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SubjectRe: [PATCH] [SYSVIPC] Change shm_tot from int to size_t
On Fri, Jun 25, 2004 at 10:41:13AM -0500, Makhlis, Lev wrote:

> I see that shm_tot (the total number of pages in shm segments) in
> ipc/shm.c is defined as int, even though its max value (shmall) is size_t.
>
> Admittedly, it only matters for systems with >8TB memory, but shouldn't
> shm_tot also be size_t? The attached patch makes it so.

> -static int shm_tot; /* total number of shared memory pages */
> +static size_t shm_tot; /* total number of shared memory pages */

First, please avoid attachments.

Secondly, this makes shm_tot unsigned. Have you checked all places
where it occurs in an inequality to see whether the semantics did
change? (It looks OK.)

Thirdly, shm_tot is transmitted to userspace (via the SHM_INFO ioctl)
as an unsigned long. If it is necessary to make it larger, then we
must do something with this ioctl. For example, return -1 there
in case the actual value does not fit in an unsigned long.


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