Subject: [merged] ipcshm-document-new-limits-in-the-uapi-header.patch removed from -mm tree
To: davidlohr@xxxxxx,manfred@xxxxxxxxxxxxxxxx,mtk.manpages@xxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 09 Jun 2014 12:37:32 -0700
The patch titled
Subject: ipc,shm: document new limits in the uapi header
has been removed from the -mm tree. Its filename was
ipcshm-document-new-limits-in-the-uapi-header.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Davidlohr Bueso <davidlohr@xxxxxx>
Subject: ipc,shm: document new limits in the uapi header
This is useful in the future and allows users to better understand the
reasoning behind the changes.
Also use UL as we're dealing with it anyways.
Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/uapi/linux/shm.h | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff -puN include/uapi/linux/shm.h~ipcshm-document-new-limits-in-the-uapi-header include/uapi/linux/shm.h
--- a/include/uapi/linux/shm.h~ipcshm-document-new-limits-in-the-uapi-header
+++ a/include/uapi/linux/shm.h
@@ -8,17 +8,20 @@
#endif
/*
- * SHMMAX, SHMMNI and SHMALL are upper limits are defaults which can
- * be modified by sysctl.
+ * SHMMNI, SHMMAX and SHMALL are default upper limits which can be
+ * modified by sysctl. The SHMMAX and SHMALL values have been chosen to
+ * be as large possible without facilitating scenarios where userspace
+ * causes overflows when adjusting the limits via operations of the form
+ * "retrieve current limit; add X; update limit". It is therefore not
+ * advised to make SHMMAX and SHMALL any larger. These limits are
+ * suitable for both 32 and 64-bit systems.
*/
-
#define SHMMIN 1 /* min shared seg size (bytes) */
#define SHMMNI 4096 /* max num of segs system wide */
-#define SHMMAX (ULONG_MAX - (1L<<24)) /* max shared seg size (bytes) */
-#define SHMALL (ULONG_MAX - (1L<<24)) /* max shm system wide (pages) */
+#define SHMMAX (ULONG_MAX - (1UL << 24)) /* max shared seg size (bytes) */
+#define SHMALL (ULONG_MAX - (1UL << 24)) /* max shm system wide (pages) */
#define SHMSEG SHMMNI /* max shared segs per process */
-
/* Obsolete, used only for backwards compatibility and libc5 compiles */
struct shmid_ds {
struct ipc_perm shm_perm; /* operation perms */
_
Patches currently in -mm which might be from davidlohr@xxxxxx are
origin.patch
m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch
linux-next.patch
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