Store pointer to shared memory start in buf->parent.

nxt_port_mmap_t stored in arrays and it is unsafe to store
pointer to array element.

Shared memory structures and macros moved to separate header
file to be used by GO package.

1 files changed, 179 insertions, 0 deletions

diff --git a/src/nxt_port_memory_int.h b/src/nxt_port_memory_int.h
new file mode 100644
index 00000000..d82b6237
--- /dev/null
+++ b/src/nxt_port_memory_int.h
@@ -0,0 +1,179 @@
+
+/*
+ * Copyright (C) Max Romanov
+ * Copyright (C) NGINX, Inc.
+ */
+
+#ifndef _NXT_PORT_MEMORY_INT_H_INCLUDED_
+#define _NXT_PORT_MEMORY_INT_H_INCLUDED_
+
+
+#include <stdint.h>
+#include <nxt_atomic.h>
+
+
+#ifdef NXT_MMAP_TINY_CHUNK
+
+#define PORT_MMAP_CHUNK_SIZE    16
+#define PORT_MMAP_HEADER_SIZE   1024
+#define PORT_MMAP_DATA_SIZE     1024
+
+#else
+
+#define PORT_MMAP_CHUNK_SIZE    (1024 * 16)
+#define PORT_MMAP_HEADER_SIZE   (1024 * 4)
+#define PORT_MMAP_DATA_SIZE     (1024 * 1024 * 10)
+
+#endif
+
+
+#define PORT_MMAP_SIZE          (PORT_MMAP_HEADER_SIZE + PORT_MMAP_DATA_SIZE)
+#define PORT_MMAP_CHUNK_COUNT   (PORT_MMAP_DATA_SIZE / PORT_MMAP_CHUNK_SIZE)
+
+
+typedef uint32_t  nxt_chunk_id_t;
+
+typedef nxt_atomic_uint_t  nxt_free_map_t;
+
+#define FREE_BITS (sizeof(nxt_free_map_t) * 8)
+
+#define FREE_IDX(nchunk) ((nchunk) / FREE_BITS)
+
+#define FREE_MASK(nchunk)                                                     \
+    ( 1ULL << ( (nchunk) % FREE_BITS ) )
+
+#define MAX_FREE_IDX FREE_IDX(PORT_MMAP_CHUNK_COUNT)
+
+
+/* Mapped at the start of shared memory segment. */
+struct nxt_port_mmap_header_s {
+    uint32_t        id;
+    nxt_pid_t       pid; /* For sanity check. */
+    nxt_free_map_t  free_map[MAX_FREE_IDX];
+};
+
+
+/*
+ * Element of nxt_process_t.incoming/outgoing, shared memory segment
+ * descriptor.
+ */
+struct nxt_port_mmap_s {
+    nxt_port_mmap_header_t  *hdr;
+};
+
+typedef struct nxt_port_mmap_msg_s nxt_port_mmap_msg_t;
+
+/* Passed as a second iov chunk when 'mmap' bit in nxt_port_msg_t is 1. */
+struct nxt_port_mmap_msg_s {
+    uint32_t            mmap_id;    /* Mmap index in nxt_process_t.outgoing. */
+    nxt_chunk_id_t      chunk_id;   /* Mmap chunk index. */
+    uint32_t            size;       /* Payload data size. */
+};
+
+
+static nxt_bool_t
+nxt_port_mmap_get_free_chunk(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t *c);
+
+#define nxt_port_mmap_get_chunk_busy(hdr, c)                                  \
+    ((hdr->free_map[FREE_IDX(c)] & FREE_MASK(c)) == 0)
+
+nxt_inline void
+nxt_port_mmap_set_chunk_busy(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c);
+
+nxt_inline nxt_bool_t
+nxt_port_mmap_chk_set_chunk_busy(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c);
+
+nxt_inline void
+nxt_port_mmap_set_chunk_free(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c);
+
+nxt_inline nxt_chunk_id_t
+nxt_port_mmap_chunk_id(nxt_port_mmap_header_t *hdr, u_char *p)
+{
+    u_char  *mm_start;
+
+    mm_start = (u_char *) hdr;
+
+    return ((p - mm_start) - PORT_MMAP_HEADER_SIZE) / PORT_MMAP_CHUNK_SIZE;
+}
+
+
+nxt_inline u_char *
+nxt_port_mmap_chunk_start(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c)
+{
+    u_char  *mm_start;
+
+    mm_start = (u_char *) hdr;
+
+    return mm_start + PORT_MMAP_HEADER_SIZE + c * PORT_MMAP_CHUNK_SIZE;
+}
+
+
+static nxt_bool_t
+nxt_port_mmap_get_free_chunk(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t *c)
+{
+    int             ffs;
+    size_t          i;
+    nxt_chunk_id_t  chunk;
+    nxt_free_map_t  bits;
+    nxt_free_map_t  *free_map;
+
+    free_map = hdr->free_map;
+
+    for (i = 0; i < MAX_FREE_IDX; i++) {
+        bits = free_map[i];
+        if (bits == 0) {
+            continue;
+        }
+
+        ffs = __builtin_ffsll(bits);
+        if (ffs != 0) {
+            chunk = i * FREE_BITS + ffs - 1;
+
+            if (nxt_port_mmap_chk_set_chunk_busy(hdr, chunk)) {
+                *c = chunk;
+                return 1;
+            }
+        }
+    }
+
+    return 0;
+}
+
+
+nxt_inline void
+nxt_port_mmap_set_chunk_busy(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c)
+{
+    nxt_atomic_and_fetch(hdr->free_map + FREE_IDX(c), ~FREE_MASK(c));
+}
+
+
+nxt_inline nxt_bool_t
+nxt_port_mmap_chk_set_chunk_busy(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c)
+{
+    nxt_free_map_t  *f;
+    nxt_free_map_t  free_val, busy_val;
+
+    f = hdr->free_map + FREE_IDX(c);
+
+    while ( (*f & FREE_MASK(c)) != 0 ) {
+
+        free_val = *f | FREE_MASK(c);
+        busy_val = free_val & ~FREE_MASK(c);
+
+        if (nxt_atomic_cmp_set(f, free_val, busy_val) != 0) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+
+nxt_inline void
+nxt_port_mmap_set_chunk_free(nxt_port_mmap_header_t *hdr, nxt_chunk_id_t c)
+{
+    nxt_atomic_or_fetch(hdr->free_map + FREE_IDX(c), FREE_MASK(c));
+}
+
+
+#endif /* _NXT_PORT_MEMORY_INT_H_INCLUDED_ */