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x86/ioperm: Avoid bitmap allocation if no permissions are set

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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@linutronix.de>
This commit is contained in:
Thomas Gleixner 2019-11-12 19:56:19 +01:00
parent ae31cea86a
commit 32f3bf67ee
1 changed files with 3 additions and 0 deletions
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3
arch/x86/kernel/ioport.c
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@ -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;