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qemu-nbd: Look up flag names in array

The existing code to convert flag bits into strings looks a bit strange
now, and if we ever add more flags, it will look even stranger.  Prevent
that from happening by making it look up the flag names in an array.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <2019040519.25740-1-mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
master
Max Reitz 2 months ago
parent
commit
c4e2aff81b
2 changed files with 43 additions and 41 deletions
  1. 26
    12
      include/block/nbd.h
  2. 17
    29
      qemu-nbd.c

+ 26
- 12
include/block/nbd.h View File

@@ -127,18 +127,32 @@ typedef struct NBDExtent {
127 127
 
128 128
 /* Transmission (export) flags: sent from server to client during handshake,
129 129
    but describe what will happen during transmission */
130
-#define NBD_FLAG_HAS_FLAGS         (1 << 0) /* Flags are there */
131
-#define NBD_FLAG_READ_ONLY         (1 << 1) /* Device is read-only */
132
-#define NBD_FLAG_SEND_FLUSH        (1 << 2) /* Send FLUSH */
133
-#define NBD_FLAG_SEND_FUA          (1 << 3) /* Send FUA (Force Unit Access) */
134
-#define NBD_FLAG_ROTATIONAL        (1 << 4) /* Use elevator algorithm -
135
-                                               rotational media */
136
-#define NBD_FLAG_SEND_TRIM         (1 << 5) /* Send TRIM (discard) */
137
-#define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* Send WRITE_ZEROES */
138
-#define NBD_FLAG_SEND_DF           (1 << 7) /* Send DF (Do not Fragment) */
139
-#define NBD_FLAG_CAN_MULTI_CONN    (1 << 8) /* Multi-client cache consistent */
140
-#define NBD_FLAG_SEND_RESIZE       (1 << 9) /* Send resize */
141
-#define NBD_FLAG_SEND_CACHE        (1 << 10) /* Send CACHE (prefetch) */
130
+enum {
131
+    NBD_FLAG_HAS_FLAGS_BIT          =  0, /* Flags are there */
132
+    NBD_FLAG_READ_ONLY_BIT          =  1, /* Device is read-only */
133
+    NBD_FLAG_SEND_FLUSH_BIT         =  2, /* Send FLUSH */
134
+    NBD_FLAG_SEND_FUA_BIT           =  3, /* Send FUA (Force Unit Access) */
135
+    NBD_FLAG_ROTATIONAL_BIT         =  4, /* Use elevator algorithm -
136
+                                             rotational media */
137
+    NBD_FLAG_SEND_TRIM_BIT          =  5, /* Send TRIM (discard) */
138
+    NBD_FLAG_SEND_WRITE_ZEROES_BIT  =  6, /* Send WRITE_ZEROES */
139
+    NBD_FLAG_SEND_DF_BIT            =  7, /* Send DF (Do not Fragment) */
140
+    NBD_FLAG_CAN_MULTI_CONN_BIT     =  8, /* Multi-client cache consistent */
141
+    NBD_FLAG_SEND_RESIZE_BIT        =  9, /* Send resize */
142
+    NBD_FLAG_SEND_CACHE_BIT         = 10, /* Send CACHE (prefetch) */
143
+};
144
+
145
+#define NBD_FLAG_HAS_FLAGS         (1 << NBD_FLAG_HAS_FLAGS_BIT)
146
+#define NBD_FLAG_READ_ONLY         (1 << NBD_FLAG_READ_ONLY_BIT)
147
+#define NBD_FLAG_SEND_FLUSH        (1 << NBD_FLAG_SEND_FLUSH_BIT)
148
+#define NBD_FLAG_SEND_FUA          (1 << NBD_FLAG_SEND_FUA_BIT)
149
+#define NBD_FLAG_ROTATIONAL        (1 << NBD_FLAG_ROTATIONAL_BIT)
150
+#define NBD_FLAG_SEND_TRIM         (1 << NBD_FLAG_SEND_TRIM_BIT)
151
+#define NBD_FLAG_SEND_WRITE_ZEROES (1 << NBD_FLAG_SEND_WRITE_ZEROES_BIT)
152
+#define NBD_FLAG_SEND_DF           (1 << NBD_FLAG_SEND_DF_BIT)
153
+#define NBD_FLAG_CAN_MULTI_CONN    (1 << NBD_FLAG_CAN_MULTI_CONN_BIT)
154
+#define NBD_FLAG_SEND_RESIZE       (1 << NBD_FLAG_SEND_RESIZE_BIT)
155
+#define NBD_FLAG_SEND_CACHE        (1 << NBD_FLAG_SEND_CACHE_BIT)
142 156
 
143 157
 /* New-style handshake (global) flags, sent from server to client, and
144 158
    control what will happen during handshake phase. */

+ 17
- 29
qemu-nbd.c View File

@@ -279,37 +279,25 @@ static int qemu_nbd_client_list(SocketAddress *saddr, QCryptoTLSCreds *tls,
279 279
             printf("  description: %s\n", list[i].description);
280 280
         }
281 281
         if (list[i].flags & NBD_FLAG_HAS_FLAGS) {
282
+            static const char *const flag_names[] = {
283
+                [NBD_FLAG_READ_ONLY_BIT]            = "readonly",
284
+                [NBD_FLAG_SEND_FLUSH_BIT]           = "flush",
285
+                [NBD_FLAG_SEND_FUA_BIT]             = "fua",
286
+                [NBD_FLAG_ROTATIONAL_BIT]           = "rotational",
287
+                [NBD_FLAG_SEND_TRIM_BIT]            = "trim",
288
+                [NBD_FLAG_SEND_WRITE_ZEROES_BIT]    = "zeroes",
289
+                [NBD_FLAG_SEND_DF_BIT]              = "df",
290
+                [NBD_FLAG_CAN_MULTI_CONN_BIT]       = "multi",
291
+                [NBD_FLAG_SEND_RESIZE_BIT]          = "resize",
292
+                [NBD_FLAG_SEND_CACHE_BIT]           = "cache",
293
+            };
294
+
282 295
             printf("  size:  %" PRIu64 "\n", list[i].size);
283 296
             printf("  flags: 0x%x (", list[i].flags);
284
-            if (list[i].flags & NBD_FLAG_READ_ONLY) {
285
-                printf(" readonly");
286
-            }
287
-            if (list[i].flags & NBD_FLAG_SEND_FLUSH) {
288
-                printf(" flush");
289
-            }
290
-            if (list[i].flags & NBD_FLAG_SEND_FUA) {
291
-                printf(" fua");
292
-            }
293
-            if (list[i].flags & NBD_FLAG_ROTATIONAL) {
294
-                printf(" rotational");
295
-            }
296
-            if (list[i].flags & NBD_FLAG_SEND_TRIM) {
297
-                printf(" trim");
298
-            }
299
-            if (list[i].flags & NBD_FLAG_SEND_WRITE_ZEROES) {
300
-                printf(" zeroes");
301
-            }
302
-            if (list[i].flags & NBD_FLAG_SEND_DF) {
303
-                printf(" df");
304
-            }
305
-            if (list[i].flags & NBD_FLAG_CAN_MULTI_CONN) {
306
-                printf(" multi");
307
-            }
308
-            if (list[i].flags & NBD_FLAG_SEND_RESIZE) {
309
-                printf(" resize");
310
-            }
311
-            if (list[i].flags & NBD_FLAG_SEND_CACHE) {
312
-                printf(" cache");
297
+            for (size_t bit = 0; bit < ARRAY_SIZE(flag_names); bit++) {
298
+                if (flag_names[bit] && (list[i].flags & (1 << bit))) {
299
+                    printf(" %s", flag_names[bit]);
300
+                }
313 301
             }
314 302
             printf(" )\n");
315 303
         }

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