X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=lib%2Fringbuffer%2Fbackend.h;h=b362a04a436bfe64c640f694968032fb7de5aa32;hb=8ec496cfb24b29a54c057a332fc91e761994999e;hp=c0142071666bed5df347b3ab96d3762e9830ddf9;hpb=5671a6610b06175832338ed78db486b59bc5246c;p=lttng-modules.git

diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h
index c0142071..b362a04a 100644
--- a/lib/ringbuffer/backend.h
+++ b/lib/ringbuffer/backend.h
@@ -83,7 +83,7 @@ lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
  * backend-specific memcpy() operation. Calls the slow path (_ring_buffer_write)
  * if copy is crossing a page boundary.
  */
-static inline
+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)
@@ -168,7 +168,7 @@ void lib_ring_buffer_memset(const struct lib_ring_buffer_config *config,
  * terminating character is found in @src. Returns the number of bytes
  * copied. Does *not* terminate @dest with NULL terminating character.
  */
-static inline
+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)
 {
@@ -199,7 +199,7 @@ size_t lib_ring_buffer_do_strcpy(const struct lib_ring_buffer_config *config,
  * directly without having the src pointer checked with access_ok()
  * previously.
  */
-static inline
+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)
 {
@@ -297,7 +297,7 @@ void lib_ring_buffer_strcpy(const struct lib_ring_buffer_config *config,
  * (_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
+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)
@@ -334,8 +334,7 @@ void lib_ring_buffer_copy_from_user_inatomic(const struct lib_ring_buffer_config
 			rpages->p[index].virt + (offset & ~PAGE_MASK),
 			src, len);
 		if (unlikely(ret > 0)) {
-			len -= (pagecpy - ret);
-			offset += (pagecpy - ret);
+			/* Copy failed. */
 			goto fill_buffer;
 		}
 	} else {
@@ -479,4 +478,29 @@ unsigned long lib_ring_buffer_get_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 (!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 */