blockdev: support --get/setra

function                                             old     new   delta
blockdev_main                                        251     263     +12
bdcmd_names                                           82      94     +12
packed_usage                                       33534   33542      +8
bdcmd_ioctl                                           44      52      +8
bdcmd_flags                                           11      13      +2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/0 up/down: 42/0)               Total: 42 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 23 insertions, 5 deletions

diff --git a/util-linux/blockdev.c b/util-linux/blockdev.c
index 20a031377..3b550220a 100644
--- a/util-linux/blockdev.c
+++ b/util-linux/blockdev.c
@@ -25,8 +25,11 @@
 //usage:     "\n        --getbsz        Get block size"
 //usage:     "\n        --setbsz BYTES  Set block size"
 //usage:     "\n        --getsz         Get device size in 512-byte sectors"
-/*//usage:     "\n      --getsize       Get device size in sectors (deprecated)"*/
+///////:     "\n        --getsize       Get device size in sectors (deprecated)"
+///////^^^^^ supported, but not shown in help ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 //usage:     "\n        --getsize64     Get device size in bytes"
+//usage:     "\n        --getra         Get readahead in 512-byte sectors"
+//usage:     "\n        --setra SECTORS Set readahead"
 //usage:     "\n        --flushbufs     Flush buffers"
 //usage:     "\n        --rereadpt      Reread partition table"
 // util-linux 2.31 also has:
@@ -57,6 +60,9 @@ static const char bdcmd_names[] ALIGN1 =
         "getsz"     "\0"
         "getsize"   "\0"
         "getsize64" "\0"
+        "getra"     "\0"
+        "setra"     "\0"
+#define CMD_SETRA 10
         "flushbufs" "\0"
         "rereadpt"  "\0"
 ;
@@ -70,6 +76,8 @@ static const uint32_t bdcmd_ioctl[] ALIGN4 = {
         BLKGETSIZE64,   //getsz
         BLKGETSIZE,     //getsize
         BLKGETSIZE64,   //getsize64
+        BLKRAGET,       //getra
+        BLKRASET,       //setra
         BLKFLSBUF,      //flushbufs
         BLKRRPART,      //rereadpt
 };
@@ -95,6 +103,8 @@ static const uint8_t bdcmd_flags[] ALIGN1 = {
         ARG_U64 + FL_SCALE512,             //getsz
         ARG_ULONG,                         //getsize
         ARG_U64,                           //getsize64
+        ARG_ULONG,                         //getra
+        ARG_ULONG + FL_NORESULT,           //setra
         ARG_NONE + FL_NORESULT,            //flushbufs
         ARG_NONE + FL_NORESULT,            //rereadpt
 };
@@ -130,8 +140,9 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
         /* setrw translates to BLKROSET(0), most other ioctls don't care... */
         /* ...setro will do BLKROSET(1) */
         u64 = (bdcmd == CMD_SETRO);
-        if (bdcmd == CMD_SETBSZ) {
+        if (bdcmd == CMD_SETBSZ || bdcmd == CMD_SETRA) {
                 /* ...setbsz is BLKBSZSET(bytes) */
+                /* ...setra is BLKRASET(512 bytes) */
                 u64 = xatoi_positive(*++argv);
         }
 
@@ -145,8 +156,11 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
 #if BB_BIG_ENDIAN
         /* Store data properly wrt data size.
          * (1) It's no-op for little-endian.
-         * (2) it's no-op for 0 and -1. Only --setro uses arg != 0 and != -1,
-         * and it is ARG_INT. --setbsz USER_VAL is also ARG_INT.
+         * (2) it's no-op for 0 and -1.
+         * --setro uses arg != 0 and != -1, and it is ARG_INT
+         * --setbsz USER_VAL is also ARG_INT
+         * --setra USER_VAL is ARG_ULONG, but it is passed by value,
+         * not reference (see below in ioctl call).
          * Thus, we don't need to handle ARG_ULONG.
          */
         switch (flags & ARG_MASK) {
@@ -161,7 +175,11 @@ int blockdev_main(int argc UNUSED_PARAM, char **argv)
         }
 #endif
 
-        if (ioctl(fd, bdcmd_ioctl[bdcmd], &ioctl_val_on_stack.u64) == -1)
+        if (ioctl(fd, bdcmd_ioctl[bdcmd],
+                        bdcmd == CMD_SETRA
+                                ? (void*)(uintptr_t)u64 /* BLKRASET passes _value_, not pointer to it */
+                                : &ioctl_val_on_stack.u64
+                ) == -1)
                 bb_simple_perror_msg_and_die(*argv);
 
         /* Fetch it into register(s) */