-#ifndef _LINUX_RING_BUFFER_BACKEND_H
-#define _LINUX_RING_BUFFER_BACKEND_H
+#ifndef _LIB_RING_BUFFER_BACKEND_H
+#define _LIB_RING_BUFFER_BACKEND_H
/*
- * linux/ringbuffer/backend.h
- *
- * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lib/ringbuffer/backend.h
*
* Ring buffer backend (API).
*
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Credits to Steven Rostedt for proposing to use an extra-subbuffer owned by
* the reader in flight recorder mode.
ctx->buf_offset += len;
}
+/**
+ * lib_ring_buffer_memset - write len bytes of c to a buffer backend
+ * @config : ring buffer instance configuration
+ * @bufb : ring buffer backend
+ * @offset : offset within the buffer
+ * @c : the byte to copy
+ * @len : number of bytes to copy
+ *
+ * This function writes "len" bytes of "c" to a buffer backend, at a specific
+ * offset. This is more or less a buffer backend-specific memset() operation.
+ * Calls the slow path (_ring_buffer_memset) if write is crossing a page
+ * boundary.
+ */
+static inline
+void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx, int c, size_t len)
+{
+
+ struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
+ struct channel_backend *chanb = &ctx->chan->backend;
+ size_t sbidx, index;
+ size_t offset = ctx->buf_offset;
+ ssize_t pagecpy;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+
+ offset &= chanb->buf_size - 1;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(ctx->chan,
+ config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ if (likely(pagecpy == len))
+ lib_ring_buffer_do_memset(rpages->p[index].virt
+ + (offset & ~PAGE_MASK),
+ c, len);
+ else
+ _lib_ring_buffer_memset(bufb, offset, c, len, 0);
+ ctx->buf_offset += len;
+}
+
+/**
+ * lib_ring_buffer_copy_from_user - write userspace data to a buffer backend
+ * @config : ring buffer instance configuration
+ * @ctx: ring buffer context. (input arguments only)
+ * @src : userspace source pointer to copy from
+ * @len : length of data to copy
+ *
+ * This function copies "len" bytes of data from a userspace pointer to a
+ * buffer backend, at the current context offset. This is more or less a buffer
+ * backend-specific memcpy() operation. Calls the slow path
+ * (_ring_buffer_write_from_user) if copy is crossing a page boundary.
+ */
+static inline
+void lib_ring_buffer_copy_from_user(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx,
+ const void __user *src, size_t len)
+{
+ struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
+ struct channel_backend *chanb = &ctx->chan->backend;
+ size_t sbidx, index;
+ size_t offset = ctx->buf_offset;
+ ssize_t pagecpy;
+ struct lib_ring_buffer_backend_pages *rpages;
+ unsigned long sb_bindex, id;
+ unsigned long ret;
+
+ offset &= chanb->buf_size - 1;
+ sbidx = offset >> chanb->subbuf_size_order;
+ index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
+ pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(ctx->chan,
+ config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+
+ if (unlikely(!access_ok(VERIFY_READ, src, len)))
+ goto fill_buffer;
+
+ if (likely(pagecpy == len)) {
+ ret = lib_ring_buffer_do_copy_from_user(
+ rpages->p[index].virt + (offset & ~PAGE_MASK),
+ src, len);
+ if (unlikely(ret > 0)) {
+ len -= (pagecpy - ret);
+ offset += (pagecpy - ret);
+ goto fill_buffer;
+ }
+ } else {
+ _lib_ring_buffer_copy_from_user(bufb, offset, src, len, 0);
+ }
+ ctx->buf_offset += len;
+
+ return;
+
+fill_buffer:
+ /*
+ * In the error path we call the slow path version to avoid
+ * the pollution of static inline code.
+ */
+ _lib_ring_buffer_memset(bufb, offset, 0, len, 0);
+}
+
/*
* This accessor counts the number of unread records in a buffer.
* It only provides a consistent value if no reads not writes are performed
size_t len, unsigned int flags);
loff_t lib_ring_buffer_no_llseek(struct file *file, loff_t offset, int origin);
-#endif /* _LINUX_RING_BUFFER_BACKEND_H */
+#endif /* _LIB_RING_BUFFER_BACKEND_H */
projects / lttng-modules.git / blobdiff