Re: [UPDATED PATCH] fix memory corruption from misinterpreted bad_inode_ops return values

[Phillip Lougher <phillip@lougher.demon.co.uk>]

Eric Sandeen wrote:
>but Al felt that it was probably better to create an EIO-returner for each 
>actual op signature.  Since so few ops share a signature, I just went ahead 
>& created an EIO function for each individual file & inode op that returns
>a value.

Hmm, the problem with this is it bloats bad_inode.o with lots of empty
functions that return -EIO.  Even though we're not interested in the
parameters, GCC doesn't know this, and doesn't fold the functions into only
the couple of definitions that return different types.

Text size of original bad_inode.o:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         0000006c  00000000  00000000  00000034  2**2

== 108 bytes

Size with patch applied:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         0000016b  00000000  00000000  00000034  2**2 patch
applied:

== 363 bytes, or over three times larger!

>I originally had coded up the fix by creating a return_EIO_<TYPE> macro 
>for each return type,

This adds two extra functions (return for ssize_t and long), which gives an
increase in size of only 12 bytes:

Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000078  00000000  00000000  00000034  2**2

== 120 bytes.

Isn't this better?

Thanks

Phillip

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