floppy: add defines for sizes of cmd & reply buffers of floppy_raw_cmd

Use FD_RAW_CMD_SIZE, FD_RAW_REPLY_SIZE defines instead of magic numbers
for cmd & reply buffers of struct floppy_raw_cmd. Remove local to
floppy.c MAX_REPLIES define, as it is now FD_RAW_REPLY_SIZE.
FD_RAW_CMD_FULLSIZE added as we allow command to also fill reply_count
and reply fields.

Link: https://lore.kernel.org/r/20200501134416.72248-4-efremov@linux.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Denis Efremov <efremov@linux.com>

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index b82b3d38b834edd25f2df2ebe9641e82a67d4598..9e098d53b046b71765ae7dcf4725c8189c5694a9 100644 (file)
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -337,8 +337,7 @@ static bool initialized;
 /*
  * globals used by 'result()'
  */
-#define MAX_REPLIES 16
-static unsigned char reply_buffer[MAX_REPLIES];
+static unsigned char reply_buffer[FD_RAW_REPLY_SIZE];
 static int inr;                /* size of reply buffer, when called from interrupt */
 #define ST0            0
 #define ST1            1
@@ -1162,7 +1161,7 @@ static int result(int fdc)
        int i;
        int status = 0;
 
-       for (i = 0; i < MAX_REPLIES; i++) {
+       for (i = 0; i < FD_RAW_REPLY_SIZE; i++) {
                status = wait_til_ready(fdc);
                if (status < 0)
                        break;
@@ -3079,7 +3078,7 @@ static void raw_cmd_done(int flag)
                raw_cmd->flags |= FD_RAW_HARDFAILURE;
        } else {
                raw_cmd->reply_count = inr;
-               if (raw_cmd->reply_count > MAX_REPLIES)
+               if (raw_cmd->reply_count > FD_RAW_REPLY_SIZE)
                        raw_cmd->reply_count = 0;
                for (i = 0; i < raw_cmd->reply_count; i++)
                        raw_cmd->reply[i] = reply_buffer[i];
@@ -3190,18 +3189,10 @@ loop:
        if (ret)
                return -EFAULT;
        param += sizeof(struct floppy_raw_cmd);
-       if (ptr->cmd_count > 33)
-                       /* the command may now also take up the space
-                        * initially intended for the reply & the
-                        * reply count. Needed for long 82078 commands
-                        * such as RESTORE, which takes ... 17 command
-                        * bytes. Murphy's law #137: When you reserve
-                        * 16 bytes for a structure, you'll one day
-                        * discover that you really need 17...
-                        */
+       if (ptr->cmd_count > FD_RAW_CMD_FULLSIZE)
                return -EINVAL;
 
-       for (i = 0; i < 16; i++)
+       for (i = 0; i < FD_RAW_REPLY_SIZE; i++)
                ptr->reply[i] = 0;
        ptr->resultcode = 0;
 

diff --git a/include/uapi/linux/fd.h b/include/uapi/linux/fd.h
index 3f6b7be4c096d8a00c5e6ef5c39ceac8f2d77d5f..2e9c2c1c18e6fb029dcc706bfe526f34cf65b733 100644 (file)
--- a/include/uapi/linux/fd.h
+++ b/include/uapi/linux/fd.h
@@ -360,10 +360,20 @@ struct floppy_raw_cmd {
        int buffer_length; /* length of allocated buffer */
 
        unsigned char rate;
+
+#define FD_RAW_CMD_SIZE 16
+#define FD_RAW_REPLY_SIZE 16
+#define FD_RAW_CMD_FULLSIZE (FD_RAW_CMD_SIZE + 1 + FD_RAW_REPLY_SIZE)
+
+       /* The command may take up the space initially intended for the reply
+        * and the reply count. Needed for long 82078 commands such as RESTORE,
+        * which takes 17 command bytes.
+        */
+
        unsigned char cmd_count;
-       unsigned char cmd[16];
+       unsigned char cmd[FD_RAW_CMD_SIZE];
        unsigned char reply_count;
-       unsigned char reply[16];
+       unsigned char reply[FD_RAW_REPLY_SIZE];
        int track;
        int resultcode;