linux-user/syscall.c: drop 64 suffix from flock64 &Co

Since we are always building with LFS enabled, in particular
with -D_FILE_OFFSET_BITS=64, we should always have struct flock
mapped to the 64bit variant (with off64_t), and F_GETLK mapped
to F_GETLK64 etc, automatically.

So there should be no need to explicitly use the "64" suffix
for these things anymore.

Also fix a misleading comment near safe_fcntl telling us to
always use flock64 (since v2.6.0-1311-g435da5e7092a "linux-user:
Use safe_syscall wrapper for fcntl").

Reference: https://gitlab.com/qemu-project/qemu/-/issues/2215
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index b693aef..48c459e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -759,10 +759,8 @@
  * the libc function.
  */
 #define safe_ioctl(...) safe_syscall(__NR_ioctl, __VA_ARGS__)
-/* Similarly for fcntl. Note that callers must always:
- *  pass the F_GETLK64 etc constants rather than the unsuffixed F_GETLK
- *  use the flock64 struct rather than unsuffixed flock
- * This will then work and use a 64-bit offset for both 32-bit and 64-bit hosts.
+/* Similarly for fcntl. Since we always build with LFS enabled,
+ * we should be using the 64-bit structures automatically.
  */
 #ifdef __NR_fcntl64
 #define safe_fcntl(...) safe_syscall(__NR_fcntl64, __VA_ARGS__)
@@ -6722,13 +6720,13 @@
         ret = cmd;
         break;
     case TARGET_F_GETLK:
-        ret = F_GETLK64;
+        ret = F_GETLK;
         break;
     case TARGET_F_SETLK:
-        ret = F_SETLK64;
+        ret = F_SETLK;
         break;
     case TARGET_F_SETLKW:
-        ret = F_SETLKW64;
+        ret = F_SETLKW;
         break;
     case TARGET_F_GETOWN:
         ret = F_GETOWN;
@@ -6744,13 +6742,13 @@
         break;
 #if TARGET_ABI_BITS == 32
     case TARGET_F_GETLK64:
-        ret = F_GETLK64;
+        ret = F_GETLK;
         break;
     case TARGET_F_SETLK64:
-        ret = F_SETLK64;
+        ret = F_SETLK;
         break;
     case TARGET_F_SETLKW64:
-        ret = F_SETLKW64;
+        ret = F_SETLKW;
         break;
 #endif
     case TARGET_F_SETLEASE:
@@ -6804,8 +6802,8 @@
      * them to 5, 6 and 7 before making the syscall(). Since we make the
      * syscall directly, adjust to what is supported by the kernel.
      */
-    if (ret >= F_GETLK64 && ret <= F_SETLKW64) {
-        ret -= F_GETLK64 - 5;
+    if (ret >= F_GETLK && ret <= F_SETLKW) {
+        ret -= F_GETLK - 5;
     }
 #endif
 
@@ -6838,7 +6836,7 @@
     return type;
 }
 
-static inline abi_long copy_from_user_flock(struct flock64 *fl,
+static inline abi_long copy_from_user_flock(struct flock *fl,
                                             abi_ulong target_flock_addr)
 {
     struct target_flock *target_fl;
@@ -6863,7 +6861,7 @@
 }
 
 static inline abi_long copy_to_user_flock(abi_ulong target_flock_addr,
-                                          const struct flock64 *fl)
+                                          const struct flock *fl)
 {
     struct target_flock *target_fl;
     short l_type;
@@ -6882,8 +6880,8 @@
     return 0;
 }
 
-typedef abi_long from_flock64_fn(struct flock64 *fl, abi_ulong target_addr);
-typedef abi_long to_flock64_fn(abi_ulong target_addr, const struct flock64 *fl);
+typedef abi_long from_flock64_fn(struct flock *fl, abi_ulong target_addr);
+typedef abi_long to_flock64_fn(abi_ulong target_addr, const struct flock *fl);
 
 #if defined(TARGET_ARM) && TARGET_ABI_BITS == 32
 struct target_oabi_flock64 {
@@ -6894,7 +6892,7 @@
     abi_int   l_pid;
 } QEMU_PACKED;
 
-static inline abi_long copy_from_user_oabi_flock64(struct flock64 *fl,
+static inline abi_long copy_from_user_oabi_flock64(struct flock *fl,
                                                    abi_ulong target_flock_addr)
 {
     struct target_oabi_flock64 *target_fl;
@@ -6919,7 +6917,7 @@
 }
 
 static inline abi_long copy_to_user_oabi_flock64(abi_ulong target_flock_addr,
-                                                 const struct flock64 *fl)
+                                                 const struct flock *fl)
 {
     struct target_oabi_flock64 *target_fl;
     short l_type;
@@ -6939,7 +6937,7 @@
 }
 #endif
 
-static inline abi_long copy_from_user_flock64(struct flock64 *fl,
+static inline abi_long copy_from_user_flock64(struct flock *fl,
                                               abi_ulong target_flock_addr)
 {
     struct target_flock64 *target_fl;
@@ -6964,7 +6962,7 @@
 }
 
 static inline abi_long copy_to_user_flock64(abi_ulong target_flock_addr,
-                                            const struct flock64 *fl)
+                                            const struct flock *fl)
 {
     struct target_flock64 *target_fl;
     short l_type;
@@ -6985,7 +6983,7 @@
 
 static abi_long do_fcntl(int fd, int cmd, abi_ulong arg)
 {
-    struct flock64 fl64;
+    struct flock fl;
 #ifdef F_GETOWN_EX
     struct f_owner_ex fox;
     struct target_f_owner_ex *target_fox;
@@ -6998,45 +6996,45 @@
 
     switch(cmd) {
     case TARGET_F_GETLK:
-        ret = copy_from_user_flock(&fl64, arg);
+        ret = copy_from_user_flock(&fl, arg);
         if (ret) {
             return ret;
         }
-        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl));
         if (ret == 0) {
-            ret = copy_to_user_flock(arg, &fl64);
+            ret = copy_to_user_flock(arg, &fl);
         }
         break;
 
     case TARGET_F_SETLK:
     case TARGET_F_SETLKW:
-        ret = copy_from_user_flock(&fl64, arg);
+        ret = copy_from_user_flock(&fl, arg);
         if (ret) {
             return ret;
         }
-        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl));
         break;
 
     case TARGET_F_GETLK64:
     case TARGET_F_OFD_GETLK:
-        ret = copy_from_user_flock64(&fl64, arg);
+        ret = copy_from_user_flock64(&fl, arg);
         if (ret) {
             return ret;
         }
-        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl));
         if (ret == 0) {
-            ret = copy_to_user_flock64(arg, &fl64);
+            ret = copy_to_user_flock64(arg, &fl);
         }
         break;
     case TARGET_F_SETLK64:
     case TARGET_F_SETLKW64:
     case TARGET_F_OFD_SETLK:
     case TARGET_F_OFD_SETLKW:
-        ret = copy_from_user_flock64(&fl64, arg);
+        ret = copy_from_user_flock64(&fl, arg);
         if (ret) {
             return ret;
         }
-        ret = get_errno(safe_fcntl(fd, host_cmd, &fl64));
+        ret = get_errno(safe_fcntl(fd, host_cmd, &fl));
         break;
 
     case TARGET_F_GETFL:
@@ -12403,7 +12401,7 @@
     case TARGET_NR_fcntl64:
     {
         int cmd;
-        struct flock64 fl;
+        struct flock fl;
         from_flock64_fn *copyfrom = copy_from_user_flock64;
         to_flock64_fn *copyto = copy_to_user_flock64;