The patch titled
optimize compat_core_sys_select() by a using stack space for small fd sets
has been removed from the -mm tree. Its filename was
optimize-compat_core_sys_select-by-a-using-stack-space-for-small-fd-sets.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: optimize compat_core_sys_select() by a using stack space for small fd sets
From: Badari Pulavarty <pbadari@xxxxxxxxxx>
Optimize select by a using stack space for small fd sets.
core_sys_select() already has this optimization. This is for compat
version.
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/compat.c | 17 +++++++++++------
1 files changed, 11 insertions(+), 6 deletions(-)
diff -puN fs/compat.c~optimize-compat_core_sys_select-by-a-using-stack-space-for-small-fd-sets fs/compat.c
--- a/fs/compat.c~optimize-compat_core_sys_select-by-a-using-stack-space-for-small-fd-sets
+++ a/fs/compat.c
@@ -1544,9 +1544,10 @@ int compat_core_sys_select(int n, compat
compat_ulong_t __user *outp, compat_ulong_t __user *exp, s64 *timeout)
{
fd_set_bits fds;
- char *bits;
+ void *bits;
int size, max_fds, ret = -EINVAL;
struct fdtable *fdt;
+ long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
if (n < 0)
goto out_nofds;
@@ -1564,11 +1565,14 @@ int compat_core_sys_select(int n, compat
* since we used fdset we need to allocate memory in units of
* long-words.
*/
- ret = -ENOMEM;
size = FDS_BYTES(n);
- bits = kmalloc(6 * size, GFP_KERNEL);
- if (!bits)
- goto out_nofds;
+ bits = stack_fds;
+ if (size > sizeof(stack_fds) / 6) {
+ bits = kmalloc(6 * size, GFP_KERNEL);
+ ret = -ENOMEM;
+ if (!bits)
+ goto out_nofds;
+ }
fds.in = (unsigned long *) bits;
fds.out = (unsigned long *) (bits + size);
fds.ex = (unsigned long *) (bits + 2*size);
@@ -1600,7 +1604,8 @@ int compat_core_sys_select(int n, compat
compat_set_fd_set(n, exp, fds.res_ex))
ret = -EFAULT;
out:
- kfree(bits);
+ if (bits != stack_fds)
+ kfree(bits);
out_nofds:
return ret;
}
_
Patches currently in -mm which might be from pbadari@xxxxxxxxxx are
-
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