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[Qemu-devel] [PATCH] Swap only altered elements of the grouplist
From: |
Kirill A. Shutemov |
Subject: |
[Qemu-devel] [PATCH] Swap only altered elements of the grouplist |
Date: |
Sat, 23 Aug 2008 03:19:21 +0300 |
getgroups returns the number of supplementary group IDs is returned.
So it's unnessary to swap the entire array. It can dramatically speed up
the syscall: on recent Linux kernel NGROUPS_MAX=65536.
Signed-off-by: Kirill A. Shutemov <address@hidden>
---
linux-user/syscall.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 1f0ab34..9d76ade 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5248,7 +5248,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
target_grouplist = lock_user(VERIFY_WRITE, arg2, gidsetsize *
2, 0);
if (!target_grouplist)
goto efault;
- for(i = 0;i < gidsetsize; i++)
+ for(i = 0;i < ret; i++)
target_grouplist[i] = tswap16(grouplist[i]);
unlock_user(target_grouplist, arg2, gidsetsize * 2);
}
@@ -5402,7 +5402,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
ret = -TARGET_EFAULT;
goto fail;
}
- for(i = 0;i < gidsetsize; i++)
+ for(i = 0;i < ret; i++)
target_grouplist[i] = tswap32(grouplist[i]);
unlock_user(target_grouplist, arg2, gidsetsize * 4);
}
--
1.5.6.5.GIT