Patch "irqchip/gic-v3-its: Recompute the number of pages on page size change" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

irqchip/gic-v3-its: Recompute the number of pages on page size change

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
irqchip-gic-v3-its-recompute-the-number-of-pages-on-page-size-change.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Marc Zyngier <[email protected]>
Date: Tue, 26 Jan 2016 14:24:15 +0000
Subject: irqchip/gic-v3-its: Recompute the number of pages on page size change

From: Marc Zyngier <[email protected]>

commit 18aa60ce2751c95d3412ed06a58b8b6cfb6f88f2 upstream.

When the programming of a GITS_BASERn register fails because of an unsupported ITS page size, we retry it with a smaller page size. Unfortunately, we don't recompute the number of allocated ITS pages, indicating the wrong value computed in the original allocation.

A convenient fix is to free the pages we allocated, update the page size, and restart the allocation. This will ensure that we always allocate the right amount in the case of a device table, specially if we have to reduce the allocation order to stay within the boundaries of the ITS maximum allocation.

---
 drivers/irqchip/irq-gic-v3-its.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

@@ -884,6 +884,7 @@ static int its_alloc_tables(const char *
 		}
 
 		alloc_size = (1 << order) * PAGE_SIZE;
+retry_alloc_baser:
 		alloc_pages = (alloc_size / psz);
 		if (alloc_pages > GITS_BASER_PAGES_MAX) {
 			alloc_pages = GITS_BASER_PAGES_MAX;

@@ -947,13 +948,16 @@ retry_baser:
 			 * size and retry. If we reach 4K, then
 			 * something is horribly wrong...
 			 */
+			free_pages((unsigned long)base, order);
+			its->tables[i] = NULL;
+
 			switch (psz) {
 			case SZ_16K:
 				psz = SZ_4K;
-				goto retry_baser;
+				goto retry_alloc_baser;
 			case SZ_64K:
 				psz = SZ_16K;
-				goto retry_baser;
+				goto retry_alloc_baser;
 			}
 		}
 

Patches currently in stable-queue which might be from marc.zyngier at arm.com are

queue-4.4/irqchip-gicv3-its-avoid-cache-flush-beyond-its_basern-memory-size.patch queue-4.4/irqchip-gic-make-interrupt-id-1020-invalid.patch queue-4.4/irqchip-bcm7038-l1-hide-cpu-offline-callback-when-building-for-smp.patch queue-4.4/irqchip-gic-v3-add-missing-barrier-to-32bit-version-of-gic_read_iar.patch queue-4.4/irqchip-gicv3-its-fix-memory-leak-in-its_free_tables.patch queue-4.4/irqchip-gic-v3-its-recompute-the-number-of-pages-on-page-size-change.patch queue-4.4/genirq-delay-incrementing-interrupt-count-if-it-s-disabled-pending.patch