Performance: mark ring buffer do_copy callers always inline

[lttng-modules.git] / lib / ringbuffer / backend.h

diff --git a/lib/ringbuffer/backend.h b/lib/ringbuffer/backend.h
index 6f3296bc9491b2983f85ea82f2f88af2ebb6cd4c..b362a04a436bfe64c640f694968032fb7de5aa32 100644 (file)
--- a/lib/ringbuffer/backend.h
+++ b/lib/ringbuffer/backend.h
@@ -37,8 +37,8 @@
 #include <linux/uaccess.h>
 
 /* Internal helpers */
-#include "../../wrapper/ringbuffer/backend_internal.h"
-#include "../../wrapper/ringbuffer/frontend_internal.h"
+#include <wrapper/ringbuffer/backend_internal.h>
+#include <wrapper/ringbuffer/frontend_internal.h>
 
 /* Ring buffer backend API */
 
@@ -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 */