spin_lock(&orangefs_bufmap_lock);
+        if (__orangefs_bufmap) {
+                spin_unlock(&orangefs_bufmap_lock);
+                gossip_err("orangefs: error: bufmap already initialized.\n");
+                ret = -EINVAL;
+                goto out_unmap_bufmap;
+        }
+        __orangefs_bufmap = bufmap;
+        install(&rw_map,
+                bufmap->desc_count,
+                bufmap->buffer_index_array);
+        install(&readdir_map,
+                ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
+                bufmap->readdir_index_array);
+        spin_unlock(&orangefs_bufmap_lock);
+
+        gossip_debug(GOSSIP_BUFMAP_DEBUG,
+                     "orangefs_bufmap_initialize: exiting normally\n");
+        return 0;
+
+out_unmap_bufmap:
+        orangefs_bufmap_unmap(bufmap);
+out_free_bufmap:
+        orangefs_bufmap_free(bufmap);
+out:
+        return ret;
+}
+
+/*
+ * orangefs_bufmap_finalize()
+ *
+ * shuts down the mapped buffer interface and releases any resources
+ * associated with it
+ *
+ * no return value
+ */
+void orangefs_bufmap_finalize(void)
+{
+        struct orangefs_bufmap *bufmap = __orangefs_bufmap;
+        if (!bufmap)
+                return;
+        gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
+        mark_killed(&rw_map);
+        mark_killed(&readdir_map);
+        gossip_debug(GOSSIP_BUFMAP_DEBUG,
+                     "orangefs_bufmap_finalize: exiting normally\n");
+}
+
+void orangefs_bufmap_run_down(void)
+{
+        struct orangefs_bufmap *bufmap = __orangefs_bufmap;
+        if (!bufmap)
+                return;
+        run_down(&rw_map);
+        run_down(&readdir_map);
+        spin_lock(&orangefs_bufmap_lock);
+        __orangefs_bufmap = NULL;
+        spin_unlock(&orangefs_bufmap_lock);
+        orangefs_bufmap_unmap(bufmap);
+        orangefs_bufmap_free(bufmap);
+}
+
+/*
+ * orangefs_bufmap_get()
+ *
+ * gets a free mapped buffer descriptor, will sleep until one becomes
+ * available if necessary
+ *
+ * returns slot on success, -errno on failure
+ */
+int orangefs_bufmap_get(void)
+{
+        return get(&rw_map);
+}
+
+/*
+ * orangefs_bufmap_put()
+ *
+ * returns a mapped buffer descriptor to the collection
+ *
+ * no return value
+ */
+void orangefs_bufmap_put(int buffer_index)
+{
+        put(&rw_map, buffer_index);
+}
+
+/*
+ * orangefs_readdir_index_get()
+ *
+ * gets a free descriptor, will sleep until one becomes
+ * available if necessary.
+ * Although the readdir buffers are not mapped into kernel space
+ * we could do that at a later point of time. Regardless, these
+ * indices are used by the client-core.
+ *
+ * returns slot on success, -errno on failure
+ */
+int orangefs_readdir_index_get(void)
+{
+        return get(&readdir_map);
+}
+
+void orangefs_readdir_index_put(int buffer_index)
+{
+        put(&readdir_map, buffer_index);
+}
+
+/*
+ * we've been handed an iovec, we need to copy it to 
+ * the shared memory descriptor at "buffer_index".
+ */
+int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
+                                int buffer_index,
+                                size_t size)
+{
+        struct orangefs_bufmap_desc *to;
+        int i;
+
+        gossip_debug(GOSSIP_BUFMAP_DEBUG,
+                     "%s: buffer_index:%d: size:%zu:\n",
+                     __func__, buffer_index, size);
+
+        to = &__orangefs_bufmap->desc_array[buffer_index];
+        for (i = 0; size; i++) {
+                struct page *page = to->page_array[i];
+                size_t n = size;
+                if (n > PAGE_SIZE)
+                        n = PAGE_SIZE;
+                n = copy_page_from_iter(page, 0, n, iter);
+                if (!n)
+                        return -EFAULT;
+                size -= n;
+        }
+        return 0;
+
+}
+
+/*
+ * we've been handed an iovec, we need to fill it from
+ * the shared memory descriptor at "buffer_index".
+ */
+int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
+                                    int buffer_index,
+                                    size_t size)
+{
+        struct orangefs_bufmap_desc *from;
+        int i;
+
+        from = &__orangefs_bufmap->desc_array[buffer_index];
+        gossip_debug(GOSSIP_BUFMAP_DEBUG,
+                     "%s: buffer_index:%d: size:%zu:\n",
+                     __func__, buffer_index, size);
+
+
+        for (i = 0; size; i++) {
+                struct page *page = from->page_array[i];
+                size_t n = size;
+                if (n > PAGE_SIZE)
+                        n = PAGE_SIZE;
+                n = copy_page_to_iter(page, 0, n, iter);
+                if (!n)
+                        return -EFAULT;
+                size -= n;
+        }
+        return 0;
+}