Rewrite the kernel hashtable struct

kernel/hshtb.h

@@ -4,47 +4,81 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include "hal/hal.h"
+#include "util/util.h"
 
-#define HSHTB_FNV32_BASE 0x811c9dc5
+#define HSHTB_FNV32_OFF 0x811c9dc5u
+#define HSHTB_FNV32_PRIME 0x01000193u
 
-static inline uint32_t hshtb_fnv32(char *s, size_t len) {
+static inline uint32_t hshtb_fnv32(const void *data, size_t len) {
-  uint32_t h = HSHTB_FNV32_BASE;
+  const unsigned char *p = (const unsigned char *)data;
+  uint32_t h = HSHTB_FNV32_OFF;
   for (size_t i = 0; i < len; i++) {
-    h ^= s[i];
+    h ^= p[i];
-    h += (h << 1) + (h << 4) + (h << 7) + (h << 8) + (h << 24);
+    h *= HSHTB_FNV32_PRIME;
   }
-  return h >> 8;
+  return h;
 }
 
-#define HSHTB_ALLOC(tb, name, k, keyname, out) \
+enum {
+  HSHTB_EMPTY = 0,
+  HSHTB_TAKEN = 1,
+  HSHTB_TOMB = 2,
+};
+
+#define HSHTB_ALLOC(tb, keyfield, k, out) \
   do { \
-    size_t len = sizeof((tb)->name) / sizeof((tb)->name[0]); \
+    size_t __len = sizeof((tb)) / sizeof((tb)[0]); \
-    size_t idx = hshtb_fnv32(k, hal_strlen(k)) % len; \
+    uint32_t __h = hshtb_fnv32((k), strlen((k))); \
-    size_t i = idx; \
+    size_t __idx = __h % __len; \
+    size_t __start = __idx; \
+    typeof(&(tb)[0]) __tomb = NULL; \
     do { \
-      if (!(tb)->name[i].taken) { \
+      if ((tb)[__idx]._hshtbstate == HSHTB_EMPTY) { \
-        (out) = &((tb)->name[i]); \
+        typeof(&(tb)[0]) __slot = __tomb ? __tomb : &(tb)[__idx]; \
-        hal_memset((out), 0, sizeof(*(out))); \
+        hal_memset(__slot, 0, sizeof(*__slot)); \
-        (out)->taken = true; \
+        __slot->_hshtbstate = HSHTB_TAKEN; \
-        hal_memcpy((out)->keyname, k, hal_strlen(k)); \
+        hal_memcpy(__slot->keyfield, (k), MIN(sizeof(__slot->keyfield) - 1, hal_strlen((k)))); \
+        (out) = __slot; \
         break; \
       } \
-      i = (i + 1) % len; \
+      if ((tb)[__idx]._hshtbstate == HSHTB_TAKEN && hal_strcmp((tb)[__idx].keyfield, (k)) == 0) { \
-    } while(i != idx); \
+        (out) = &(tb)[__idx]; \
+        break; \
+      } \
+      if ((tb)[__idx]._hshtbstate == HSHTB_TOMB && !__tomb) { \
+        __tomb = &(tb)[__idx]; \
+      } \
+      __idx = (__idx + 1) % __len; \
+    } while(__idx != __start); \
   } while(0)
 
-#define HSHTB_GET(tb, name, k, keyname, out) \
+#define HSHTB_GET(tb, keyfield, k, out) \
   do { \
-    size_t len = sizeof((tb)->name) / sizeof((tb)->name[0]); \
+    size_t __len = sizeof((tb)) / sizeof((tb)[0]); \
-    size_t idx = hshtb_fnv32(k, hal_strlen(k)) % len; \
+    uint32_t __h = hshtb_fnv32((k), hal_strlen((k))); \
-    size_t i = idx; \
+    size_t __idx = __h % __len; \
+    size_t __start = __idx; \
+    (out) = NULL; \
     do { \
-      if (hal_memcmp((tb)->name[i].keyname, k, hal_strlen(k)) == 0) { \
+      if ((tb)[__idx]._hshtbstate == HSHTB_EMPTY) { \
-        (out) = &((tb)->name[i]); \
         break; \
       } \
-      i = (i + 1) % len; \
+      if ((tb)[__idx]._hshtbstate == HSHTB_TAKEN && hal_strcmp((tb)[__idx].keyfield, (k)) == 0) { \
-    } while(i != idx); \
+        (out) = &(tb)[__idx]; \
+        break; \
+      } \
+      __idx = (__idx + 1) % __len; \
+    } while(__idx != __start); \
+  } while(0)
+
+#define HSHTB_DELETE(tb, keyfield, k) \
+  do { \
+    typeof(&(tb)[0]) __e; \
+    HSHTB_GET((tb), (keyfield), (k), __e); \
+    if (__e) { \
+      __e->state = HSHTB_TOMB; \
+    } \
   } while(0)
 
 #endif // HSHTB_H_

kernel/vfs/vfs.c

@@ -54,7 +54,7 @@ int32_t vfs_stat(char *mountpoint, const char *path, IoctlStat *stat) {
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
-  HSHTB_GET(&VFS_TABLE, mountpoints, mountpoint, label, mp);
+  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
   spinlock_release(&VFS_TABLE.spinlock);
 
   if (mp == NULL) {
@@ -68,7 +68,7 @@ int32_t vfs_fetchdirent(char *mountpoint, const char *path, IoctlDirent *direntb
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
-  HSHTB_GET(&VFS_TABLE, mountpoints, mountpoint, label, mp);
+  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
   spinlock_release(&VFS_TABLE.spinlock);
 
   if (mp == NULL) {
@@ -82,7 +82,7 @@ int32_t vfs_mount(char *mountpoint, int32_t fstype, StoreDev *backingsd, bool fo
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
-  HSHTB_ALLOC(&VFS_TABLE, mountpoints, mountpoint, label, mp);
+  HSHTB_ALLOC(VFS_TABLE.mountpoints, label, mountpoint, mp);
   spinlock_release(&VFS_TABLE.spinlock);
 
   if (mp == NULL) {
@@ -107,7 +107,7 @@ int32_t vfs_unmount(char *mountpoint) {
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
-  HSHTB_GET(&VFS_TABLE, mountpoints, mountpoint, label, mp);
+  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
   spinlock_release(&VFS_TABLE.spinlock);
 
   if (mp == NULL) {
@@ -129,7 +129,7 @@ VfsObj *vfs_open(char *mountpoint, const char *path, uint32_t flags) {
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
-  HSHTB_GET(&VFS_TABLE, mountpoints, mountpoint, label, mp);
+  HSHTB_GET(VFS_TABLE.mountpoints, label, mountpoint, mp);
   spinlock_release(&VFS_TABLE.spinlock);
 
   if (mp == NULL) {
@@ -168,7 +168,7 @@ void vfs_init(void) {
   LOG("vfs", "init\n");
 
   for (size_t i = 0; i < LEN(VFS_TABLE.mountpoints); i++) {
-    if (!VFS_TABLE.mountpoints[i].taken) continue;
+    if (VFS_TABLE.mountpoints[i]._hshtbstate != HSHTB_TAKEN) continue;
     VfsMountPoint *vmp = &VFS_TABLE.mountpoints[i];
     LOG("vfs", "mount point %s: %s, backing device: %s\n",
         vmp->label, vfs_strings[vmp->fstype], storedev_strings[vmp->backingsd->sdtype]);

kernel/vfs/vfs.h

@@ -42,8 +42,9 @@ typedef struct VfsObj {
 } VfsObj;
 
 typedef struct VfsMountPoint {
-  bool taken;
+  int _hshtbstate;
-  uint8_t label[VFS_MOUNTPOINT_LABEL_MAX];
+  char label[VFS_MOUNTPOINT_LABEL_MAX];
+
   int32_t fstype;
   StoreDev *backingsd;