The following commit has been merged into the x86/iopl branch of tip:
Commit-ID: 32f3bf67ee78332f2caec0984cb9d412cd0a3c23
Gitweb: https://git.kernel.org/tip/32f3bf67ee78332f2caec0984cb9d412cd0a3c23
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 12 Nov 2019 19:56:19 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Sat, 16 Nov 2019 11:24:01 +01:00
x86/ioperm: Avoid bitmap allocation if no permissions are set
If ioperm() is invoked the first time and the @turn_on argument is 0, then
there is no point to allocate a bitmap just to clear permissions which are
not set.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/ioport.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index ca6aa1e..80fa36b 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -36,6 +36,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
*/
bitmap = t->io_bitmap_ptr;
if (!bitmap) {
+ /* No point to allocate a bitmap just to clear permissions */
+ if (!turn_on)
+ return 0;
bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
if (!bitmap)
return -ENOMEM;
|