X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fbackend.h;fp=lib%2Fringbuffer%2Fbackend.h;h=0000000000000000000000000000000000000000;hb=2459130397d7e7eecc44a5f06a39d65c78257eef;hp=da4e92b9d89633039e5d609d964f32ce0e13dc03;hpb=5b4ea313ddc10d96388a20a42e118c758479a553;p=lttng-modules.git

diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h
deleted file mode 100644
index da4e92b9..00000000
--- a/lib/ringbuffer/backend.h
+++ /dev/null
@@ -1,463 +0,0 @@
-/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
- *
- * lib/ringbuffer/backend.h
- *
- * Ring buffer backend (API).
- *
- * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Credits to Steven Rostedt for proposing to use an extra-subbuffer owned by
- * the reader in flight recorder mode.
- */
-
-#ifndef _LIB_RING_BUFFER_BACKEND_H
-#define _LIB_RING_BUFFER_BACKEND_H
-
-#include <linux/types.h>
-#include <linux/sched.h>
-#include <linux/timer.h>
-#include <linux/wait.h>
-#include <linux/poll.h>
-#include <linux/list.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <wrapper/uaccess.h>
-
-/* Internal helpers */
-#include <wrapper/ringbuffer/backend_internal.h>
-#include <wrapper/ringbuffer/frontend_internal.h>
-
-/* Ring buffer backend API */
-
-/* Ring buffer backend access (read/write) */
-
-extern size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb,
-				   size_t offset, void *dest, size_t len);
-
-extern int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb,
-					  size_t offset, void __user *dest,
-					  size_t len);
-
-extern int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb,
-				     size_t offset, void *dest, size_t len);
-
-extern unsigned long *
-lib_ring_buffer_read_get_pfn(struct lib_ring_buffer_backend *bufb, size_t offset,
-			      void ***virt);
-
-/*
- * Return the address where a given offset is located.
- * Should be used to get the current subbuffer header pointer. Given we know
- * it's never on a page boundary, it's safe to write directly to this address,
- * as long as the write is never bigger than a page size.
- */
-extern void *
-lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
-			       size_t offset);
-extern void *
-lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
-				    size_t offset);
-
-/**
- * lib_ring_buffer_write - write data to a buffer backend
- * @config : ring buffer instance configuration
- * @ctx: ring buffer context. (input arguments only)
- * @src : source pointer to copy from
- * @len : length of data to copy
- *
- * This function copies "len" bytes of data from a source 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)
- * if copy is crossing a page boundary.
- */
-static inline __attribute__((always_inline))
-void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
-			   struct lib_ring_buffer_ctx *ctx,
-			   const void *src, size_t len)
-{
-	struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-	struct channel_backend *chanb = &ctx->chan->backend;
-	size_t index, pagecpy;
-	size_t offset = ctx->buf_offset;
-	struct lib_ring_buffer_backend_pages *backend_pages;
-
-	if (unlikely(!len))
-		return;
-	backend_pages =
-		lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
-	offset &= chanb->buf_size - 1;
-	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-	pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
-	if (likely(pagecpy == len))
-		lib_ring_buffer_do_copy(config,
-					backend_pages->p[index].virt
-					    + (offset & ~PAGE_MASK),
-					src, len);
-	else
-		_lib_ring_buffer_write(bufb, offset, src, len, 0);
-	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 index, pagecpy;
-	size_t offset = ctx->buf_offset;
-	struct lib_ring_buffer_backend_pages *backend_pages;
-
-	if (unlikely(!len))
-		return;
-	backend_pages =
-		lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
-	offset &= chanb->buf_size - 1;
-	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-	pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
-	if (likely(pagecpy == len))
-		lib_ring_buffer_do_memset(backend_pages->p[index].virt
-					  + (offset & ~PAGE_MASK),
-					  c, len);
-	else
-		_lib_ring_buffer_memset(bufb, offset, c, len, 0);
-	ctx->buf_offset += len;
-}
-
-/*
- * Copy up to @len string bytes from @src to @dest. Stop whenever a NULL
- * terminating character is found in @src. Returns the number of bytes
- * copied. Does *not* terminate @dest with NULL terminating character.
- */
-static inline __attribute__((always_inline))
-size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config,
-		char *dest, const char *src, size_t len)
-{
-	size_t count;
-
-	for (count = 0; count < len; count++) {
-		char c;
-
-		/*
-		 * Only read source character once, in case it is
-		 * modified concurrently.
-		 */
-		c = READ_ONCE(src[count]);
-		if (!c)
-			break;
-		lib_ring_buffer_do_copy(config, &dest[count], &c, 1);
-	}
-	return count;
-}
-
-/*
- * Copy up to @len string bytes from @src to @dest. Stop whenever a NULL
- * terminating character is found in @src, or when a fault occurs.
- * Returns the number of bytes copied. Does *not* terminate @dest with
- * NULL terminating character.
- *
- * This function deals with userspace pointers, it should never be called
- * directly without having the src pointer checked with access_ok()
- * previously.
- */
-static inline __attribute__((always_inline))
-size_t lib_ring_buffer_do_strcpy_from_user_inatomic(const struct lib_ring_buffer_config *config,
-		char *dest, const char __user *src, size_t len)
-{
-	size_t count;
-
-	for (count = 0; count < len; count++) {
-		int ret;
-		char c;
-
-		ret = __copy_from_user_inatomic(&c, src + count, 1);
-		if (ret || !c)
-			break;
-		lib_ring_buffer_do_copy(config, &dest[count], &c, 1);
-	}
-	return count;
-}
-
-/**
- * lib_ring_buffer_strcpy - write string data to a buffer backend
- * @config : ring buffer instance configuration
- * @ctx: ring buffer context. (input arguments only)
- * @src : source pointer to copy from
- * @len : length of data to copy
- * @pad : character to use for padding
- *
- * This function copies @len - 1 bytes of string data from a source
- * pointer to a buffer backend, followed by a terminating '\0'
- * character, at the current context offset. This is more or less a
- * buffer backend-specific strncpy() operation. If a terminating '\0'
- * character is found in @src before @len - 1 characters are copied, pad
- * the buffer with @pad characters (e.g. '#'). Calls the slow path
- * (_ring_buffer_strcpy) if copy is crossing a page boundary.
- */
-static inline
-void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config,
-			   struct lib_ring_buffer_ctx *ctx,
-			   const char *src, size_t len, int pad)
-{
-	struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-	struct channel_backend *chanb = &ctx->chan->backend;
-	size_t index, pagecpy;
-	size_t offset = ctx->buf_offset;
-	struct lib_ring_buffer_backend_pages *backend_pages;
-
-	if (unlikely(!len))
-		return;
-	backend_pages =
-		lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
-	offset &= chanb->buf_size - 1;
-	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-	pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
-	if (likely(pagecpy == len)) {
-		size_t count;
-
-		count = lib_ring_buffer_do_strcpy(config,
-					backend_pages->p[index].virt
-					    + (offset & ~PAGE_MASK),
-					src, len - 1);
-		offset += count;
-		/* Padding */
-		if (unlikely(count < len - 1)) {
-			size_t pad_len = len - 1 - count;
-
-			lib_ring_buffer_do_memset(backend_pages->p[index].virt
-						+ (offset & ~PAGE_MASK),
-					pad, pad_len);
-			offset += pad_len;
-		}
-		/* Ending '\0' */
-		lib_ring_buffer_do_memset(backend_pages->p[index].virt
-					+ (offset & ~PAGE_MASK),
-				'\0', 1);
-	} else {
-		_lib_ring_buffer_strcpy(bufb, offset, src, len, 0, pad);
-	}
-	ctx->buf_offset += len;
-}
-
-/**
- * lib_ring_buffer_copy_from_user_inatomic - 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_inatomic) if copy is crossing a page boundary.
- * Disable the page fault handler to ensure we never try to take the mmap_sem.
- */
-static inline __attribute__((always_inline))
-void lib_ring_buffer_copy_from_user_inatomic(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 index, pagecpy;
-	size_t offset = ctx->buf_offset;
-	struct lib_ring_buffer_backend_pages *backend_pages;
-	unsigned long ret;
-	mm_segment_t old_fs = get_fs();
-
-	if (unlikely(!len))
-		return;
-	backend_pages =
-		lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
-	offset &= chanb->buf_size - 1;
-	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-	pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
-
-	set_fs(KERNEL_DS);
-	pagefault_disable();
-	if (unlikely(!lttng_access_ok(VERIFY_READ, src, len)))
-		goto fill_buffer;
-
-	if (likely(pagecpy == len)) {
-		ret = lib_ring_buffer_do_copy_from_user_inatomic(
-			backend_pages->p[index].virt + (offset & ~PAGE_MASK),
-			src, len);
-		if (unlikely(ret > 0)) {
-			/* Copy failed. */
-			goto fill_buffer;
-		}
-	} else {
-		_lib_ring_buffer_copy_from_user_inatomic(bufb, offset, src, len, 0);
-	}
-	pagefault_enable();
-	set_fs(old_fs);
-	ctx->buf_offset += len;
-
-	return;
-
-fill_buffer:
-	pagefault_enable();
-	set_fs(old_fs);
-	/*
-	 * 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);
-}
-
-/**
- * lib_ring_buffer_strcpy_from_user_inatomic - write userspace string 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
- * @pad : character to use for padding
- *
- * This function copies @len - 1 bytes of string data from a userspace
- * source pointer to a buffer backend, followed by a terminating '\0'
- * character, at the current context offset. This is more or less a
- * buffer backend-specific strncpy() operation. If a terminating '\0'
- * character is found in @src before @len - 1 characters are copied, pad
- * the buffer with @pad characters (e.g. '#'). Calls the slow path
- * (_ring_buffer_strcpy_from_user_inatomic) if copy is crossing a page
- * boundary. Disable the page fault handler to ensure we never try to
- * take the mmap_sem.
- */
-static inline
-void lib_ring_buffer_strcpy_from_user_inatomic(const struct lib_ring_buffer_config *config,
-		struct lib_ring_buffer_ctx *ctx,
-		const void __user *src, size_t len, int pad)
-{
-	struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
-	struct channel_backend *chanb = &ctx->chan->backend;
-	size_t index, pagecpy;
-	size_t offset = ctx->buf_offset;
-	struct lib_ring_buffer_backend_pages *backend_pages;
-	mm_segment_t old_fs = get_fs();
-
-	if (unlikely(!len))
-		return;
-	backend_pages =
-		lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
-	offset &= chanb->buf_size - 1;
-	index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
-	pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
-
-	set_fs(KERNEL_DS);
-	pagefault_disable();
-	if (unlikely(!lttng_access_ok(VERIFY_READ, src, len)))
-		goto fill_buffer;
-
-	if (likely(pagecpy == len)) {
-		size_t count;
-
-		count = lib_ring_buffer_do_strcpy_from_user_inatomic(config,
-					backend_pages->p[index].virt
-					    + (offset & ~PAGE_MASK),
-					src, len - 1);
-		offset += count;
-		/* Padding */
-		if (unlikely(count < len - 1)) {
-			size_t pad_len = len - 1 - count;
-
-			lib_ring_buffer_do_memset(backend_pages->p[index].virt
-						+ (offset & ~PAGE_MASK),
-					pad, pad_len);
-			offset += pad_len;
-		}
-		/* Ending '\0' */
-		lib_ring_buffer_do_memset(backend_pages->p[index].virt
-					+ (offset & ~PAGE_MASK),
-				'\0', 1);
-	} else {
-		_lib_ring_buffer_strcpy_from_user_inatomic(bufb, offset, src,
-					len, 0, pad);
-	}
-	pagefault_enable();
-	set_fs(old_fs);
-	ctx->buf_offset += len;
-
-	return;
-
-fill_buffer:
-	pagefault_enable();
-	set_fs(old_fs);
-	/*
-	 * In the error path we call the slow path version to avoid
-	 * the pollution of static inline code.
-	 */
-	_lib_ring_buffer_memset(bufb, offset, pad, len - 1, 0);
-	offset += len - 1;
-	_lib_ring_buffer_memset(bufb, offset, '\0', 1, 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
- * concurrently.
- */
-static inline
-unsigned long lib_ring_buffer_get_records_unread(
-				const struct lib_ring_buffer_config *config,
-				struct lib_ring_buffer *buf)
-{
-	struct lib_ring_buffer_backend *bufb = &buf->backend;
-	struct lib_ring_buffer_backend_pages *pages;
-	unsigned long records_unread = 0, sb_bindex, id;
-	unsigned int i;
-
-	for (i = 0; i < bufb->chan->backend.num_subbuf; i++) {
-		id = bufb->buf_wsb[i].id;
-		sb_bindex = subbuffer_id_get_index(config, id);
-		pages = bufb->array[sb_bindex];
-		records_unread += v_read(config, &pages->records_unread);
-	}
-	if (config->mode == RING_BUFFER_OVERWRITE) {
-		id = bufb->buf_rsb.id;
-		sb_bindex = subbuffer_id_get_index(config, id);
-		pages = bufb->array[sb_bindex];
-		records_unread += v_read(config, &pages->records_unread);
-	}
-	return records_unread;
-}
-
-/*
- * We use __copy_from_user_inatomic to copy userspace data after
- * checking with access_ok() and disabling page faults.
- *
- * Return 0 if OK, nonzero on error.
- */
-static inline
-unsigned long lib_ring_buffer_copy_from_user_check_nofault(void *dest,
-						const void __user *src,
-						unsigned long len)
-{
-	unsigned long ret;
-	mm_segment_t old_fs;
-
-	if (!lttng_access_ok(VERIFY_READ, src, len))
-		return 1;
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	pagefault_disable();
-	ret = __copy_from_user_inatomic(dest, src, len);
-	pagefault_enable();
-	set_fs(old_fs);
-	return ret;
-}
-
-#endif /* _LIB_RING_BUFFER_BACKEND_H */